https://www.trccompsci.online/mediawiki/api.php?action=feedcontributions&user=000032680&feedformat=atomTRCCompSci - AQA Computer Science - User contributions [en-gb]2024-03-29T14:50:17ZUser contributionsMediaWiki 1.31.6https://www.trccompsci.online/mediawiki/index.php?title=Thin_Client_/_Thick_Client&diff=7688Thin Client / Thick Client2019-11-18T14:13:20Z<p>000032680: /* Question 4 */</p>
<hr />
<div>==Overview==<br />
<br />
<youtube>https://www.youtube.com/watch?v=03n1riV0UO8&list=PLCiOXwirraUDUYF_qDYcZV8Hce8dsE_Ho</youtube><br />
<br />
https://www.youtube.com/watch?v=03n1riV0UO8&list=PLCiOXwirraUDUYF_qDYcZV8Hce8dsE_Ho<br />
<br />
=Thin Clients=<br />
<br />
A thin client is the term used when a dummy pc is used, a network PC without HDD to act as a terminal. This is because the data processing mostly occurs on the server itself. It is also a term used when most of the software of the network pc you are using is on the server itself rather than the pc.<br />
Thin clients require constant server communication to be keep running the way it should.<br />
<br />
==Advantages and Disadvantages==<br />
<br />
* Easy to deploy requiring no extra or specialised software installations<br />
* Need to validate with the server after data capture<br />
* If the server goes down the collection of the data will go down<br />
* Any workstation can be used on the network to do the same thing<br />
* Reduced security threat<br />
<br />
=Thick Clients=<br />
A thick client is the term used when a network pc that does most of its own processing for on the client itself rather than the server like a thin client. It also refers to the fact software is on the PC itself rather than a server. If the applications you are using require multimedia components or are bandwidth intensive a thick client will be much more effective.<br />
<br />
==Advantages and Disadvantages==<br />
<br />
* Thick clients are much more expensive and require more IT work in the future<br />
* Data verified by client immediately<br />
* Only requires some communication with server<br />
* Reduced server demands<br />
* Increased security issues<br />
<br />
=Revision Questions=<br />
===Question 1===<br />
<quiz display=simple><br />
{which of the following apply to thick client network?<br />
|type="[]"}<br />
+most of processing done on device instead of server<br />
|| this is true<br />
+better for multiple devices than peer to peer<br />
|| easier to manage<br />
+less reliant on server than thin client<br />
||thin client almost all processing on server<br />
+well protected from malware<br />
||less reliant on central device so less susceptible and easily backed up and protected<br />
</quiz><br />
<br />
===Question 2===<br />
===Question 3===<br />
===Question 4===<br />
<quiz display=simple><br />
{Thick Client is when all of the processing takes place on the client machine<br />
|type="()"}<br />
+ True<br />
- False<br />
</quiz><br />
<br />
===Question 5===<br />
===Question 6===<br />
===Question 7===<br />
===Question 8===<br />
===Question 9===<br />
===Question 10===<br />
===Question 11===<br />
===Question 12===</div>000032680https://www.trccompsci.online/mediawiki/index.php?title=Client_Server_/_Peer_to_Peer&diff=7687Client Server / Peer to Peer2019-11-18T14:10:35Z<p>000032680: /* Question 4 */</p>
<hr />
<div>==Overview==<br />
===CraigNDave===<br />
<youtube>https://www.youtube.com/watch?v=Z67WhfeBIgg&list=PLCiOXwirraUDvVsza-xO2mMwW9QBIa_FG&index=2</youtube><br />
<br />
https://www.youtube.com/watch?v=Z67WhfeBIgg&list=PLCiOXwirraUDvVsza-xO2mMwW9QBIa_FG&index=2<br />
<br />
===Computer Science Tutor===<br />
<youtube>TdQgP_Gee_A</youtube><br />
<br />
https://www.youtube.com/watch?v=TdQgP_Gee_A&list=PL04uZ7242_M6O_6ITD6ncf7EonVHyBeCm&index=29<br />
<br />
===TRC PowerPoint===<br />
[https://studentthomrothac-my.sharepoint.com/:p:/g/personal/wayne_jones_thomroth_ac_uk/ESBQ7_WhKQ1NvAhbt9bIReUBgy0YYmfvgS5XX5STS9KVEw?e=PffL6S Client Server vs Peer to Peer]<br />
<br />
==Client-Server==<br />
<br />
In a client-server network you have a special class of device called a server, and normal devices called clients. A client device is used during normal day to day tasks, but a server is dedicated just to the task assigned. In client-server networks, client devices make requests for network services to servers, multiple servers may be used for different services. A large network may have a file server, print server, email server, back-up etc. All data is stored on a central server that users can then access, this makes it easier to back up data as it is all in one place. Login servers can be used allowing user accounts and passwords to be the same across all machines, allowing for easy control over access rights.<br />
<br />
===Advantages===<br />
*All files are stored in a central location, and be accessed from any machine.<br />
*Network peripherals are controlled centrally, allowing you to share multiple printers from a single server.<br />
*Backups and network security is controlled centrally, requires the backup of a single location.<br />
*Users can access shared data which is centrally controlled, users can login to any machine.<br />
<br />
===Disadvantages===<br />
*A specialist network operating system is needed.<br />
*The server is expensive to purchase.<br />
*Specialist staff such as a network manger is needed.<br />
*If any part of the network fails a lot of disruption can occur.<br />
<br />
==Peer-Peer==<br />
In a peer to peer network all devices are of equal class. Unlike Client-Server networks, there are no dedicated servers in peer-peer networks. Each workstation in the network acts as both client and server, leaving each individual user to choose what is to be shared between workstations. If passwords are required they are have to be changed individually between multiple devices, making these kind of networks extremely difficult to scale into large organisations. They are also more insecure due to permission management of shares being managed individually.<br />
<br />
===Advantages===<br />
*No special operating system required or any servers (they cant be used as a normal machine).<br />
*Flexible with the ability to add new machines and share resources.<br />
*You can decide what resources will be shared by each machine.<br />
<br />
===Disadvantages===<br />
*Users will have different accounts and passwords on different machines.<br />
*Backups will need to be done on each machine to prevent data loss.<br />
*Sharing a connected resource could slow the machine down for the person using the actual machine.<br />
*You reach a point where it is impossible to manage, user permissions and accounts will need to be set on each machine.<br />
<br />
=Revision Questions=<br />
===Question 1===<br />
<br />
===Question 2===<br />
<br />
===Question 3===<br />
<br />
===Question 4===<br />
<quiz display=simple><br />
{A client server is best used with a small number of computers within a network<br />
|type="()"}<br />
- True<br />
+ False<br />
</quiz><br />
<br />
===Question 5===<br />
<br />
===Question 6===<br />
<br />
===Question 7===<br />
<br />
===Question 8===<br />
<br />
===Question 9===<br />
<br />
===Question 10===<br />
<br />
===Question 11===<br />
<br />
===Question 12===</div>000032680https://www.trccompsci.online/mediawiki/index.php?title=Client_Server_/_Peer_to_Peer&diff=7686Client Server / Peer to Peer2019-11-18T14:09:55Z<p>000032680: </p>
<hr />
<div>==Overview==<br />
===CraigNDave===<br />
<youtube>https://www.youtube.com/watch?v=Z67WhfeBIgg&list=PLCiOXwirraUDvVsza-xO2mMwW9QBIa_FG&index=2</youtube><br />
<br />
https://www.youtube.com/watch?v=Z67WhfeBIgg&list=PLCiOXwirraUDvVsza-xO2mMwW9QBIa_FG&index=2<br />
<br />
===Computer Science Tutor===<br />
<youtube>TdQgP_Gee_A</youtube><br />
<br />
https://www.youtube.com/watch?v=TdQgP_Gee_A&list=PL04uZ7242_M6O_6ITD6ncf7EonVHyBeCm&index=29<br />
<br />
===TRC PowerPoint===<br />
[https://studentthomrothac-my.sharepoint.com/:p:/g/personal/wayne_jones_thomroth_ac_uk/ESBQ7_WhKQ1NvAhbt9bIReUBgy0YYmfvgS5XX5STS9KVEw?e=PffL6S Client Server vs Peer to Peer]<br />
<br />
==Client-Server==<br />
<br />
In a client-server network you have a special class of device called a server, and normal devices called clients. A client device is used during normal day to day tasks, but a server is dedicated just to the task assigned. In client-server networks, client devices make requests for network services to servers, multiple servers may be used for different services. A large network may have a file server, print server, email server, back-up etc. All data is stored on a central server that users can then access, this makes it easier to back up data as it is all in one place. Login servers can be used allowing user accounts and passwords to be the same across all machines, allowing for easy control over access rights.<br />
<br />
===Advantages===<br />
*All files are stored in a central location, and be accessed from any machine.<br />
*Network peripherals are controlled centrally, allowing you to share multiple printers from a single server.<br />
*Backups and network security is controlled centrally, requires the backup of a single location.<br />
*Users can access shared data which is centrally controlled, users can login to any machine.<br />
<br />
===Disadvantages===<br />
*A specialist network operating system is needed.<br />
*The server is expensive to purchase.<br />
*Specialist staff such as a network manger is needed.<br />
*If any part of the network fails a lot of disruption can occur.<br />
<br />
==Peer-Peer==<br />
In a peer to peer network all devices are of equal class. Unlike Client-Server networks, there are no dedicated servers in peer-peer networks. Each workstation in the network acts as both client and server, leaving each individual user to choose what is to be shared between workstations. If passwords are required they are have to be changed individually between multiple devices, making these kind of networks extremely difficult to scale into large organisations. They are also more insecure due to permission management of shares being managed individually.<br />
<br />
===Advantages===<br />
*No special operating system required or any servers (they cant be used as a normal machine).<br />
*Flexible with the ability to add new machines and share resources.<br />
*You can decide what resources will be shared by each machine.<br />
<br />
===Disadvantages===<br />
*Users will have different accounts and passwords on different machines.<br />
*Backups will need to be done on each machine to prevent data loss.<br />
*Sharing a connected resource could slow the machine down for the person using the actual machine.<br />
*You reach a point where it is impossible to manage, user permissions and accounts will need to be set on each machine.<br />
<br />
=Revision Questions=<br />
===Question 1===<br />
<br />
===Question 2===<br />
<br />
===Question 3===<br />
<br />
===Question 4===<br />
<br />
{A client server is best used with a small number of computers within a network<br />
|type="()"}<br />
- True<br />
+ False<br />
</quiz><br />
<br />
===Question 5===<br />
<br />
===Question 6===<br />
<br />
===Question 7===<br />
<br />
===Question 8===<br />
<br />
===Question 9===<br />
<br />
===Question 10===<br />
<br />
===Question 11===<br />
<br />
===Question 12===</div>000032680https://www.trccompsci.online/mediawiki/index.php?title=Client_Server_/_Peer_to_Peer&diff=7685Client Server / Peer to Peer2019-11-18T14:09:26Z<p>000032680: </p>
<hr />
<div>==Overview==<br />
===CraigNDave===<br />
<youtube>https://www.youtube.com/watch?v=Z67WhfeBIgg&list=PLCiOXwirraUDvVsza-xO2mMwW9QBIa_FG&index=2</youtube><br />
<br />
https://www.youtube.com/watch?v=Z67WhfeBIgg&list=PLCiOXwirraUDvVsza-xO2mMwW9QBIa_FG&index=2<br />
<br />
===Computer Science Tutor===<br />
<youtube>TdQgP_Gee_A</youtube><br />
<br />
https://www.youtube.com/watch?v=TdQgP_Gee_A&list=PL04uZ7242_M6O_6ITD6ncf7EonVHyBeCm&index=29<br />
<br />
===TRC PowerPoint===<br />
[https://studentthomrothac-my.sharepoint.com/:p:/g/personal/wayne_jones_thomroth_ac_uk/ESBQ7_WhKQ1NvAhbt9bIReUBgy0YYmfvgS5XX5STS9KVEw?e=PffL6S Client Server vs Peer to Peer]<br />
<br />
==Client-Server==<br />
<br />
In a client-server network you have a special class of device called a server, and normal devices called clients. A client device is used during normal day to day tasks, but a server is dedicated just to the task assigned. In client-server networks, client devices make requests for network services to servers, multiple servers may be used for different services. A large network may have a file server, print server, email server, back-up etc. All data is stored on a central server that users can then access, this makes it easier to back up data as it is all in one place. Login servers can be used allowing user accounts and passwords to be the same across all machines, allowing for easy control over access rights.<br />
<br />
===Advantages===<br />
*All files are stored in a central location, and be accessed from any machine.<br />
*Network peripherals are controlled centrally, allowing you to share multiple printers from a single server.<br />
*Backups and network security is controlled centrally, requires the backup of a single location.<br />
*Users can access shared data which is centrally controlled, users can login to any machine.<br />
<br />
===Disadvantages===<br />
*A specialist network operating system is needed.<br />
*The server is expensive to purchase.<br />
*Specialist staff such as a network manger is needed.<br />
*If any part of the network fails a lot of disruption can occur.<br />
<br />
==Peer-Peer==<br />
In a peer to peer network all devices are of equal class. Unlike Client-Server networks, there are no dedicated servers in peer-peer networks. Each workstation in the network acts as both client and server, leaving each individual user to choose what is to be shared between workstations. If passwords are required they are have to be changed individually between multiple devices, making these kind of networks extremely difficult to scale into large organisations. They are also more insecure due to permission management of shares being managed individually.<br />
<br />
===Advantages===<br />
*No special operating system required or any servers (they cant be used as a normal machine).<br />
*Flexible with the ability to add new machines and share resources.<br />
*You can decide what resources will be shared by each machine.<br />
<br />
===Disadvantages===<br />
*Users will have different accounts and passwords on different machines.<br />
*Backups will need to be done on each machine to prevent data loss.<br />
*Sharing a connected resource could slow the machine down for the person using the actual machine.<br />
*You reach a point where it is impossible to manage, user permissions and accounts will need to be set on each machine.<br />
<br />
=Revision Questions=<br />
===Question 1===<br />
<br />
===Question 2===<br />
<br />
===Question 3===<br />
<br />
===Question 4===<br />
<br />
{A client server is best used with a small number of computers within a network|type="()"}<br />
- True<br />
+ False<br />
</quiz><br />
<br />
===Question 5===<br />
<br />
===Question 6===<br />
<br />
===Question 7===<br />
<br />
===Question 8===<br />
<br />
===Question 9===<br />
<br />
===Question 10===<br />
<br />
===Question 11===<br />
<br />
===Question 12===</div>000032680https://www.trccompsci.online/mediawiki/index.php?title=Client_Server_/_Peer_to_Peer&diff=7684Client Server / Peer to Peer2019-11-18T14:08:25Z<p>000032680: /* Question 4 */</p>
<hr />
<div>==Overview==<br />
===CraigNDave===<br />
<youtube>https://www.youtube.com/watch?v=Z67WhfeBIgg&list=PLCiOXwirraUDvVsza-xO2mMwW9QBIa_FG&index=2</youtube><br />
<br />
https://www.youtube.com/watch?v=Z67WhfeBIgg&list=PLCiOXwirraUDvVsza-xO2mMwW9QBIa_FG&index=2<br />
<br />
===Computer Science Tutor===<br />
<youtube>TdQgP_Gee_A</youtube><br />
<br />
https://www.youtube.com/watch?v=TdQgP_Gee_A&list=PL04uZ7242_M6O_6ITD6ncf7EonVHyBeCm&index=29<br />
<br />
===TRC PowerPoint===<br />
[https://studentthomrothac-my.sharepoint.com/:p:/g/personal/wayne_jones_thomroth_ac_uk/ESBQ7_WhKQ1NvAhbt9bIReUBgy0YYmfvgS5XX5STS9KVEw?e=PffL6S Client Server vs Peer to Peer]<br />
<br />
==Client-Server==<br />
<br />
In a client-server network you have a special class of device called a server, and normal devices called clients. A client device is used during normal day to day tasks, but a server is dedicated just to the task assigned. In client-server networks, client devices make requests for network services to servers, multiple servers may be used for different services. A large network may have a file server, print server, email server, back-up etc. All data is stored on a central server that users can then access, this makes it easier to back up data as it is all in one place. Login servers can be used allowing user accounts and passwords to be the same across all machines, allowing for easy control over access rights.<br />
<br />
===Advantages===<br />
*All files are stored in a central location, and be accessed from any machine.<br />
*Network peripherals are controlled centrally, allowing you to share multiple printers from a single server.<br />
*Backups and network security is controlled centrally, requires the backup of a single location.<br />
*Users can access shared data which is centrally controlled, users can login to any machine.<br />
<br />
===Disadvantages===<br />
*A specialist network operating system is needed.<br />
*The server is expensive to purchase.<br />
*Specialist staff such as a network manger is needed.<br />
*If any part of the network fails a lot of disruption can occur.<br />
<br />
==Peer-Peer==<br />
In a peer to peer network all devices are of equal class. Unlike Client-Server networks, there are no dedicated servers in peer-peer networks. Each workstation in the network acts as both client and server, leaving each individual user to choose what is to be shared between workstations. If passwords are required they are have to be changed individually between multiple devices, making these kind of networks extremely difficult to scale into large organisations. They are also more insecure due to permission management of shares being managed individually.<br />
<br />
===Advantages===<br />
*No special operating system required or any servers (they cant be used as a normal machine).<br />
*Flexible with the ability to add new machines and share resources.<br />
*You can decide what resources will be shared by each machine.<br />
<br />
===Disadvantages===<br />
*Users will have different accounts and passwords on different machines.<br />
*Backups will need to be done on each machine to prevent data loss.<br />
*Sharing a connected resource could slow the machine down for the person using the actual machine.<br />
*You reach a point where it is impossible to manage, user permissions and accounts will need to be set on each machine.<br />
<br />
=Revision Questions=<br />
===Question 1===<br />
<br />
===Question 2===<br />
<quiz display=simple><br />
===Question 3===<br />
<quiz display=simple><br />
===Question 4===<br />
<quiz display=simple><br />
{A client server is best used with a small number of computers within a network|type="()"}<br />
- True<br />
+ False<br />
</quiz><br />
<br />
===Question 5===<br />
<quiz display=simple><br />
===Question 6===<br />
<quiz display=simple><br />
===Question 7===<br />
<quiz display=simple><br />
===Question 8===<br />
<quiz display=simple><br />
===Question 9===<br />
<quiz display=simple><br />
===Question 10===<br />
<quiz display=simple><br />
===Question 11===<br />
<quiz display=simple><br />
===Question 12===<br />
<quiz display=simple></div>000032680https://www.trccompsci.online/mediawiki/index.php?title=Client_Server_/_Peer_to_Peer&diff=7681Client Server / Peer to Peer2019-11-18T14:03:49Z<p>000032680: </p>
<hr />
<div>==Overview==<br />
===CraigNDave===<br />
<youtube>https://www.youtube.com/watch?v=Z67WhfeBIgg&list=PLCiOXwirraUDvVsza-xO2mMwW9QBIa_FG&index=2</youtube><br />
<br />
https://www.youtube.com/watch?v=Z67WhfeBIgg&list=PLCiOXwirraUDvVsza-xO2mMwW9QBIa_FG&index=2<br />
<br />
===Computer Science Tutor===<br />
<youtube>TdQgP_Gee_A</youtube><br />
<br />
https://www.youtube.com/watch?v=TdQgP_Gee_A&list=PL04uZ7242_M6O_6ITD6ncf7EonVHyBeCm&index=29<br />
<br />
===TRC PowerPoint===<br />
[https://studentthomrothac-my.sharepoint.com/:p:/g/personal/wayne_jones_thomroth_ac_uk/ESBQ7_WhKQ1NvAhbt9bIReUBgy0YYmfvgS5XX5STS9KVEw?e=PffL6S Client Server vs Peer to Peer]<br />
<br />
==Client-Server==<br />
<br />
In a client-server network you have a special class of device called a server, and normal devices called clients. A client device is used during normal day to day tasks, but a server is dedicated just to the task assigned. In client-server networks, client devices make requests for network services to servers, multiple servers may be used for different services. A large network may have a file server, print server, email server, back-up etc. All data is stored on a central server that users can then access, this makes it easier to back up data as it is all in one place. Login servers can be used allowing user accounts and passwords to be the same across all machines, allowing for easy control over access rights.<br />
<br />
===Advantages===<br />
*All files are stored in a central location, and be accessed from any machine.<br />
*Network peripherals are controlled centrally, allowing you to share multiple printers from a single server.<br />
*Backups and network security is controlled centrally, requires the backup of a single location.<br />
*Users can access shared data which is centrally controlled, users can login to any machine.<br />
<br />
===Disadvantages===<br />
*A specialist network operating system is needed.<br />
*The server is expensive to purchase.<br />
*Specialist staff such as a network manger is needed.<br />
*If any part of the network fails a lot of disruption can occur.<br />
<br />
==Peer-Peer==<br />
In a peer to peer network all devices are of equal class. Unlike Client-Server networks, there are no dedicated servers in peer-peer networks. Each workstation in the network acts as both client and server, leaving each individual user to choose what is to be shared between workstations. If passwords are required they are have to be changed individually between multiple devices, making these kind of networks extremely difficult to scale into large organisations. They are also more insecure due to permission management of shares being managed individually.<br />
<br />
===Advantages===<br />
*No special operating system required or any servers (they cant be used as a normal machine).<br />
*Flexible with the ability to add new machines and share resources.<br />
*You can decide what resources will be shared by each machine.<br />
<br />
===Disadvantages===<br />
*Users will have different accounts and passwords on different machines.<br />
*Backups will need to be done on each machine to prevent data loss.<br />
*Sharing a connected resource could slow the machine down for the person using the actual machine.<br />
*You reach a point where it is impossible to manage, user permissions and accounts will need to be set on each machine.<br />
<br />
=Revision Questions=<br />
===Question 1===<br />
<quiz display=simple><br />
{which of the following apply to thick client network?<br />
|type="[]"}<br />
+most of processing done on device instead of server<br />
|| this is true<br />
+better for multiple devices than peer to peer<br />
|| easier to manage<br />
+less reliant on server than thin client<br />
||thin client almost all processing on server<br />
+well protected from malware<br />
||less reliant on central device so less susceptible and easily backed up and protected<br />
</quiz><br />
<br />
===Question 2===<br />
<quiz display=simple><br />
===Question 3===<br />
<quiz display=simple><br />
===Question 4===<br />
<quiz display=simple><br />
===Question 5===<br />
<quiz display=simple><br />
===Question 6===<br />
<quiz display=simple><br />
===Question 7===<br />
<quiz display=simple><br />
===Question 8===<br />
<quiz display=simple><br />
===Question 9===<br />
<quiz display=simple><br />
===Question 10===<br />
<quiz display=simple><br />
===Question 11===<br />
<quiz display=simple><br />
===Question 12===<br />
<quiz display=simple></div>000032680https://www.trccompsci.online/mediawiki/index.php?title=Computer_Networks&diff=7663Computer Networks2019-11-15T11:58:58Z<p>000032680: /* Question 12 */</p>
<hr />
<div>=Types of Network=<br />
===Computer Science Tutor===<br />
<youtube>TdQgP_Gee_A</youtube><br />
<br />
https://www.youtube.com/watch?v=TdQgP_Gee_A&list=PL04uZ7242_M6O_6ITD6ncf7EonVHyBeCm&index=29<br />
<br />
==Local Area Network==<br />
Local Area Networks (Also known as "LAN") is a form of networking that allows devices to communitcate to eachother and networks, LAN is connected via an Ethernet cable then connected to a server or a router to connect to a network or another device. LAN is connected by Ethernet Cables, these are made up of coxial cable in different types. This, for a long time, was the only way to connect a computer as they used to have where they would connect to a mainframe and then a computer would be connected by Ethernet cable to the mainframe, making it a Local Area Network.<br />
<br />
==Wide Area Network==<br />
<br />
A Wide Area Network, or WAN, is made up of several computer networks connected together, often over the Internet. In most cases, the networks in WANs all belong to the same company or school. WANs are used to connect LANs and other types of networks together, so that users and computers in one location can communicate with users and computers in other locations. Many WANs are built for one particular organization and are private. Others, built by Internet service providers, provide connections from an organization's LAN to the Internet.<br />
<br />
The following image demonstrates how a wide area network is used in a computer network:<br />
<br />
[[File:17d1c375cab9c86e64c0b5987e1d6fc5109739c3.gif|x500px]]<br />
<br />
=Why do we network devices=<br />
==Benefits of Networking==<br />
* Sharing devices like printers saves money.<br />
* Site licences are likely to be cheaper than buying several standalone licences.<br />
* Files can easily be shared between users.<br />
* Network users can communicate by email.<br />
* Security is good, users cannot see other users' files unlike on stand-alone machines.<br />
* Data is easy to backup as all the data is stored on the file server.<br />
* Single password per user instead of per device.<br />
<br />
==Drawbacks of Networking==<br />
* Purchasing the network cabling and file servers can be expensive.<br />
* Managing a large network is complicated, requires training and a network manager usually needs to be employed.<br />
* If the file server breaks down the files on the file server become inaccessible.<br />
* Viruses can spread to other computers throughout a computer network.<br />
* There is a danger of hacking, particularly with WANs.<br />
* If there's a break in the network is down no work on computers can take place.<br />
<br />
=Revision Questions=<br />
<br />
===Question 1===<br />
<quiz display=simple><br />
{ what does CSMA/CD (carrier sense multiple access with collision detection) do when a collision is detected?<br />
|type ="()"}<br />
-stops sending data from all included devices and produces an error message<br />
||doesn't just just sending<br />
+stops sending data all devices wait a random ammount of time then retry<br />
||correct<br />
-keeps retrying until sent<br />
||incorrect this would not work and will stop the computer<br />
-data is transfered through the air instead<br />
|| this cannot be done with this protocol or possible in these systems<br />
</quiz><br />
<br />
===Question 2===<br />
<quiz display=simple><br />
{ Select all the benefits of networking: <br />
|type = "[]" }<br />
- All devices such as printers are independent to a machine which saves money<br />
|| Incorrect<br />
+ Files can easily be shared between users<br />
|| Correct <br />
+ Data is easy to backup as all the data is stored on the file server<br />
|| Correct <br />
- It's easier to travel<br />
||Leave your fridge open to stop global warming.<br />
+ Site licences are likely to be cheaper than buying several standalone licences<br />
||Correct<br />
</quiz><br />
<br />
===Question 3===<br />
<quiz display=simple><br />
{ Which of the following apply to a LAN? (Multiple Answers) <br />
|type="[]" } <br />
+ It is a form of networking that allows devices to communicate with each other and networks<br />
||This is correct.<br />
- It is connected via fibre optic<br />
||This is incorrect; it is connected via Ethernet<br />
+ It is connected via coaxial cables in the form of Ethernet<br />
||This is correct.<br />
+ It was the only way to connect a computer for a long time.<br />
||This is correct; they used to connect a mainframe to a computer via ethernet<br />
- It is a geographically remote network<br />
||This is incorrect; it is geographically confined.<br />
</quiz><br />
<br />
===Question 4===<br />
<quiz display=simple><br />
{ Define a Peer-peer network:<br />
|type = "()" }<br />
- Devices connected to a server to communicate with each other<br />
|| Incorrect<br />
+ Devices with equal status, with no servers connected <br />
|| Correct <br />
- Devices connected to a WAN <br />
|| Incorrect <br />
</quiz><br />
<br />
===Question 5===<br />
<quiz display=simple><br />
{ Which of the following are typically LAN connection medium?<br />
| type"[]" }<br />
- satellite link<br />
|| satellite link is ''not'' local area<br />
+ Ethernet Cable<br />
|| Correct<br />
- Fibre Optic cable<br />
|| No<br />
+ Wireless connection<br />
|| Correct<br />
</quiz><br />
<br />
===Question 6===<br />
<quiz display=simple><br />
{ What does LAN stand for?<br />
| type="[]" } <br />
- Logical active network.<br />
||Local area network was the correct answer.<br />
- Nothing<br />
||Bruh.<br />
+ Local area network.<br />
||Noice one.<br />
- Live area network.<br />
||Local area network was the correct answer.<br />
</quiz><br />
<br />
===Question 7===<br />
<quiz display=simple><br />
{ What does WAN stand for?<br />
| type="()" } <br />
<br />
- Wired Access Network<br />
|| Incorrect, it stands for Wide Area Network<br />
+ Wide Area Network<br />
|| Correct<br />
- Wireless Anatomy Network<br />
|| Incorrect, it stands for Wide Area Network<br />
- Wayne's Army Network<br />
|| '''NO!''' It stands for Wide Area Network<br />
<br />
</quiz><br />
<br />
===Question 8===<br />
<br />
<quiz display=simple><br />
<br />
{What are the communications media used in a WAN <br />
| type="[]" } <br />
+ Ethernet<br />
||Yes<br />
- USB.<br />
|| no <br />
+ Router.<br />
||yes<br />
+ Hub.<br />
||this is not wrong<br />
+ Switch <br />
|| incorrect <br />
- Coaxial cable<br />
</quiz><br />
<br />
===Question 9===<br />
<quiz display=simple><br />
{Which of these is not a drawback of using LAN? <br />
| type="[]" }<br />
<br />
+ Saves money by sharing devices, like printers<br />
||This is a benefit<br />
- Managing a LAN is complicated<br />
+ Easy to back up data<br />
||This is a benefit<br />
- Viruses can spread to other computers throughout the network<br />
</quiz><br />
<br />
===Question 10===<br />
<quiz display=simple><br />
{ State the advantages of a star topology over the bus topology.<br />
| type="[]" }<br />
+ Less chance of data collisions<br />
|| Correct<br />
+ Easier to detect faults<br />
|| Correct<br />
- Less cable overall is needed<br />
|| Incorrect<br />
- Easier to connect a computer or peripheral compared to a bus topology<br />
|| Incorrect<br />
+ No disruptions to the network when removing and connecting devices<br />
|| Correct<br />
</quiz><br />
<br />
===Question 11===<br />
<quiz display=simple><br />
{ Which of these is an benefit of networking? <br />
| type="()" } <br />
<br />
+ Files can easily be shared between users.<br />
|| Correct answer<br />
- Purchasing the network cabling and file servers can be expensive.<br />
|| The correct answer is "Files can easily be shared between users."<br />
- Managing a large network is complicated, requires training and a network manager usually needs to be employed.<br />
|| The correct answer is "Files can easily be shared between users."<br />
- Viruses can spread to other computers throughout a computer network.<br />
|| The correct answer is "Files can easily be shared between users."<br />
<br />
</quiz><br />
<br />
===Question 12===<br />
<quiz display=simple><br />
{Define the term protocol:<br />
| type="()" }<br />
<br />
- A device that a network can connect to <br />
||Incorrect<br />
+ A set of rules that computers use to communicate with each other<br />
||Correct<br />
- A network topology layout<br />
||Incorrect<br />
- The type of communication method used when computers connect<br />
||Incorrect<br />
<br />
</quiz></div>000032680https://www.trccompsci.online/mediawiki/index.php?title=Computer_Networks&diff=7657Computer Networks2019-11-15T11:53:19Z<p>000032680: /* Question 30 */</p>
<hr />
<div>=Types of Network=<br />
===Computer Science Tutor===<br />
<youtube>TdQgP_Gee_A</youtube><br />
<br />
https://www.youtube.com/watch?v=TdQgP_Gee_A&list=PL04uZ7242_M6O_6ITD6ncf7EonVHyBeCm&index=29<br />
<br />
==Local Area Network==<br />
Local Area Networks (Also known as "LAN") is a form of networking that allows devices to communitcate to eachother and networks, LAN is connected via an Ethernet cable then connected to a server or a router to connect to a network or another device. LAN is connected by Ethernet Cables, these are made up of coxial cable in different types. This, for a long time, was the only way to connect a computer as they used to have where they would connect to a mainframe and then a computer would be connected by Ethernet cable to the mainframe, making it a Local Area Network.<br />
<br />
==Wide Area Network==<br />
<br />
A Wide Area Network, or WAN, is made up of several computer networks connected together, often over the Internet. In most cases, the networks in WANs all belong to the same company or school. WANs are used to connect LANs and other types of networks together, so that users and computers in one location can communicate with users and computers in other locations. Many WANs are built for one particular organization and are private. Others, built by Internet service providers, provide connections from an organization's LAN to the Internet.<br />
<br />
The following image demonstrates how a wide area network is used in a computer network:<br />
<br />
[[File:17d1c375cab9c86e64c0b5987e1d6fc5109739c3.gif|x500px]]<br />
<br />
=Why do we network devices=<br />
==Benefits of Networking==<br />
* Sharing devices like printers saves money.<br />
* Site licences are likely to be cheaper than buying several standalone licences.<br />
* Files can easily be shared between users.<br />
* Network users can communicate by email.<br />
* Security is good, users cannot see other users' files unlike on stand-alone machines.<br />
* Data is easy to backup as all the data is stored on the file server.<br />
* Single password per user instead of per device.<br />
<br />
==Drawbacks of Networking==<br />
* Purchasing the network cabling and file servers can be expensive.<br />
* Managing a large network is complicated, requires training and a network manager usually needs to be employed.<br />
* If the file server breaks down the files on the file server become inaccessible.<br />
* Viruses can spread to other computers throughout a computer network.<br />
* There is a danger of hacking, particularly with WANs.<br />
* If there's a break in the network is down no work on computers can take place.<br />
<br />
=Revision Questions=<br />
<br />
===Question 1===<br />
<quiz display=simple><br />
{ what does CSMA/CD (carrier sense multiple access with collision detection) do when a collision is detected?<br />
|type ="()"}<br />
-stops sending data from all included devices and produces an error message<br />
||doesn't just just sending<br />
+stops sending data all devices wait a random ammount of time then retry<br />
||correct<br />
-keeps retrying until sent<br />
||incorrect this would not work and will stop the computer<br />
-data is transfered through the air instead<br />
|| this cannot be done with this protocol or possible in these systems<br />
</quiz><br />
<br />
===Question 2===<br />
<quiz display=simple><br />
{ Select all the benefits of networking: <br />
|type = "[]" }<br />
- All devices such as printers are independent to a machine which saves money<br />
|| Incorrect<br />
+ Files can easily be shared between users<br />
|| Correct <br />
+ Data is easy to backup as all the data is stored on the file server<br />
|| Correct <br />
- It's easier to travel<br />
||Leave your fridge open to stop global warming.<br />
+ Site licences are likely to be cheaper than buying several standalone licences<br />
||Correct<br />
</quiz><br />
<br />
===Question 3===<br />
<quiz display=simple><br />
{ Which of the following apply to a LAN? (Multiple Answers) <br />
|type="[]" } <br />
+ It is a form of networking that allows devices to communicate with each other and networks<br />
||This is correct.<br />
- It is connected via fibre optic<br />
||This is incorrect; it is connected via Ethernet<br />
+ It is connected via coaxial cables in the form of Ethernet<br />
||This is correct.<br />
+ It was the only way to connect a computer for a long time.<br />
||This is correct; they used to connect a mainframe to a computer via ethernet<br />
- It is a geographically remote network<br />
||This is incorrect; it is geographically confined.<br />
</quiz><br />
<br />
===Question 4===<br />
<quiz display=simple><br />
{ Define a Peer-peer network:<br />
|type = "()" }<br />
- Devices connected to a server to communicate with each other<br />
|| Incorrect<br />
+ Devices with equal status, with no servers connected <br />
|| Correct <br />
- Devices connected to a WAN <br />
|| Incorrect <br />
</quiz><br />
<br />
===Question 5===<br />
<quiz display=simple><br />
{ Which of the following are typically LAN connection medium?<br />
| type"[]" }<br />
- satellite link<br />
|| satellite link is ''not'' local area<br />
+ Ethernet Cable<br />
|| Correct<br />
- Fibre Optic cable<br />
|| No<br />
+ Wireless connection<br />
|| Correct<br />
</quiz><br />
<br />
===Question 6===<br />
<quiz display=simple><br />
{ What does LAN stand for?<br />
| type="[]" } <br />
- Logical active network.<br />
||Local area network was the correct answer.<br />
- Nothing<br />
||Bruh.<br />
+ Local area network.<br />
||Noice one.<br />
- Live area network.<br />
||Local area network was the correct answer.<br />
</quiz><br />
<br />
===Question 7===<br />
<quiz display=simple><br />
{ What does WAN stand for?<br />
| type="()" } <br />
<br />
- Wired Access Network<br />
|| Incorrect, it stands for Wide Area Network<br />
+ Wide Area Network<br />
|| Correct<br />
- Wireless Anatomy Network<br />
|| Incorrect, it stands for Wide Area Network<br />
- Wayne's Army Network<br />
|| '''NO!''' It stands for Wide Area Network<br />
<br />
</quiz><br />
<br />
===Question 8===<br />
<br />
<quiz display=simple><br />
<br />
{What are the communications media used in a WAN <br />
| type="[]" } <br />
+ Ethernet<br />
||Yes<br />
- USB.<br />
|| no <br />
+ Router.<br />
||yes<br />
+ Hub.<br />
||this is not wrong<br />
+ Switch <br />
|| incorrect <br />
- Coaxial cable<br />
</quiz><br />
<br />
===Question 9===<br />
<quiz display=simple><br />
{Which of these is not a drawback of using LAN? <br />
| type="()" }<br />
<br />
+ Saves money by sharing devices, like printers<br />
||Correct, this is a benefit<br />
- Managing a LAN is complicated<br />
||feedback for distractor<br />
- Buying network cabling and file servers can be expensive<br />
||feedback for distractor<br />
- Viruses can spread to other computers throughout the network<br />
||feedback for distractor<br />
</quiz><br />
<br />
===Question 10===<br />
<quiz display=simple><br />
{ State the advantages of a star topology over the bus topology.<br />
| type="[]" }<br />
+ Less chance of data collisions<br />
|| Correct<br />
+ Easier to detect faults<br />
|| Correct<br />
- Less cable overall is needed<br />
|| Incorrect<br />
- Easier to connect a computer or peripheral compared to a bus topology<br />
|| Incorrect<br />
+ No disruptions to the network when removing and connecting devices<br />
|| Correct<br />
</quiz><br />
<br />
===Question 11===<br />
<quiz display=simple><br />
{ Which of these is an benefit of networking? <br />
| type="()" } <br />
<br />
+ Files can easily be shared between users.<br />
|| Correct answer<br />
- Purchasing the network cabling and file servers can be expensive.<br />
|| The correct answer is "Files can easily be shared between users."<br />
- Managing a large network is complicated, requires training and a network manager usually needs to be employed.<br />
|| The correct answer is "Files can easily be shared between users."<br />
- Viruses can spread to other computers throughout a computer network.<br />
|| The correct answer is "Files can easily be shared between users."<br />
<br />
</quiz><br />
<br />
===Question 12===<br />
<quiz display=simple><br />
<br />
</quiz></div>000032680https://www.trccompsci.online/mediawiki/index.php?title=Computer_Networks&diff=7656Computer Networks2019-11-15T11:52:30Z<p>000032680: /* Question 5 */</p>
<hr />
<div>=Types of Network=<br />
===Computer Science Tutor===<br />
<youtube>TdQgP_Gee_A</youtube><br />
<br />
https://www.youtube.com/watch?v=TdQgP_Gee_A&list=PL04uZ7242_M6O_6ITD6ncf7EonVHyBeCm&index=29<br />
<br />
==Local Area Network==<br />
Local Area Networks (Also known as "LAN") is a form of networking that allows devices to communitcate to eachother and networks, LAN is connected via an Ethernet cable then connected to a server or a router to connect to a network or another device. LAN is connected by Ethernet Cables, these are made up of coxial cable in different types. This, for a long time, was the only way to connect a computer as they used to have where they would connect to a mainframe and then a computer would be connected by Ethernet cable to the mainframe, making it a Local Area Network.<br />
<br />
==Wide Area Network==<br />
<br />
A Wide Area Network, or WAN, is made up of several computer networks connected together, often over the Internet. In most cases, the networks in WANs all belong to the same company or school. WANs are used to connect LANs and other types of networks together, so that users and computers in one location can communicate with users and computers in other locations. Many WANs are built for one particular organization and are private. Others, built by Internet service providers, provide connections from an organization's LAN to the Internet.<br />
<br />
The following image demonstrates how a wide area network is used in a computer network:<br />
<br />
[[File:17d1c375cab9c86e64c0b5987e1d6fc5109739c3.gif|x500px]]<br />
<br />
=Why do we network devices=<br />
==Benefits of Networking==<br />
* Sharing devices like printers saves money.<br />
* Site licences are likely to be cheaper than buying several standalone licences.<br />
* Files can easily be shared between users.<br />
* Network users can communicate by email.<br />
* Security is good, users cannot see other users' files unlike on stand-alone machines.<br />
* Data is easy to backup as all the data is stored on the file server.<br />
* Single password per user instead of per device.<br />
<br />
==Drawbacks of Networking==<br />
* Purchasing the network cabling and file servers can be expensive.<br />
* Managing a large network is complicated, requires training and a network manager usually needs to be employed.<br />
* If the file server breaks down the files on the file server become inaccessible.<br />
* Viruses can spread to other computers throughout a computer network.<br />
* There is a danger of hacking, particularly with WANs.<br />
* If there's a break in the network is down no work on computers can take place.<br />
<br />
=Revision Questions=<br />
<br />
===Question 1===<br />
<quiz display=simple><br />
{ what does CSMA/CD (carrier sense multiple access with collision detection) do when a collision is detected?<br />
|type ="()"}<br />
-stops sending data from all included devices and produces an error message<br />
||doesn't just just sending<br />
+stops sending data all devices wait a random ammount of time then retry<br />
||correct<br />
-keeps retrying until sent<br />
||incorrect this would not work and will stop the computer<br />
-data is transfered through the air instead<br />
|| this cannot be done with this protocol or possible in these systems<br />
</quiz><br />
<br />
===Question 2===<br />
<quiz display=simple><br />
{ Select all the benefits of networking: <br />
|type = "[]" }<br />
- All devices such as printers are independent to a machine which saves money<br />
|| Incorrect<br />
+ Files can easily be shared between users<br />
|| Correct <br />
+ Data is easy to backup as all the data is stored on the file server<br />
|| Correct <br />
- It's easier to travel<br />
||Leave your fridge open to stop global warming.<br />
+ Site licences are likely to be cheaper than buying several standalone licences<br />
||Correct<br />
</quiz><br />
<br />
===Question 3===<br />
<quiz display=simple><br />
{ Which of the following apply to a LAN? (Multiple Answers) <br />
|type="[]" } <br />
+ It is a form of networking that allows devices to communicate with each other and networks<br />
||This is correct.<br />
- It is connected via fibre optic<br />
||This is incorrect; it is connected via Ethernet<br />
+ It is connected via coaxial cables in the form of Ethernet<br />
||This is correct.<br />
+ It was the only way to connect a computer for a long time.<br />
||This is correct; they used to connect a mainframe to a computer via ethernet<br />
- It is a geographically remote network<br />
||This is incorrect; it is geographically confined.<br />
</quiz><br />
<br />
===Question 4===<br />
<quiz display=simple><br />
{ Define a Peer-peer network:<br />
|type = "()" }<br />
- Devices connected to a server to communicate with each other<br />
|| Incorrect<br />
+ Devices with equal status, with no servers connected <br />
|| Correct <br />
- Devices connected to a WAN <br />
|| Incorrect <br />
</quiz><br />
<br />
===Question 5===<br />
<quiz display=simple><br />
{ Which of the following are typically LAN connection medium?<br />
| type"[]" }<br />
- satellite link<br />
|| satellite link is ''not'' local area<br />
+ Ethernet Cable<br />
|| Correct<br />
- Fibre Optic cable<br />
|| No<br />
+ Wireless connection<br />
|| Correct<br />
</quiz><br />
<br />
===Question 6===<br />
<quiz display=simple><br />
{ What does LAN stand for?<br />
| type="[]" } <br />
- Logical active network.<br />
||Local area network was the correct answer.<br />
- Nothing<br />
||Bruh.<br />
+ Local area network.<br />
||Noice one.<br />
- Live area network.<br />
||Local area network was the correct answer.<br />
</quiz><br />
<br />
===Question 7===<br />
<quiz display=simple><br />
{ What does WAN stand for?<br />
| type="()" } <br />
<br />
- Wired Access Network<br />
|| Incorrect, it stands for Wide Area Network<br />
+ Wide Area Network<br />
|| Correct<br />
- Wireless Anatomy Network<br />
|| Incorrect, it stands for Wide Area Network<br />
- Wayne's Army Network<br />
|| '''NO!''' It stands for Wide Area Network<br />
<br />
</quiz><br />
<br />
===Question 30===<br />
<br />
<quiz display=simple><br />
<br />
{What are the communications media used in a WAN <br />
| type="[]" } <br />
+ Ethernet<br />
||Yes<br />
- USB.<br />
|| no <br />
+ Router.<br />
||yes<br />
+ Hub.<br />
||this is not wrong<br />
+ Switch <br />
|| incorrectn't<br />
- Coaxial cable<br />
</quiz><br />
<br />
===Question 9===<br />
<quiz display=simple><br />
{Which of these is not a drawback of using LAN? <br />
| type="()" }<br />
<br />
+ Saves money by sharing devices, like printers<br />
||Correct, this is a benefit<br />
- Managing a LAN is complicated<br />
||feedback for distractor<br />
- Buying network cabling and file servers can be expensive<br />
||feedback for distractor<br />
- Viruses can spread to other computers throughout the network<br />
||feedback for distractor<br />
</quiz><br />
<br />
===Question 10===<br />
<quiz display=simple><br />
{ State the advantages of a star topology over the bus topology.<br />
| type="[]" }<br />
+ Less chance of data collisions<br />
|| Correct<br />
+ Easier to detect faults<br />
|| Correct<br />
- Less cable overall is needed<br />
|| Incorrect<br />
- Easier to connect a computer or peripheral compared to a bus topology<br />
|| Incorrect<br />
+ No disruptions to the network when removing and connecting devices<br />
|| Correct<br />
</quiz><br />
<br />
===Question 11===<br />
<quiz display=simple><br />
{ Which of these is an benefit of networking? <br />
| type="()" } <br />
<br />
+ Files can easily be shared between users.<br />
|| Correct answer<br />
- Purchasing the network cabling and file servers can be expensive.<br />
|| The correct answer is "Files can easily be shared between users."<br />
- Managing a large network is complicated, requires training and a network manager usually needs to be employed.<br />
|| The correct answer is "Files can easily be shared between users."<br />
- Viruses can spread to other computers throughout a computer network.<br />
|| The correct answer is "Files can easily be shared between users."<br />
<br />
</quiz><br />
<br />
===Question 12===<br />
<quiz display=simple><br />
<br />
</quiz></div>000032680https://www.trccompsci.online/mediawiki/index.php?title=Network_Topology&diff=7650Network Topology2019-11-15T11:48:35Z<p>000032680: </p>
<hr />
<div>=Overview=<br />
===CraigNDave===<br />
<youtube>https://www.youtube.com/watch?v=Fzho2mQQEuU&list=PLCiOXwirraUDvVsza-xO2mMwW9QBIa_FG&index=0</youtube><br />
<br />
https://www.youtube.com/watch?v=Fzho2mQQEuU&list=PLCiOXwirraUDvVsza-xO2mMwW9QBIa_FG&index=0<br />
<br />
===Computer Science Tutor===<br />
<youtube>iiU06wkTAuY</youtube><br />
<br />
https://www.youtube.com/watch?v=iiU06wkTAuY&list=PL04uZ7242_M6O_6ITD6ncf7EonVHyBeCm&index=28<br />
<br />
===TRC PowerPoint===<br />
[https://studentthomrothac-my.sharepoint.com/:p:/g/personal/wayne_jones_thomroth_ac_uk/ESq8EvJEWYRLveCsprSXBAUBFKWSCXSoW70HqoR7Jv5GLg?e=VP2meV Network Topology]<br />
<br />
=Star Topology=<br />
[[File:StarNetwork svg.png|frame]]<br />
Nodes are connected to a host computer or hub that controls communication between devices. the hub or host computer regenerates any signal that it receives and passes it on. Only the intended recipient computer acts on the message.<br />
<br />
All nodes have independent connections to the host. A cable failure on one branch of the network will continue to function normally and the failure will be easy to isolate.<br />
<br />
{| class="wikitable sortable"<br />
|-<br />
! Advantages !! Disadvantages<br />
|-<br />
| · Adding new devices is easy and doesn't disrupt the rest of the network.|| · It requires a lot of cables.<br />
|-<br />
| · There are no data collisions.|| · It is expensive to install.<br />
|-<br />
| · There is less traffic on the network.|| · Needs professionals to maintain and up keep.<br />
|-<br />
| · A cable failure on one branch of the network will be easy to isolate.|| <br />
|}<br />
<br><br />
<br />
=Bus Topology=<br />
[[File:BusNetwork svg.png|frame]]<br />
When the bus (or line) topology is used each workstation is connected to a single cable (or backbone) which links all of the workstations.<br />
<br />
The servers are connected to the main bus for data distribution to all the workstations.<br />
<br />
Data can be transmitted in either directed along the main cable and workstations can communicate with other workstations.<br />
<br />
A range of peripherals can also be connected to the main bus for shared usage. This could be a printer for example.<br />
<br />
{| class="wikitable"<br />
|-<br />
! Advantages !! Disadvantages<br />
|-<br />
<br />
| ·Is cheaper to install as it used the least cable as the cost of network cabling (particular fibre optic), and the cost of the network cable installation can be significant|| ·If there is heavy traffic the system performance will fall off dramatically<br />
|- <br />
| . || ·Data collisions due to shared cable<br />
|- <br />
| . || .Problems can be difficult to isolate<br />
|}<br />
<br><br />
<br />
==Data Collisions - CSMA/CD==<br />
CSMA/CD stands for Carrier Sense Multiple Access/Collision Detection. It is the protocol for carrier transmission access in ethernet networks. If two devices try to send a frame at the same time, a collision occurs and the frames are discarded. Each devices then waits a random amount of time and retries until the transmission is successfully sent.<br />
<br />
==Logical Bus Topology==<br />
A network could be wired using a star topology, but could act like a bus topology if all data traffic is sent to all machines.<br />
<br />
=Revision Questions=<br />
<br />
===Question 1===<br />
<quiz display=simple><br />
<br />
</quiz><br />
<br />
===Question 2===<br />
<quiz display=simple><br />
{ What is bus Topology?<br />
| type="()" } <br />
- Multiple Nodes are connected to a host computer<br />
|| No<br />
+ Each computer is connected to 1 main linear cable.<br />
||<br />
- Its the customer service in the bus station<br />
|| Not that bus.<br />
- A bus prevents data collisions.<br />
|| WRONG<br />
- Your closest bus stop<br />
|| NO<br />
- A host computer that controls all devices<br />
|| Bad<br />
</quiz><br />
<br />
===Question 3===<br />
<quiz display=simple><br />
{In a bus topology, all devices use different cables for connection.<br />
|type="()"}<br />
+ False.<br />
- True.<br />
</quiz><br />
<br />
===Question 4===<br />
<quiz display=simple><br />
{ State one advantage of the star topology over the bus topology network: <br />
|type = () }<br />
- Uses the least amount of cables<br />
||Incorrect: All nodes are connected by their own wire to the hub<br />
+ No data collision<br />
||Correct: Because all nodes don't use one wire for the backbone of transferring data<br />
- Is the cheapest to make<br />
||Incorrect: Requires more wires which is more expensive<br />
- Does not require to install a hub or switch<br />
||Incorrect: The hub is the central point of which all nodes connect to <br />
</quiz><br />
<br />
===Question 5===<br />
<quiz display=simple><br />
{ What are the differences between a switch and a hub?<br />
| type="[]" } <br />
- A hub sends signals to the switch.<br />
|| No<br />
+ Switches maintain a list of devices that it has encountered before.<br />
|| If a device is on the list and is the intended recipient of a message, the message will only be transmitted to the device.<br />
- A hub contains all of your favourite shows for only £9.99 paid bi-monthly, what a steal.<br />
|| Not a hub.<br />
- A switch prevents data collisions.<br />
|| Both hubs and switches prevent data collisions.<br />
+ A hub will transmit data to all devices<br />
|| Yes<br />
- A switch will '''never''' transmit to all devices<br />
|| A switch will transmit to all devices if it hasn't ever encountered the intended recipient of the data.<br />
</quiz><br />
<br />
===Question 6===<br />
<quiz display=simple><br />
{ What is a star topology?<br />
| type="[]" } <br />
- All nodes are connected to each other.<br />
||That is a mesh topology<br />
- All nodes are connected by one wire.<br />
||That is a bus topology.<br />
+ All nodes are connected to a central switch or hub.<br />
||Epic.<br />
- The nodes are arranged in a star shape.<br />
||Bruh.<br />
</quiz><br />
<br />
===Question 7===<br />
<quiz display=simple><br />
<br />
{ What is a bus topology?<br />
| type="()" } <br />
<br />
- Uses may cables to transmit data<br />
|| This is incorrect, a bus topology uses a single main cable as a backbone<br />
+ Uses one main cable as a backbone to transmit data<br />
|| This is correct<br />
- Connected devices in a network where each workstation has a dedicated cable to a central computer or switch<br />
|| This is a star topology. A bus network uses one main cable as a backbone to transmit data<br />
- A wire with a bus in it<br />
|| This is very wrong, a bus topology uses a single main cable as a backbone to transmit data<br />
<br />
<br />
</quiz><br />
<br />
===Question 8===<br />
<quiz display=simple><br />
{bus topologies have a central area to connect all of the devices<br />
|type="()"}<br />
- TRUE. ⋆<br />
|| no<br />
+ FALSE.<br />
||this is actually star <br />
</quiz><br />
<br />
===Question 9===<br />
<quiz display=simple><br />
<br />
</quiz><br />
<br />
===Question 10===<br />
<quiz display=simple><br />
<br />
{<br />
<br />
</quiz><br />
<br />
===Question 11===<br />
<quiz display=simple><br />
<br />
{Which one of these is an advantage of star topologies?<br />
| type="()" }<br />
<br />
+ Adding new devices is easy and doesn't disrupt the rest of the network.<br />
|| Correct answer<br />
- It requires a lot of cables.<br />
|| The correct answer was "Adding new devices is easy and doesn't disrupt the rest of the network."<br />
- It is expensive to install.<br />
|| The correct answer was "Adding new devices is easy and doesn't disrupt the rest of the network."<br />
- Needs professionals to maintain and up keep.<br />
|| The correct answer was "Adding new devices is easy and doesn't disrupt the rest of the network."<br />
<br />
</quiz><br />
<br />
===Question 12===<br />
<quiz display=simple><br />
<br />
</quiz></div>000032680https://www.trccompsci.online/mediawiki/index.php?title=Network_Topology&diff=7642Network Topology2019-11-15T11:45:29Z<p>000032680: /* Question 4 */</p>
<hr />
<div>=Overview=<br />
===CraigNDave===<br />
<youtube>https://www.youtube.com/watch?v=Fzho2mQQEuU&list=PLCiOXwirraUDvVsza-xO2mMwW9QBIa_FG&index=0</youtube><br />
<br />
https://www.youtube.com/watch?v=Fzho2mQQEuU&list=PLCiOXwirraUDvVsza-xO2mMwW9QBIa_FG&index=0<br />
<br />
===Computer Science Tutor===<br />
<youtube>iiU06wkTAuY</youtube><br />
<br />
https://www.youtube.com/watch?v=iiU06wkTAuY&list=PL04uZ7242_M6O_6ITD6ncf7EonVHyBeCm&index=28<br />
<br />
===TRC PowerPoint===<br />
[https://studentthomrothac-my.sharepoint.com/:p:/g/personal/wayne_jones_thomroth_ac_uk/ESq8EvJEWYRLveCsprSXBAUBFKWSCXSoW70HqoR7Jv5GLg?e=VP2meV Network Topology]<br />
<br />
=Star Topology=<br />
[[File:StarNetwork svg.png|frame]]<br />
Nodes are connected to a host computer or hub that controls communication between devices. the hub or host computer regenerates any signal that it receives and passes it on. Only the intended recipient computer acts on the message.<br />
<br />
All nodes have independent connections to the host. A cable failure on one branch of the network will continue to function normally and the failure will be easy to isolate.<br />
<br />
{| class="wikitable sortable"<br />
|-<br />
! Advantages !! Disadvantages<br />
|-<br />
| · Adding new devices is easy and doesn't disrupt the rest of the network.|| · It requires a lot of cables.<br />
|-<br />
| · There are no data collisions.|| · It is expensive to install.<br />
|-<br />
| · There is less traffic on the network.|| · Needs professionals to maintain and up keep.<br />
|-<br />
| · A cable failure on one branch of the network will be easy to isolate.|| <br />
|}<br />
<br><br />
<br />
=Bus Topology=<br />
[[File:BusNetwork svg.png|frame]]<br />
When the bus (or line) topology is used each workstation is connected to a single cable (or backbone) which links all of the workstations.<br />
<br />
The servers are connected to the main bus for data distribution to all the workstations.<br />
<br />
Data can be transmitted in either directed along the main cable and workstations can communicate with other workstations.<br />
<br />
A range of peripherals can also be connected to the main bus for shared usage. This could be a printer for example.<br />
<br />
{| class="wikitable"<br />
|-<br />
! Advantages !! Disadvantages<br />
|-<br />
<br />
| ·Is cheaper to install as it used the least cable as the cost of network cabling (particular fibre optic), and the cost of the network cable installation can be significant|| ·If there is heavy traffic the system performance will fall off dramatically<br />
|- <br />
| . || ·Data collisions due to shared cable<br />
|- <br />
| . || .Problems can be difficult to isolate<br />
|}<br />
<br><br />
<br />
==Data Collisions - CSMA/CD==<br />
CSMA/CD stands for Carrier Sense Multiple Access/Collision Detection. It is the protocol for carrier transmission access in ethernet networks. If two devices try to send a frame at the same time, a collision occurs and the frames are discarded. Each devices then waits a random amount of time and retries until the transmission is successfully sent.<br />
<br />
==Logical Bus Topology==<br />
A network could be wired using a star topology, but could act like a bus topology if all data traffic is sent to all machines.<br />
<br />
=Revision Questions=<br />
<br />
===Question 1===<br />
<quiz display=simple><br />
<br />
</quiz><br />
<br />
===Question 2===<br />
<quiz display=simple><br />
{ What is bus Topology?<br />
| type="()" } <br />
- Multiple Nodes are connected to a host computer<br />
|| No<br />
+ Each computer is connected to 1 main linear cable.<br />
||<br />
- Its the customer service in the bus station<br />
|| Not that bus.<br />
- A bus prevents data collisions.<br />
|| WRONG<br />
- Your closest bus stop<br />
|| NO<br />
- A host computer that controls all devices<br />
|| Bad<br />
</quiz><br />
<br />
===Question 3===<br />
<quiz display=simple><br />
{In a bus topology, all devices use different cables for connection.<br />
|type="()"}<br />
+ False.<br />
- True.<br />
</quiz><br />
<br />
===Question 4===<br />
<quiz display=simple><br />
{ State one advantage of the star topology over the bus topology network: <br />
|type = () }<br />
- Uses the least amount of cables<br />
||Incorrect: All nodes are connected by their own wire to the hub<br />
+ No data collision<br />
||Correct: Because all nodes don't use one wire for the backbone of transferring data<br />
- Is the cheapest to make<br />
||Incorrect: Requires more wires which is more expensive<br />
- Does not require to install a hub or switch<br />
||Incorrect: The hub is the central point of which all nodes connect to <br />
</quiz><br />
<br />
===Question 5===<br />
<quiz display=simple><br />
{ What are the differences between a switch and a hub?<br />
| type="[]" } <br />
- A hub sends signals to the switch.<br />
|| No<br />
+ Switches maintain a list of devices that it has encountered before.<br />
|| If a device is on the list and is the intended recipient of a message, the message will only be transmitted to the device.<br />
- A hub contains all of your favourite shows for only £9.99 paid bi-monthly, what a steal.<br />
|| Not a hub.<br />
- A switch prevents data collisions.<br />
|| Both hubs and switches prevent data collisions.<br />
+ A hub will transmit data to all devices<br />
|| Yes<br />
- A switch will '''never''' transmit to all devices<br />
|| A switch will transmit to all devices if it hasn't ever encountered the intended recipient of the data.<br />
</quiz><br />
<br />
===Question 6===<br />
<quiz display=simple><br />
{ What is a star topology?<br />
| type="[]" } <br />
- All nodes are connected to each other.<br />
||That is a mesh topology<br />
- All nodes are connected by one wire.<br />
||That is a bus topology.<br />
+ All nodes are connected to a central switch or hub.<br />
||Epic.<br />
- The nodes are arranged in a star shape.<br />
||Bruh.<br />
</quiz><br />
<br />
===Question 7===<br />
<quiz display=simple><br />
<br />
{ What is a bus topology?<br />
| type="()" } <br />
<br />
- Uses may cables to transmit data<br />
|| This is incorrect, a bus topology uses a single main cable as a backbone<br />
+ Uses one main cable as a backbone to transmit data<br />
|| This is correct<br />
- Connected devices in a network where each workstation has a dedicated cable to a central computer or switch<br />
|| This is a star topology. A bus network uses one main cable as a backbone to transmit data<br />
- A wire with a bus in it<br />
|| This is very wrong, a bus topology uses a single main cable as a backbone to transmit data<br />
<br />
<br />
</quiz><br />
<br />
===Question 8===<br />
<quiz display=simple><br />
{bus topologies have a central area to connect all of the devices<br />
|type="()"}<br />
- TRUE. ⋆<br />
|| no<br />
+ FALSE.<br />
||this is actually star <br />
</quiz><br />
<br />
===Question 9===<br />
<quiz display=simple><br />
<br />
</quiz><br />
<br />
===Question 10===<br />
<quiz display=simple><br />
<br />
</quiz><br />
<br />
===Question 11===<br />
<quiz display=simple><br />
<br />
{Which one of these is an advantage of star topologies?<br />
| type="()" }<br />
<br />
+ Adding new devices is easy and doesn't disrupt the rest of the network.<br />
|| Correct answer<br />
- It requires a lot of cables.<br />
|| The correct answer was "Adding new devices is easy and doesn't disrupt the rest of the network."<br />
- It is expensive to install.<br />
|| The correct answer was "Adding new devices is easy and doesn't disrupt the rest of the network."<br />
- Needs professionals to maintain and up keep.<br />
|| The correct answer was "Adding new devices is easy and doesn't disrupt the rest of the network."<br />
<br />
</quiz><br />
<br />
===Question 12===<br />
<quiz display=simple><br />
<br />
</quiz></div>000032680https://www.trccompsci.online/mediawiki/index.php?title=Network_Topology&diff=7641Network Topology2019-11-15T11:45:06Z<p>000032680: /* Question 4 */</p>
<hr />
<div>=Overview=<br />
===CraigNDave===<br />
<youtube>https://www.youtube.com/watch?v=Fzho2mQQEuU&list=PLCiOXwirraUDvVsza-xO2mMwW9QBIa_FG&index=0</youtube><br />
<br />
https://www.youtube.com/watch?v=Fzho2mQQEuU&list=PLCiOXwirraUDvVsza-xO2mMwW9QBIa_FG&index=0<br />
<br />
===Computer Science Tutor===<br />
<youtube>iiU06wkTAuY</youtube><br />
<br />
https://www.youtube.com/watch?v=iiU06wkTAuY&list=PL04uZ7242_M6O_6ITD6ncf7EonVHyBeCm&index=28<br />
<br />
===TRC PowerPoint===<br />
[https://studentthomrothac-my.sharepoint.com/:p:/g/personal/wayne_jones_thomroth_ac_uk/ESq8EvJEWYRLveCsprSXBAUBFKWSCXSoW70HqoR7Jv5GLg?e=VP2meV Network Topology]<br />
<br />
=Star Topology=<br />
[[File:StarNetwork svg.png|frame]]<br />
Nodes are connected to a host computer or hub that controls communication between devices. the hub or host computer regenerates any signal that it receives and passes it on. Only the intended recipient computer acts on the message.<br />
<br />
All nodes have independent connections to the host. A cable failure on one branch of the network will continue to function normally and the failure will be easy to isolate.<br />
<br />
{| class="wikitable sortable"<br />
|-<br />
! Advantages !! Disadvantages<br />
|-<br />
| · Adding new devices is easy and doesn't disrupt the rest of the network.|| · It requires a lot of cables.<br />
|-<br />
| · There are no data collisions.|| · It is expensive to install.<br />
|-<br />
| · There is less traffic on the network.|| · Needs professionals to maintain and up keep.<br />
|-<br />
| · A cable failure on one branch of the network will be easy to isolate.|| <br />
|}<br />
<br><br />
<br />
=Bus Topology=<br />
[[File:BusNetwork svg.png|frame]]<br />
When the bus (or line) topology is used each workstation is connected to a single cable (or backbone) which links all of the workstations.<br />
<br />
The servers are connected to the main bus for data distribution to all the workstations.<br />
<br />
Data can be transmitted in either directed along the main cable and workstations can communicate with other workstations.<br />
<br />
A range of peripherals can also be connected to the main bus for shared usage. This could be a printer for example.<br />
<br />
{| class="wikitable"<br />
|-<br />
! Advantages !! Disadvantages<br />
|-<br />
<br />
| ·Is cheaper to install as it used the least cable as the cost of network cabling (particular fibre optic), and the cost of the network cable installation can be significant|| ·If there is heavy traffic the system performance will fall off dramatically<br />
|- <br />
| . || ·Data collisions due to shared cable<br />
|- <br />
| . || .Problems can be difficult to isolate<br />
|}<br />
<br><br />
<br />
==Data Collisions - CSMA/CD==<br />
CSMA/CD stands for Carrier Sense Multiple Access/Collision Detection. It is the protocol for carrier transmission access in ethernet networks. If two devices try to send a frame at the same time, a collision occurs and the frames are discarded. Each devices then waits a random amount of time and retries until the transmission is successfully sent.<br />
<br />
==Logical Bus Topology==<br />
A network could be wired using a star topology, but could act like a bus topology if all data traffic is sent to all machines.<br />
<br />
=Revision Questions=<br />
<br />
===Question 1===<br />
<quiz display=simple><br />
<br />
</quiz><br />
<br />
===Question 2===<br />
<quiz display=simple><br />
{ What is bus Topology?<br />
| type="()" } <br />
- Multiple Nodes are connected to a host computer<br />
|| No<br />
+ Each computer is connected to 1 main linear cable.<br />
||<br />
- Its the customer service in the bus station<br />
|| Not that bus.<br />
- A bus prevents data collisions.<br />
|| WRONG<br />
- Your closest bus stop<br />
|| NO<br />
- A host computer that controls all devices<br />
|| Bad<br />
</quiz><br />
<br />
===Question 3===<br />
<quiz display=simple><br />
{In a bus topology, all devices use different cables for connection.<br />
|type="()"}<br />
+ False.<br />
- True.<br />
</quiz><br />
<br />
===Question 4===<br />
<quiz display=simple><br />
{ State one advantage of the star topology over the bus topology network: <br />
|type = () }<br />
- Uses the least amount of cables<br />
||Incorrect: All nodes are connected by their own wire to the hub<br />
+ No data collision<br />
||Correct: Because all nodes don't use one wire for the backbone of transfering data<br />
- Is the cheapest to make<br />
||Incorrect: Requires more wires which is more expensive<br />
- Does not require to install a hub or switch<br />
||Incorrect: The hub is the central point of which all nodes connect to <br />
</quiz><br />
<br />
===Question 5===<br />
<quiz display=simple><br />
{ What are the differences between a switch and a hub?<br />
| type="[]" } <br />
- A hub sends signals to the switch.<br />
|| No<br />
+ Switches maintain a list of devices that it has encountered before.<br />
|| If a device is on the list and is the intended recipient of a message, the message will only be transmitted to the device.<br />
- A hub contains all of your favourite shows for only £9.99 paid bi-monthly, what a steal.<br />
|| Not a hub.<br />
- A switch prevents data collisions.<br />
|| Both hubs and switches prevent data collisions.<br />
+ A hub will transmit data to all devices<br />
|| Yes<br />
- A switch will '''never''' transmit to all devices<br />
|| A switch will transmit to all devices if it hasn't ever encountered the intended recipient of the data.<br />
</quiz><br />
<br />
===Question 6===<br />
<quiz display=simple><br />
{ What is a star topology?<br />
| type="[]" } <br />
- All nodes are connected to each other.<br />
||That is a mesh topology<br />
- All nodes are connected by one wire.<br />
||That is a bus topology.<br />
+ All nodes are connected to a central switch or hub.<br />
||Epic.<br />
- The nodes are arranged in a star shape.<br />
||Bruh.<br />
</quiz><br />
<br />
===Question 7===<br />
<quiz display=simple><br />
<br />
{ What is a bus topology?<br />
| type="()" } <br />
<br />
- Uses may cables to transmit data<br />
|| This is incorrect, a bus topology uses a single main cable as a backbone<br />
+ Uses one main cable as a backbone to transmit data<br />
|| This is correct<br />
- Connected devices in a network where each workstation has a dedicated cable to a central computer or switch<br />
|| This is a star topology. A bus network uses one main cable as a backbone to transmit data<br />
- A wire with a bus in it<br />
|| This is very wrong, a bus topology uses a single main cable as a backbone to transmit data<br />
<br />
<br />
</quiz><br />
<br />
===Question 8===<br />
<quiz display=simple><br />
{bus topologies have a central area to connect all of the devices<br />
|type="()"}<br />
- TRUE. ⋆<br />
|| no<br />
+ FALSE.<br />
||this is actually star <br />
</quiz><br />
<br />
===Question 9===<br />
<quiz display=simple><br />
<br />
</quiz><br />
<br />
===Question 10===<br />
<quiz display=simple><br />
<br />
</quiz><br />
<br />
===Question 11===<br />
<quiz display=simple><br />
<br />
{Which one of these is an advantage of star topologies?<br />
| type="()" }<br />
<br />
+ Adding new devices is easy and doesn't disrupt the rest of the network.<br />
|| Correct answer<br />
- It requires a lot of cables.<br />
|| The correct answer was "Adding new devices is easy and doesn't disrupt the rest of the network."<br />
- It is expensive to install.<br />
|| The correct answer was "Adding new devices is easy and doesn't disrupt the rest of the network."<br />
- Needs professionals to maintain and up keep.<br />
|| The correct answer was "Adding new devices is easy and doesn't disrupt the rest of the network."<br />
<br />
</quiz><br />
<br />
===Question 12===<br />
<quiz display=simple><br />
<br />
</quiz></div>000032680https://www.trccompsci.online/mediawiki/index.php?title=Network_Topology&diff=7636Network Topology2019-11-15T11:41:36Z<p>000032680: </p>
<hr />
<div>=Overview=<br />
===CraigNDave===<br />
<youtube>https://www.youtube.com/watch?v=Fzho2mQQEuU&list=PLCiOXwirraUDvVsza-xO2mMwW9QBIa_FG&index=0</youtube><br />
<br />
https://www.youtube.com/watch?v=Fzho2mQQEuU&list=PLCiOXwirraUDvVsza-xO2mMwW9QBIa_FG&index=0<br />
<br />
===Computer Science Tutor===<br />
<youtube>iiU06wkTAuY</youtube><br />
<br />
https://www.youtube.com/watch?v=iiU06wkTAuY&list=PL04uZ7242_M6O_6ITD6ncf7EonVHyBeCm&index=28<br />
<br />
===TRC PowerPoint===<br />
[https://studentthomrothac-my.sharepoint.com/:p:/g/personal/wayne_jones_thomroth_ac_uk/ESq8EvJEWYRLveCsprSXBAUBFKWSCXSoW70HqoR7Jv5GLg?e=VP2meV Network Topology]<br />
<br />
=Star Topology=<br />
[[File:StarNetwork svg.png|frame]]<br />
Nodes are connected to a host computer or hub that controls communication between devices. the hub or host computer regenerates any signal that it receives and passes it on. Only the intended recipient computer acts on the message.<br />
<br />
All nodes have independent connections to the host. A cable failure on one branch of the network will continue to function normally and the failure will be easy to isolate.<br />
<br />
{| class="wikitable sortable"<br />
|-<br />
! Advantages !! Disadvantages<br />
|-<br />
| · Adding new devices is easy and doesn't disrupt the rest of the network.|| · It requires a lot of cables.<br />
|-<br />
| · There are no data collisions.|| · It is expensive to install.<br />
|-<br />
| · There is less traffic on the network.|| · Needs professionals to maintain and up keep.<br />
|-<br />
| · A cable failure on one branch of the network will be easy to isolate.|| <br />
|}<br />
<br><br />
<br />
=Bus Topology=<br />
[[File:BusNetwork svg.png|frame]]<br />
When the bus (or line) topology is used each workstation is connected to a single cable (or backbone) which links all of the workstations.<br />
<br />
The servers are connected to the main bus for data distribution to all the workstations.<br />
<br />
Data can be transmitted in either directed along the main cable and workstations can communicate with other workstations.<br />
<br />
A range of peripherals can also be connected to the main bus for shared usage. This could be a printer for example.<br />
<br />
{| class="wikitable"<br />
|-<br />
! Advantages !! Disadvantages<br />
|-<br />
<br />
| ·Is cheaper to install as it used the least cable as the cost of network cabling (particular fibre optic), and the cost of the network cable installation can be significant|| ·If there is heavy traffic the system performance will fall off dramatically<br />
|- <br />
| . || ·Data collisions due to shared cable<br />
|- <br />
| . || .Problems can be difficult to isolate<br />
|}<br />
<br><br />
<br />
==Data Collisions - CSMA/CD==<br />
CSMA/CD stands for Carrier Sense Multiple Access/Collision Detection. It is the protocol for carrier transmission access in ethernet networks. If two devices try to send a frame at the same time, a collision occurs and the frames are discarded. Each devices then waits a random amount of time and retries until the transmission is successfully sent.<br />
<br />
==Logical Bus Topology==<br />
A network could be wired using a star topology, but could act like a bus topology if all data traffic is sent to all machines.<br />
<br />
=Revision Questions=<br />
<br />
===Question 1===<br />
<quiz display=simple><br />
<br />
</quiz><br />
<br />
===Question 2===<br />
<quiz display=simple><br />
{ What is bus Topology?<br />
| type="()" } <br />
- Multiple Nodes are connected to a host computer<br />
|| No<br />
+ Each computer is connected to 1 main linear cable.<br />
||<br />
- Its the customer service in the bus station<br />
|| Not that bus.<br />
- A bus prevents data collisions.<br />
|| WRONG<br />
- Your closest bus stop<br />
|| NO<br />
- A host computer that controls all devices<br />
|| Bad<br />
</quiz><br />
<br />
===Question 3===<br />
<quiz display=simple><br />
{In a bus topology, all devices use different cables for connection.<br />
|type="()"}<br />
+ False.<br />
- True.<br />
</quiz><br />
<br />
===Question 4===<br />
<quiz display=simple><br />
{ State one advantage of the star topology over the bus topology network: <br />
|type = () }<br />
- Uses the least amount of cables<br />
||Incorrect<br />
+ No data collision<br />
||Correct<br />
- Is the cheapest to make<br />
||Incorrect<br />
- Does not require to install a hub or switch<br />
||Incorrect<br />
</quiz><br />
<br />
===Question 5===<br />
<quiz display=simple><br />
{ What are the differences between a switch and a hub?<br />
| type="[]" } <br />
- A hub sends signals to the switch.<br />
|| No<br />
+ Switches maintain a list of devices that it has encountered before.<br />
|| If a device is on the list and is the intended recipient of a message, the message will only be transmitted to the device.<br />
- A hub contains all of your favourite shows for only £9.99 paid bi-monthly, what a steal.<br />
|| Not a hub.<br />
- A switch prevents data collisions.<br />
|| Both hubs and switches prevent data collisions.<br />
+ A hub will transmit data to all devices<br />
|| Yes<br />
- A switch will '''never''' transmit to all devices<br />
|| A switch will transmit to all devices if it hasn't ever encountered the intended recipient of the data.<br />
</quiz><br />
<br />
===Question 6===<br />
<quiz display=simple><br />
{ What is a star topology?<br />
| type="[]" } <br />
- All nodes are connected to each other.<br />
||That is a mesh topology<br />
- All nodes are connected by one wire.<br />
||That is a bus topology.<br />
+ All nodes are connected to a central switch or hub.<br />
||Epic.<br />
- The nodes are arranged in a star shape.<br />
||Bruh.<br />
</quiz><br />
<br />
===Question 7===<br />
<quiz display=simple><br />
<br />
{ What is a bus topology?<br />
| type="()" } <br />
<br />
- Uses may cables to transmit data<br />
|| This is incorrect, a bus topology uses a single main cable as a backbone<br />
+ Uses one main cable as a backbone to transmit data<br />
|| This is correct<br />
- Connected devices in a network where each workstation has a dedicated cable to a central computer or switch<br />
|| This is a star topology. A bus network uses one main cable as a backbone to transmit data<br />
- A wire with a bus in it<br />
|| This is very wrong, a bus topology uses a single main cable as a backbone to transmit data<br />
<br />
<br />
</quiz><br />
<br />
===Question 8===<br />
<quiz display=simple><br />
{bus topologies have a central area to connect all of the devices<br />
|type="()"}<br />
- TRUE. ⋆<br />
|| no<br />
+ FALSE.<br />
||this is actually star <br />
</quiz><br />
<br />
===Question 9===<br />
<quiz display=simple><br />
<br />
</quiz><br />
<br />
===Question 10===<br />
<quiz display=simple><br />
<br />
</quiz><br />
<br />
===Question 11===<br />
<quiz display=simple><br />
<br />
{Which one of these is an advantage of star topologies?<br />
| type="()" }<br />
<br />
+ Adding new devices is easy and doesn't disrupt the rest of the network.<br />
|| Correct answer<br />
- It requires a lot of cables.<br />
|| The correct answer was "Adding new devices is easy and doesn't disrupt the rest of the network."<br />
- It is expensive to install.<br />
|| The correct answer was "Adding new devices is easy and doesn't disrupt the rest of the network."<br />
- Needs professionals to maintain and up keep.<br />
|| The correct answer was "Adding new devices is easy and doesn't disrupt the rest of the network."<br />
<br />
</quiz><br />
<br />
===Question 12===<br />
<quiz display=simple><br />
<br />
</quiz></div>000032680https://www.trccompsci.online/mediawiki/index.php?title=Sound&diff=7380Sound2019-10-16T09:12:48Z<p>000032680: /* Revision Questions */</p>
<hr />
<div>=Overview=<br />
===Computer Science Tutor===<br />
<youtube>HlOTuCFtuV8</youtube><br />
<br />
https://www.youtube.com/watch?v=HlOTuCFtuV8&list=PL04uZ7242_M6O_6ITD6ncf7EonVHyBeCm&index=9<br />
<br />
===TRC PowerPoint===<br />
[https://studentthomrothac-my.sharepoint.com/:p:/g/personal/wayne_jones_thomroth_ac_uk/Ebzu5zwPN85NnUj6124W7AgBMe8qBBKxLOG0yw3HP20_hg?e=N811yn Sound]<br />
<br />
==Converting Analogue to Digital Sound==<br />
<br />
The following image demonstrates how sound files are created when they are inputted through devices such as a microphone:<br />
<br />
[[File:600px-Analogue_Digital_Conversion.png]]<br />
<br />
further explanation:<br />
<br />
<youtube>https://www.youtube.com/watch?v=VyqGzUbTphs&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4&index=1</youtube><br />
<br />
https://www.youtube.com/watch?v=VyqGzUbTphs&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4&index=1<br />
<br />
==Representing Sound==<br />
<br />
To store sound, a digitizer is needed to convert the analogue sound into digital sound. An analogue to digital converter carries out these conversions. 16 bit ADC is enough for CD quality sound. For High-Res audio, you can get audio files that are at 24 bit.<br />
<br />
[[File:Sound Samples.gif]]<br />
<br />
====Sampling Rate====<br />
<br />
The sampling rate or frequency is the number of samples taken per second. It is measured in hertz (Hz). The higher the sampling rate the more accurate the representation of the sound. But the higher the sampling rate, the bigger the file size will be as there will be more data the is being stored<br />
<br />
[[File:Sound Sampling Rate.jpg|200px]]<br />
<br />
====Sampling Resolution====<br />
<br />
The sampling resolution is the number of bits assigned to each sample. The number of bits assigned allows for a wider range of sounds to be displayed. For example, if only one bit is used it can only be either 1 or 0, giving an option of only two different sounds, where as if 8 bits are used there are a possible 255 different sounds that can be recorded and then replayed. In a way, your PC bleeper speaker is one bit as it only produces one tone when there is a error on your computer and then your actual speakers that you listen to music to will be 8 bit sound as you can play 255 different sounds on it.<br />
<br />
====Additional Video====<br />
<br />
<youtube>https://www.youtube.com/watch?v=v7RwEnirp7I&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=v7RwEnirp7I&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
<br />
====Calculating File Size====<br />
A sound is sampled at 5kHz (5000 Hz) and the sample resolution is 16 bits:<br />
<br />
# There is 5000 samples per second & each sample is 2 byte (16 bits)<br />
# 1 second of sound will be 5000 x 2 = 10,000 Bytes<br />
# 10 seconds of sound will be 5000 x 20 = 100,000 Bytes<br />
<br />
<youtube>https://www.youtube.com/watch?v=al5HsKIRhQw&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=al5HsKIRhQw&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
<br />
====Sampling Process====<br />
<br />
Pulse Amplitude Modulation (PAM) is the process which samples analogue signals and produces electrical pulses of height proportional to the signal's original amplitude.<br />
<br />
Pulse Code Modulation (PCM) is the process of coding sampled analogue signals by recording the height of each sample in binary.<br />
PCM pulses can then be encoded in binary form.<br />
<br />
== Nyquist's Theorem ==<br />
<br />
In 1928 Harry Nyquist found that in order to sample any sound at a similar quality to how it is in real life, you must use a sampling rate at double the frequency of the original sound. The result will be the closest possible to the original sound, because recording at double the frequency allows for all of the changes in the sound such as pitch to be captured digitally at a high quality.<br />
<br />
== MIDI Data ==<br />
<br />
MIDI stands for Musical Instrument Digital Interface.<br />
<br />
MIDI does a completely different approach to other sound recording methods. Instead of recording sound and then storing it in a digital format, It actually writes out a set of instructions which can be used to synthesize the sound that is listened to.<br />
This relies solely on pre-recorded digital samples and synthesized samples of sounds created by different instruments.<br />
<br />
The advantages of using MIDI instead of conventional recording methods is that firstly, it is a fraction of the size of a digital recorded version, it is easily edited or manipulated and notes can be passed to a different instrument and so the attributes of each note can be altered.<br />
<br />
<youtube>https://www.youtube.com/watch?v=AvqP3BhO0d8&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=AvqP3BhO0d8&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
<br />
== Audio Compression ==<br />
<br />
Audio compression is used to lower the storage space that a digital sound file takes up by removing sounds that humans won't be able to pick up listening to it. For example, in a song with guitar and drums, when there is a loud drum hit, the guitar will often be drowned out and could even become completely inaudible, so this data is removed to reduce the size of the audio file so it takes up less storage space, which is useful for devices like phones with a limited storage space. It is also useful for streaming music as it reduces the chance of the music buffering by reducing the amount of data which needs to be sent allowing for smoother more consistent listening.<br />
<br />
== Audio Streaming ==<br />
<br />
Audio streaming is a way in which audio/sound is broadcast to a user. It allows a user to listen to an audio file or watch a video without downloading the whole file, they only download a bit at a time... Which is the buffer.<br />
<br />
Audio Streaming has a delayed start in order to allow it to buffer, it also plays sound from the buffer and has seamless play unless connection to the host is lost. Audio Streaming saves space on the hard drive since the file is no longer required to be downloaded on the device for it be viewed, Which also means piracy is reduced.<br />
<br />
Audio streaming is so widely used and respected because of its usefulness. Before Audio Streaming was around, it could take you quite a while to listen to music/sound since you would have to download the whole file. Whereas Audio Streaming simply gives you the data that you need at that specific time and downloads the next when you need it. It does this simply by holding the data in the buffer.<br />
<br />
== Synthesising Sound ==<br />
<br />
Sound can be synthesised with MIDI (Musical Instrument Digital Interface), which records information about each note - such as duration, pitch, tempo, instrument and volume - and recreates that note when played. When using MIDI it is hard to replicate the proper sound as it would have to be played through note by note and would be a synthetic sound, in some cases it's good like in pop music but in other cases usually not. A MIDI link can hold up to 16 channels of information which can be routed to a seperate device for each channel.<br />
<br />
<br />
=Revision Questions=<br />
<br />
<quiz><br />
{ How many bits is enough for CD quality audio? <br />
| type="()" }<br />
+ 16 bit<br />
||Correct, you only need 16 bits to achieve CD quality audio.<br />
- 24 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
- 32 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
- 64 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
<br />
{ According to Nyquist's Theorem, what should our sampling rate be?<br />
| type="()" }<br />
- Half the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
- The same as the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
+ Double the original rate.<br />
||Correct, sampling at double the rate of the original audio will achieve the closest match.<br />
- Triple the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
<br />
{ Which of the following are examples of audio file formats?<br />
| type="[]" }<br />
+ .mp3<br />
||Correct, mp3 represents ''MPEG-1 or MPEG-2 Audio Layer III'' audio file format.<br />
+ .wav<br />
||Correct, wav represents ''Waveform Audio File Format''.<br />
- .bmp<br />
||Incorrect, bmp represents ''Bitmap Image File'', which is an image file format.<br />
- .smf<br />
||Incorrect, smf represents ''Standard MIDI Format'', which is used to store MIDI information.<br />
<br />
{ How many information channels can a MIDI link hold?<br />
| type="()" }<br />
- 8<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
+ 16<br />
||Correct, a MIDI link can hold 16 channels of information.<br />
- 32<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
- 64<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
<br />
{If the audio you want to sample is at 44hz, what frequency should you sample at?<br />
|type="{}"}<br />
{ 88 _3 } hz.<br />
<br />
<br />
{What does MIDI stand for?<br />
| type="()" }<br />
- Musical Intelligent Dialogue Interface<br />
||Incorrect<br />
+ Musical Instrument Digital Interface<br />
||Correct<br />
- Muselk Instrument Digital Interface<br />
||Incorrect<br />
- Musical Instrument Detection Interface<br />
||Incorrect<br />
<br />
{If the dots represented the sample rate of the picture below, does it give a good representation of the sample rate ?<br />
[[File:Sample rate.png]]<br />
| type="()" }<br />
-Yes<br />
||Incorrect<br />
+No<br />
||Correct<br />
<br />
<br />
{ A sound is sampled at 3 KHz with a sample resolution of 8 bits. How many bytes will be used for 5 seconds of sound?<br />
| type="()" }<br />
- 120000<br />
|| That is the amount of bits used<br />
- 24000<br />
|| That is only for 1 second, and in bits<br />
+ 15000<br />
|| Correct answer<br />
- 1875 <br />
|| Incorrect!<br />
<br />
|| '''How to calculate'''<br />
|| Number of bits / Number of bits in a byte, 8/8 = 1<br />
|| Samples = sample rate in hertz, 3*1000 = 3000<br />
|| 5 seconds of sound<br />
|| 3000 * 1 * 5 = 15000<br />
<br />
{ A sound is sampled at 6 KHz with a sample resolution of 12 bits. How many bytes will be used for 3 seconds of sound?<br />
| type="()" }<br />
- 216000<br />
|| That is the amount of bits used<br />
+ 27000<br />
|| Correct answer<br />
- 18000<br />
|| You ignored the sample resolution<br />
- 9000<br />
|| That is only for 1 second<br />
<br />
|| '''How to calculate'''<br />
|| Number of bits / Number of bits in a byte, 12/8 = 1.5<br />
|| Samples = sample rate in hertz, 6*1000 = 6000<br />
|| 3 seconds of sound<br />
|| 6000 * 1.5 * 3 = 27000<br />
<br />
{ If an audio is sampled at 72 Hz, what frequency should the original sound have? <br />
| type="{}"}<br />
{ 36 } Hz<br />
<br />
<br />
{ If a sound has a frequency of 27 Hz, what frequency should we sample at?<br />
| type="{}"}<br />
{ 54 } Hz<br />
<br />
<br />
{ Which of the following are advantages of audio streaming?<br />
| type="[]"}<br />
+ It reduces piracy<br />
||Correct<br />
- You can listen to all the audio without interruption<br />
|| If the connection is lost you need to reconnect to listen to the other parts of the file<br />
- You can instantly start listening<br />
|| The audio must buffer first<br />
+ You do not need to download the whole file<br />
||Correct<br />
<br />
{You record 10 seconds of audio, setting the sample rate to 44.1kHz and using 16 bits per sample. Calculate the file size.<br />
| type="{}"}<br />
{ 882 } KB<br />
<br />
<br />
{How is an analogue wave described ? <br />
| type="()"}<br />
- A digital wave that cannot be produced by humans<br />
||Incorrect<br />
- A digital wave that can be produced by humans<br />
||Incorrect<br />
+ A smooth wave that can be produced by humans<br />
||Correct<br />
- A smooth wave that cannot be produced by humans<br />
||Incorrect<br />
<br />
{ How does MIDI create sound files?<br />
| type="()"}<br />
+ Writes a set of instructions using prerecorded and synthesised sounds<br />
||Correct<br />
- Converts analogue to digital sound<br />
||Incorrect<br />
- Writes a set of instructions using only ever prerecorded sounds<br />
||Incorrect<br />
- Writes a set of instructions using only ever synthesised sounds<br />
||Incorrect<br />
<br />
{ MIDI does not create smaller sound file sizes than conventional methods.<br />
| type="()"}<br />
- TRUE<br />
||Incorrect<br />
+ FALSE <br />
||Correct<br />
<br />
{ Which is true of sound synthesis?<br />
| type="[]"}<br />
- Synthesises from an imputed analogue sound wave<br />
+ Produced digitally <br />
+ A digital to analogue converter is required to listen to the synthesised sound<br />
- Sounds created by a computer can be analogue or digital<br />
|| can only be digital must be converted to analogue <br />
<br />
</quiz></div>000032680https://www.trccompsci.online/mediawiki/index.php?title=Sound&diff=7379Sound2019-10-16T09:11:52Z<p>000032680: /* Revision Questions */</p>
<hr />
<div>=Overview=<br />
===Computer Science Tutor===<br />
<youtube>HlOTuCFtuV8</youtube><br />
<br />
https://www.youtube.com/watch?v=HlOTuCFtuV8&list=PL04uZ7242_M6O_6ITD6ncf7EonVHyBeCm&index=9<br />
<br />
===TRC PowerPoint===<br />
[https://studentthomrothac-my.sharepoint.com/:p:/g/personal/wayne_jones_thomroth_ac_uk/Ebzu5zwPN85NnUj6124W7AgBMe8qBBKxLOG0yw3HP20_hg?e=N811yn Sound]<br />
<br />
==Converting Analogue to Digital Sound==<br />
<br />
The following image demonstrates how sound files are created when they are inputted through devices such as a microphone:<br />
<br />
[[File:600px-Analogue_Digital_Conversion.png]]<br />
<br />
further explanation:<br />
<br />
<youtube>https://www.youtube.com/watch?v=VyqGzUbTphs&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4&index=1</youtube><br />
<br />
https://www.youtube.com/watch?v=VyqGzUbTphs&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4&index=1<br />
<br />
==Representing Sound==<br />
<br />
To store sound, a digitizer is needed to convert the analogue sound into digital sound. An analogue to digital converter carries out these conversions. 16 bit ADC is enough for CD quality sound. For High-Res audio, you can get audio files that are at 24 bit.<br />
<br />
[[File:Sound Samples.gif]]<br />
<br />
====Sampling Rate====<br />
<br />
The sampling rate or frequency is the number of samples taken per second. It is measured in hertz (Hz). The higher the sampling rate the more accurate the representation of the sound. But the higher the sampling rate, the bigger the file size will be as there will be more data the is being stored<br />
<br />
[[File:Sound Sampling Rate.jpg|200px]]<br />
<br />
====Sampling Resolution====<br />
<br />
The sampling resolution is the number of bits assigned to each sample. The number of bits assigned allows for a wider range of sounds to be displayed. For example, if only one bit is used it can only be either 1 or 0, giving an option of only two different sounds, where as if 8 bits are used there are a possible 255 different sounds that can be recorded and then replayed. In a way, your PC bleeper speaker is one bit as it only produces one tone when there is a error on your computer and then your actual speakers that you listen to music to will be 8 bit sound as you can play 255 different sounds on it.<br />
<br />
====Additional Video====<br />
<br />
<youtube>https://www.youtube.com/watch?v=v7RwEnirp7I&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=v7RwEnirp7I&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
<br />
====Calculating File Size====<br />
A sound is sampled at 5kHz (5000 Hz) and the sample resolution is 16 bits:<br />
<br />
# There is 5000 samples per second & each sample is 2 byte (16 bits)<br />
# 1 second of sound will be 5000 x 2 = 10,000 Bytes<br />
# 10 seconds of sound will be 5000 x 20 = 100,000 Bytes<br />
<br />
<youtube>https://www.youtube.com/watch?v=al5HsKIRhQw&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=al5HsKIRhQw&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
<br />
====Sampling Process====<br />
<br />
Pulse Amplitude Modulation (PAM) is the process which samples analogue signals and produces electrical pulses of height proportional to the signal's original amplitude.<br />
<br />
Pulse Code Modulation (PCM) is the process of coding sampled analogue signals by recording the height of each sample in binary.<br />
PCM pulses can then be encoded in binary form.<br />
<br />
== Nyquist's Theorem ==<br />
<br />
In 1928 Harry Nyquist found that in order to sample any sound at a similar quality to how it is in real life, you must use a sampling rate at double the frequency of the original sound. The result will be the closest possible to the original sound, because recording at double the frequency allows for all of the changes in the sound such as pitch to be captured digitally at a high quality.<br />
<br />
== MIDI Data ==<br />
<br />
MIDI stands for Musical Instrument Digital Interface.<br />
<br />
MIDI does a completely different approach to other sound recording methods. Instead of recording sound and then storing it in a digital format, It actually writes out a set of instructions which can be used to synthesize the sound that is listened to.<br />
This relies solely on pre-recorded digital samples and synthesized samples of sounds created by different instruments.<br />
<br />
The advantages of using MIDI instead of conventional recording methods is that firstly, it is a fraction of the size of a digital recorded version, it is easily edited or manipulated and notes can be passed to a different instrument and so the attributes of each note can be altered.<br />
<br />
<youtube>https://www.youtube.com/watch?v=AvqP3BhO0d8&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=AvqP3BhO0d8&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
<br />
== Audio Compression ==<br />
<br />
Audio compression is used to lower the storage space that a digital sound file takes up by removing sounds that humans won't be able to pick up listening to it. For example, in a song with guitar and drums, when there is a loud drum hit, the guitar will often be drowned out and could even become completely inaudible, so this data is removed to reduce the size of the audio file so it takes up less storage space, which is useful for devices like phones with a limited storage space. It is also useful for streaming music as it reduces the chance of the music buffering by reducing the amount of data which needs to be sent allowing for smoother more consistent listening.<br />
<br />
== Audio Streaming ==<br />
<br />
Audio streaming is a way in which audio/sound is broadcast to a user. It allows a user to listen to an audio file or watch a video without downloading the whole file, they only download a bit at a time... Which is the buffer.<br />
<br />
Audio Streaming has a delayed start in order to allow it to buffer, it also plays sound from the buffer and has seamless play unless connection to the host is lost. Audio Streaming saves space on the hard drive since the file is no longer required to be downloaded on the device for it be viewed, Which also means piracy is reduced.<br />
<br />
Audio streaming is so widely used and respected because of its usefulness. Before Audio Streaming was around, it could take you quite a while to listen to music/sound since you would have to download the whole file. Whereas Audio Streaming simply gives you the data that you need at that specific time and downloads the next when you need it. It does this simply by holding the data in the buffer.<br />
<br />
== Synthesising Sound ==<br />
<br />
Sound can be synthesised with MIDI (Musical Instrument Digital Interface), which records information about each note - such as duration, pitch, tempo, instrument and volume - and recreates that note when played. When using MIDI it is hard to replicate the proper sound as it would have to be played through note by note and would be a synthetic sound, in some cases it's good like in pop music but in other cases usually not. A MIDI link can hold up to 16 channels of information which can be routed to a seperate device for each channel.<br />
<br />
<br />
=Revision Questions=<br />
<br />
<quiz><br />
{ How many bits is enough for CD quality audio? <br />
| type="()" }<br />
+ 16 bit<br />
||Correct, you only need 16 bits to achieve CD quality audio.<br />
- 24 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
- 32 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
- 64 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
<br />
{ According to Nyquist's Theorem, what should our sampling rate be?<br />
| type="()" }<br />
- Half the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
- The same as the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
+ Double the original rate.<br />
||Correct, sampling at double the rate of the original audio will achieve the closest match.<br />
- Triple the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
<br />
{ Which of the following are examples of audio file formats?<br />
| type="[]" }<br />
+ .mp3<br />
||Correct, mp3 represents ''MPEG-1 or MPEG-2 Audio Layer III'' audio file format.<br />
+ .wav<br />
||Correct, wav represents ''Waveform Audio File Format''.<br />
- .bmp<br />
||Incorrect, bmp represents ''Bitmap Image File'', which is an image file format.<br />
- .smf<br />
||Incorrect, smf represents ''Standard MIDI Format'', which is used to store MIDI information.<br />
<br />
{ How many information channels can a MIDI link hold?<br />
| type="()" }<br />
- 8<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
+ 16<br />
||Correct, a MIDI link can hold 16 channels of information.<br />
- 32<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
- 64<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
<br />
{If the audio you want to sample is at 44hz, what frequency should you sample at?<br />
|type="{}"}<br />
{ 88 _3 } hz.<br />
<br />
<br />
{What does MIDI stand for?<br />
| type="()" }<br />
- Musical Intelligent Dialogue Interface<br />
||Incorrect<br />
+ Musical Instrument Digital Interface<br />
||Correct<br />
- Muselk Instrument Digital Interface<br />
||Incorrect<br />
- Musical Instrument Detection Interface<br />
||Incorrect<br />
<br />
{If the dots represented the sample rate of the picture below, does it give a good representation of the sample rate ?<br />
[[File:Sample rate.png]]<br />
| type="()" }<br />
-Yes<br />
||Incorrect<br />
+No<br />
||Correct<br />
<br />
<br />
{ A sound is sampled at 3 KHz with a sample resolution of 8 bits. How many bytes will be used for 5 seconds of sound?<br />
| type="()" }<br />
- 120000<br />
|| That is the amount of bits used<br />
- 24000<br />
|| That is only for 1 second, and in bits<br />
+ 15000<br />
|| Correct answer<br />
- 1875 <br />
|| Incorrect!<br />
<br />
|| '''How to calculate'''<br />
|| Number of bits / Number of bits in a byte, 8/8 = 1<br />
|| Samples = sample rate in hertz, 3*1000 = 3000<br />
|| 5 seconds of sound<br />
|| 3000 * 1 * 5 = 15000<br />
<br />
{ A sound is sampled at 6 KHz with a sample resolution of 12 bits. How many bytes will be used for 3 seconds of sound?<br />
| type="()" }<br />
- 216000<br />
|| That is the amount of bits used<br />
+ 27000<br />
|| Correct answer<br />
- 18000<br />
|| You ignored the sample resolution<br />
- 9000<br />
|| That is only for 1 second<br />
<br />
|| '''How to calculate'''<br />
|| Number of bits / Number of bits in a byte, 12/8 = 1.5<br />
|| Samples = sample rate in hertz, 6*1000 = 6000<br />
|| 3 seconds of sound<br />
|| 6000 * 1.5 * 3 = 27000<br />
<br />
{ If an audio is sampled at 72 Hz, what frequency should the original sound have? <br />
| type="{}"}<br />
{ 36 } Hz<br />
<br />
<br />
{ If a sound has a frequency of 27 Hz, what frequency should we sample at?<br />
| type="{}"}<br />
{ 54 } Hz<br />
<br />
<br />
{ Which of the following are advantages of audio streaming?<br />
| type="[]"}<br />
+ It reduces piracy<br />
||Correct<br />
- You can listen to all the audio without interruption<br />
|| If the connection is lost you need to reconnect to listen to the other parts of the file<br />
- You can instantly start listening<br />
|| The audio must buffer first<br />
+ You do not need to download the whole file<br />
||Correct<br />
<br />
{You record 10 seconds of audio, setting the sample rate to 44.1kHz and using 16 bits per sample. Calculate the file size.<br />
| type="{}"}<br />
{ 882 } KB<br />
<br />
<br />
{How is an analogue wave described ? <br />
| type="()"}<br />
- A digital wave that cannot be produced by humans<br />
||Incorrect<br />
- A digital wave that can be produced by humans<br />
||Incorrect<br />
+ A smooth wave that can be produced by humans<br />
||Correct<br />
- A smooth wave that cannot be produced by humans<br />
||Incorrect<br />
<br />
{ How does MIDI create sound files?<br />
| type="()"}<br />
+ Writes a set of instructions using prerecorded and synthesised sounds<br />
||Correct<br />
- Converts analogue to digital sound<br />
||Incorrect<br />
- Writes a set of instructions using only ever prerecorded sounds<br />
||Incorrect<br />
- Writes a set of instructions using only ever synthesised sounds<br />
||Incorrect<br />
<br />
{ MIDI does not create smaller sound file sizes than conventional methods.<br />
| type="()"}<br />
- TRUE<br />
||Incorrect<br />
+ FALSE <br />
||Correct<br />
<br />
{ Which is true of sound synthesis?<br />
| type="()"}<br />
- Synthesises from an imputed analogue sound wave<br />
+ Produced digitally <br />
+ A digital to analogue converter is required to listen to the synthesised sound<br />
- Sounds created by a computer can be analogue or digital<br />
|| can only be digital must be converted to analogue <br />
<br />
</quiz></div>000032680https://www.trccompsci.online/mediawiki/index.php?title=Sound&diff=7373Sound2019-10-16T09:07:44Z<p>000032680: /* Revision Questions */</p>
<hr />
<div>=Overview=<br />
===Computer Science Tutor===<br />
<youtube>HlOTuCFtuV8</youtube><br />
<br />
https://www.youtube.com/watch?v=HlOTuCFtuV8&list=PL04uZ7242_M6O_6ITD6ncf7EonVHyBeCm&index=9<br />
<br />
===TRC PowerPoint===<br />
[https://studentthomrothac-my.sharepoint.com/:p:/g/personal/wayne_jones_thomroth_ac_uk/Ebzu5zwPN85NnUj6124W7AgBMe8qBBKxLOG0yw3HP20_hg?e=N811yn Sound]<br />
<br />
==Converting Analogue to Digital Sound==<br />
<br />
The following image demonstrates how sound files are created when they are inputted through devices such as a microphone:<br />
<br />
[[File:600px-Analogue_Digital_Conversion.png]]<br />
<br />
further explanation:<br />
<br />
<youtube>https://www.youtube.com/watch?v=VyqGzUbTphs&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4&index=1</youtube><br />
<br />
https://www.youtube.com/watch?v=VyqGzUbTphs&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4&index=1<br />
<br />
==Representing Sound==<br />
<br />
To store sound, a digitizer is needed to convert the analogue sound into digital sound. An analogue to digital converter carries out these conversions. 16 bit ADC is enough for CD quality sound. For High-Res audio, you can get audio files that are at 24 bit.<br />
<br />
[[File:Sound Samples.gif]]<br />
<br />
====Sampling Rate====<br />
<br />
The sampling rate or frequency is the number of samples taken per second. It is measured in hertz (Hz). The higher the sampling rate the more accurate the representation of the sound. But the higher the sampling rate, the bigger the file size will be as there will be more data the is being stored<br />
<br />
[[File:Sound Sampling Rate.jpg|200px]]<br />
<br />
====Sampling Resolution====<br />
<br />
The sampling resolution is the number of bits assigned to each sample. The number of bits assigned allows for a wider range of sounds to be displayed. For example, if only one bit is used it can only be either 1 or 0, giving an option of only two different sounds, where as if 8 bits are used there are a possible 255 different sounds that can be recorded and then replayed. In a way, your PC bleeper speaker is one bit as it only produces one tone when there is a error on your computer and then your actual speakers that you listen to music to will be 8 bit sound as you can play 255 different sounds on it.<br />
<br />
====Additional Video====<br />
<br />
<youtube>https://www.youtube.com/watch?v=v7RwEnirp7I&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=v7RwEnirp7I&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
<br />
====Calculating File Size====<br />
A sound is sampled at 5kHz (5000 Hz) and the sample resolution is 16 bits:<br />
<br />
# There is 5000 samples per second & each sample is 2 byte (16 bits)<br />
# 1 second of sound will be 5000 x 2 = 10,000 Bytes<br />
# 10 seconds of sound will be 5000 x 20 = 100,000 Bytes<br />
<br />
<youtube>https://www.youtube.com/watch?v=al5HsKIRhQw&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=al5HsKIRhQw&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
<br />
====Sampling Process====<br />
<br />
Pulse Amplitude Modulation (PAM) is the process which samples analogue signals and produces electrical pulses of height proportional to the signal's original amplitude.<br />
<br />
Pulse Code Modulation (PCM) is the process of coding sampled analogue signals by recording the height of each sample in binary.<br />
PCM pulses can then be encoded in binary form.<br />
<br />
== Nyquist's Theorem ==<br />
<br />
In 1928 Harry Nyquist found that in order to sample any sound at a similar quality to how it is in real life, you must use a sampling rate at double the frequency of the original sound. The result will be the closest possible to the original sound, because recording at double the frequency allows for all of the changes in the sound such as pitch to be captured digitally at a high quality.<br />
<br />
== MIDI Data ==<br />
<br />
MIDI stands for Musical Instrument Digital Interface.<br />
<br />
MIDI does a completely different approach to other sound recording methods. Instead of recording sound and then storing it in a digital format, It actually writes out a set of instructions which can be used to synthesize the sound that is listened to.<br />
This relies solely on pre-recorded digital samples and synthesized samples of sounds created by different instruments.<br />
<br />
The advantages of using MIDI instead of conventional recording methods is that firstly, it is a fraction of the size of a digital recorded version, it is easily edited or manipulated and notes can be passed to a different instrument and so the attributes of each note can be altered.<br />
<br />
<youtube>https://www.youtube.com/watch?v=AvqP3BhO0d8&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=AvqP3BhO0d8&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
<br />
== Audio Compression ==<br />
<br />
Audio compression is used to lower the storage space that a digital sound file takes up by removing sounds that humans won't be able to pick up listening to it. For example, in a song with guitar and drums, when there is a loud drum hit, the guitar will often be drowned out and could even become completely inaudible, so this data is removed to reduce the size of the audio file so it takes up less storage space, which is useful for devices like phones with a limited storage space. It is also useful for streaming music as it reduces the chance of the music buffering by reducing the amount of data which needs to be sent allowing for smoother more consistent listening.<br />
<br />
== Audio Streaming ==<br />
<br />
Audio streaming is a way in which audio/sound is broadcast to a user. It allows a user to listen to an audio file or watch a video without downloading the whole file, they only download a bit at a time... Which is the buffer.<br />
<br />
Audio Streaming has a delayed start in order to allow it to buffer, it also plays sound from the buffer and has seamless play unless connection to the host is lost. Audio Streaming saves space on the hard drive since the file is no longer required to be downloaded on the device for it be viewed, Which also means piracy is reduced.<br />
<br />
Audio streaming is so widely used and respected because of its usefulness. Before Audio Streaming was around, it could take you quite a while to listen to music/sound since you would have to download the whole file. Whereas Audio Streaming simply gives you the data that you need at that specific time and downloads the next when you need it. It does this simply by holding the data in the buffer.<br />
<br />
== Synthesising Sound ==<br />
<br />
Sound can be synthesised with MIDI (Musical Instrument Digital Interface), which records information about each note - such as duration, pitch, tempo, instrument and volume - and recreates that note when played. When using MIDI it is hard to replicate the proper sound as it would have to be played through note by note and would be a synthetic sound, in some cases it's good like in pop music but in other cases usually not. A MIDI link can hold up to 16 channels of information which can be routed to a seperate device for each channel.<br />
<br />
<br />
=Revision Questions=<br />
<br />
<quiz display=simple><br />
{ How many bits is enough for CD quality audio? <br />
| type="()" }<br />
+ 16 bit<br />
||Correct, you only need 16 bits to achieve CD quality audio.<br />
- 24 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
- 32 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
- 64 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
<br />
{ According to Nyquist's Theorem, what should our sampling rate be?<br />
| type="()" }<br />
- Half the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
- The same as the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
+ Double the original rate.<br />
||Correct, sampling at double the rate of the original audio will achieve the closest match.<br />
- Triple the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
<br />
{ Which of the following are examples of audio file formats?<br />
| type="[]" }<br />
+ .mp3<br />
||Correct, mp3 represents ''MPEG-1 or MPEG-2 Audio Layer III'' audio file format.<br />
+ .wav<br />
||Correct, wav represents ''Waveform Audio File Format''.<br />
- .bmp<br />
||Incorrect, bmp represents ''Bitmap Image File'', which is an image file format.<br />
- .smf<br />
||Incorrect, smf represents ''Standard MIDI Format'', which is used to store MIDI information.<br />
<br />
{ How many information channels can a MIDI link hold?<br />
| type="()" }<br />
- 8<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
+ 16<br />
||Correct, a MIDI link can hold 16 channels of information.<br />
- 32<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
- 64<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
<br />
{If the audio you want to sample is at 44hz, what frequency should you sample at?<br />
|type="{}"}<br />
{ 88 _3 } hz.<br />
<br />
<br />
{What does MIDI stand for?<br />
| type="()" }<br />
- Musical Intelligent Dialogue Interface<br />
||Incorrect<br />
+ Musical Instrument Digital Interface<br />
||Correct<br />
- Muselk Instrument Digital Interface<br />
||Incorrect<br />
- Musical Instrument Detection Interface<br />
||Incorrect<br />
<br />
{If the dots represented the sample rate of the picture below, does it give a good representation of the sample rate ?<br />
[[File:Sample rate.png]]<br />
| type="()" }<br />
-Yes<br />
||Incorrect<br />
+No<br />
||Correct<br />
<br />
<br />
{ A sound is sampled at 3 KHz with a sample resolution of 8 bits. How many bytes will be used for 5 seconds of sound?<br />
| type="()" }<br />
- 120000<br />
|| That is the amount of bits used<br />
- 24000<br />
|| That is only for 1 second, and in bits<br />
+ 15000<br />
|| Correct answer<br />
- 1875 <br />
|| Incorrect!<br />
<br />
|| '''How to calculate'''<br />
|| Number of bits / Number of bits in a byte, 8/8 = 1<br />
|| Samples = sample rate in hertz, 3*1000 = 3000<br />
|| 5 seconds of sound<br />
|| 3000 * 1 * 5 = 15000<br />
<br />
{ A sound is sampled at 6 KHz with a sample resolution of 12 bits. How many bytes will be used for 3 seconds of sound?<br />
| type="()" }<br />
- 216000<br />
|| That is the amount of bits used<br />
+ 27000<br />
|| Correct answer<br />
- 18000<br />
|| You ignored the sample resolution<br />
- 9000<br />
|| That is only for 1 second<br />
<br />
|| '''How to calculate'''<br />
|| Number of bits / Number of bits in a byte, 12/8 = 1.5<br />
|| Samples = sample rate in hertz, 6*1000 = 6000<br />
|| 3 seconds of sound<br />
|| 6000 * 1.5 * 3 = 27000<br />
<br />
{ If an audio is sampled at 72 Hz, what frequency should the original sound have? <br />
| type="{}"}<br />
{ 36 } Hz<br />
<br />
<br />
{ If a sound has a frequency of 27 Hz, what frequency should we sample at?<br />
| type="{}"}<br />
{ 54 } Hz<br />
<br />
<br />
{ Which of the following are advantages of audio streaming?<br />
| type="[]"}<br />
+ It reduces piracy<br />
||Correct<br />
- You can listen to all the audio without interruption<br />
|| If the connection is lost you need to reconnect to listen to the other parts of the file<br />
- You can instantly start listening<br />
|| The audio must buffer first<br />
+ You do not need to download the whole file<br />
||Correct<br />
<br />
{You record 10 seconds of audio, setting the sample rate to 44.1kHz and using 16 bits per sample. Calculate the file size.<br />
| type="{}"}<br />
{ 882 } KB<br />
<br />
<br />
{How is an analogue wave described ? <br />
| type="()"}<br />
- A digital wave that cannot be produced by humans<br />
||Incorrect<br />
- A digital wave that can be produced by humans<br />
||Incorrect<br />
+ A smooth wave that can be produced by humans<br />
||Correct<br />
- A smooth wave that cannot be produced by humans<br />
||Incorrect<br />
<br />
{ How does MIDI create sound files?<br />
| type="()"}<br />
+ Writes a set of instructions using prerecorded and synthesised sounds<br />
||Correct<br />
- Converts analogue to digital sound<br />
||Incorrect<br />
- Writes a set of instructions using only ever prerecorded sounds<br />
||Incorrect<br />
- Writes a set of instructions using only ever synthesised sounds<br />
||Incorrect<br />
<br />
{ MIDI does not create smaller sound file sizes than conventional methods.<br />
| type="()"}<br />
- TRUE<br />
||Incorrect<br />
+ FALSE <br />
||Correct<br />
<br />
</quiz></div>000032680https://www.trccompsci.online/mediawiki/index.php?title=Sound&diff=7366Sound2019-10-16T09:04:30Z<p>000032680: </p>
<hr />
<div>=Overview=<br />
===Computer Science Tutor===<br />
<youtube>HlOTuCFtuV8</youtube><br />
<br />
https://www.youtube.com/watch?v=HlOTuCFtuV8&list=PL04uZ7242_M6O_6ITD6ncf7EonVHyBeCm&index=9<br />
<br />
===TRC PowerPoint===<br />
[https://studentthomrothac-my.sharepoint.com/:p:/g/personal/wayne_jones_thomroth_ac_uk/Ebzu5zwPN85NnUj6124W7AgBMe8qBBKxLOG0yw3HP20_hg?e=N811yn Sound]<br />
<br />
==Converting Analogue to Digital Sound==<br />
<br />
The following image demonstrates how sound files are created when they are inputted through devices such as a microphone:<br />
<br />
[[File:600px-Analogue_Digital_Conversion.png]]<br />
<br />
further explanation:<br />
<br />
<youtube>https://www.youtube.com/watch?v=VyqGzUbTphs&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4&index=1</youtube><br />
<br />
https://www.youtube.com/watch?v=VyqGzUbTphs&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4&index=1<br />
<br />
==Representing Sound==<br />
<br />
To store sound, a digitizer is needed to convert the analogue sound into digital sound. An analogue to digital converter carries out these conversions. 16 bit ADC is enough for CD quality sound. For High-Res audio, you can get audio files that are at 24 bit.<br />
<br />
[[File:Sound Samples.gif]]<br />
<br />
====Sampling Rate====<br />
<br />
The sampling rate or frequency is the number of samples taken per second. It is measured in hertz (Hz). The higher the sampling rate the more accurate the representation of the sound. But the higher the sampling rate, the bigger the file size will be as there will be more data the is being stored<br />
<br />
[[File:Sound Sampling Rate.jpg|200px]]<br />
<br />
====Sampling Resolution====<br />
<br />
The sampling resolution is the number of bits assigned to each sample. The number of bits assigned allows for a wider range of sounds to be displayed. For example, if only one bit is used it can only be either 1 or 0, giving an option of only two different sounds, where as if 8 bits are used there are a possible 255 different sounds that can be recorded and then replayed. In a way, your PC bleeper speaker is one bit as it only produces one tone when there is a error on your computer and then your actual speakers that you listen to music to will be 8 bit sound as you can play 255 different sounds on it.<br />
<br />
====Additional Video====<br />
<br />
<youtube>https://www.youtube.com/watch?v=v7RwEnirp7I&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=v7RwEnirp7I&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
<br />
====Calculating File Size====<br />
A sound is sampled at 5kHz (5000 Hz) and the sample resolution is 16 bits:<br />
<br />
# There is 5000 samples per second & each sample is 2 byte (16 bits)<br />
# 1 second of sound will be 5000 x 2 = 10,000 Bytes<br />
# 10 seconds of sound will be 5000 x 20 = 100,000 Bytes<br />
<br />
<youtube>https://www.youtube.com/watch?v=al5HsKIRhQw&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=al5HsKIRhQw&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
<br />
====Sampling Process====<br />
<br />
Pulse Amplitude Modulation (PAM) is the process which samples analogue signals and produces electrical pulses of height proportional to the signal's original amplitude.<br />
<br />
Pulse Code Modulation (PCM) is the process of coding sampled analogue signals by recording the height of each sample in binary.<br />
PCM pulses can then be encoded in binary form.<br />
<br />
== Nyquist's Theorem ==<br />
<br />
In 1928 Harry Nyquist found that in order to sample any sound at a similar quality to how it is in real life, you must use a sampling rate at double the frequency of the original sound. The result will be the closest possible to the original sound, because recording at double the frequency allows for all of the changes in the sound such as pitch to be captured digitally at a high quality.<br />
<br />
== MIDI Data ==<br />
<br />
MIDI stands for Musical Instrument Digital Interface.<br />
<br />
MIDI does a completely different approach to other sound recording methods. Instead of recording sound and then storing it in a digital format, It actually writes out a set of instructions which can be used to synthesize the sound that is listened to.<br />
This relies solely on pre-recorded digital samples and synthesized samples of sounds created by different instruments.<br />
<br />
The advantages of using MIDI instead of conventional recording methods is that firstly, it is a fraction of the size of a digital recorded version, it is easily edited or manipulated and notes can be passed to a different instrument and so the attributes of each note can be altered.<br />
<br />
<youtube>https://www.youtube.com/watch?v=AvqP3BhO0d8&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=AvqP3BhO0d8&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
<br />
== Audio Compression ==<br />
<br />
Audio compression is used to lower the storage space that a digital sound file takes up by removing sounds that humans won't be able to pick up listening to it. For example, in a song with guitar and drums, when there is a loud drum hit, the guitar will often be drowned out and could even become completely inaudible, so this data is removed to reduce the size of the audio file so it takes up less storage space, which is useful for devices like phones with a limited storage space. It is also useful for streaming music as it reduces the chance of the music buffering by reducing the amount of data which needs to be sent allowing for smoother more consistent listening.<br />
<br />
== Audio Streaming ==<br />
<br />
Audio streaming is a way in which audio/sound is broadcast to a user. It allows a user to listen to an audio file or watch a video without downloading the whole file, they only download a bit at a time... Which is the buffer.<br />
<br />
Audio Streaming has a delayed start in order to allow it to buffer, it also plays sound from the buffer and has seamless play unless connection to the host is lost. Audio Streaming saves space on the hard drive since the file is no longer required to be downloaded on the device for it be viewed, Which also means piracy is reduced.<br />
<br />
Audio streaming is so widely used and respected because of its usefulness. Before Audio Streaming was around, it could take you quite a while to listen to music/sound since you would have to download the whole file. Whereas Audio Streaming simply gives you the data that you need at that specific time and downloads the next when you need it. It does this simply by holding the data in the buffer.<br />
<br />
== Synthesising Sound ==<br />
<br />
Sound can be synthesised with MIDI (Musical Instrument Digital Interface), which records information about each note - such as duration, pitch, tempo, instrument and volume - and recreates that note when played. When using MIDI it is hard to replicate the proper sound as it would have to be played through note by note and would be a synthetic sound, in some cases it's good like in pop music but in other cases usually not. A MIDI link can hold up to 16 channels of information which can be routed to a seperate device for each channel.<br />
<br />
<br />
=Revision Questions=<br />
<br />
<quiz display=simple><br />
{ How many bits is enough for CD quality audio? <br />
| type="()" }<br />
+ 16 bit<br />
||Correct, you only need 16 bits to achieve CD quality audio.<br />
- 24 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
- 32 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
- 64 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
<br />
{ According to Nyquist's Theorem, what should our sampling rate be?<br />
| type="()" }<br />
- Half the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
- The same as the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
+ Double the original rate.<br />
||Correct, sampling at double the rate of the original audio will achieve the closest match.<br />
- Triple the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
<br />
{ Which of the following are examples of audio file formats?<br />
| type="[]" }<br />
+ .mp3<br />
||Correct, mp3 represents ''MPEG-1 or MPEG-2 Audio Layer III'' audio file format.<br />
+ .wav<br />
||Correct, wav represents ''Waveform Audio File Format''.<br />
- .bmp<br />
||Incorrect, bmp represents ''Bitmap Image File'', which is an image file format.<br />
- .smf<br />
||Incorrect, smf represents ''Standard MIDI Format'', which is used to store MIDI information.<br />
<br />
{ How many information channels can a MIDI link hold?<br />
| type="()" }<br />
- 8<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
+ 16<br />
||Correct, a MIDI link can hold 16 channels of information.<br />
- 32<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
- 64<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
<br />
{If the audio you want to sample is at 44hz, what frequency should you sample at?<br />
|type="{}"}<br />
{ 88 _3 } hz.<br />
||Correct<br />
<br />
{What does MIDI stand for?<br />
| type="()" }<br />
- Musical Intelligent Dialogue Interface<br />
||Incorrect<br />
+ Musical Instrument Digital Interface<br />
||Correct<br />
- Muselk Instrument Digital Interface<br />
||Incorrect<br />
- Musical Instrument Detection Interface<br />
||Incorrect<br />
<br />
{If the dots represented the sample rate of the picture below, does it give a good representation of the sample rate ?<br />
[[File:Sample rate.png]]<br />
| type="()" }<br />
-Yes<br />
||Incorrect<br />
+No<br />
||Correct<br />
<br />
<br />
{ A sound is sampled at 3 KHz with a sample resolution of 8 bits. How many bytes will be used for 5 seconds of sound?<br />
| type="()" }<br />
- 120000<br />
|| That is the amount of bits used<br />
- 24000<br />
|| That is only for 1 second, and in bits<br />
+ 15000<br />
|| Correct answer<br />
- 1875 <br />
|| Incorrect!<br />
<br />
|| '''How to calculate'''<br />
|| Number of bits / Number of bits in a byte, 8/8 = 1<br />
|| Samples = sample rate in hertz, 3*1000 = 3000<br />
|| 5 seconds of sound<br />
|| 3000 * 1 * 5 = 15000<br />
<br />
{ A sound is sampled at 6 KHz with a sample resolution of 12 bits. How many bytes will be used for 3 seconds of sound?<br />
| type="()" }<br />
- 216000<br />
|| That is the amount of bits used<br />
+ 27000<br />
|| Correct answer<br />
- 18000<br />
|| You ignored the sample resolution<br />
- 9000<br />
|| That is only for 1 second<br />
<br />
|| '''How to calculate'''<br />
|| Number of bits / Number of bits in a byte, 12/8 = 1.5<br />
|| Samples = sample rate in hertz, 6*1000 = 6000<br />
|| 3 seconds of sound<br />
|| 6000 * 1.5 * 3 = 27000<br />
<br />
{ If an audio is sampled at 72 Hz, what frequency should the original sound have? <br />
| type="{}"}<br />
{ 36 } Hz<br />
||Correct<br />
<br />
{ If a sound has a frequency of 27 Hz, what frequency should we sample at?<br />
| type="{}"}<br />
{ 54 } Hz<br />
||Correct<br />
<br />
{ Which of the following are advantages of audio streaming?<br />
| type="[]"}<br />
+ It reduces piracy<br />
||Correct<br />
- You can listen to all the audio without interruption<br />
|| If the connection is lost you need to reconnect to listen to the other parts of the file<br />
- You can instantly start listening<br />
|| The audio must buffer first<br />
+ You do not need to download the whole file<br />
||Correct<br />
<br />
{You record 10 seconds of audio, setting the sample rate to 44.1kHz and using 16 bits per sample. Calculate the file size.<br />
| type="{}"}<br />
{ 882 } KB<br />
||Correct<br />
<br />
{How is an analogue wave described ? <br />
| type="()"}<br />
- A digital wave that cannot be produced by humans<br />
||Incorrect<br />
- A digital wave that can be produced by humans<br />
||Incorrect<br />
+ A smooth wave that can be produced by humans<br />
||Correct<br />
- A smooth wave that cannot be produced by humans<br />
||Incorrect<br />
<br />
{ How does MIDI create sound files?<br />
| type="()"}<br />
+ Writes a set of instructions using prerecorded and synthesised sounds<br />
||Correct<br />
- Converts analogue to digital sound<br />
||Incorrect<br />
- Writes a set of instructions using only ever prerecorded sounds<br />
||Incorrect<br />
- Writes a set of instructions using only ever synthesised sounds<br />
||Incorrect<br />
<br />
{ MIDI does not create smaller sound file sizes than conventional methods.<br />
| type="()"}<br />
- TRUE<br />
||Incorrect<br />
+ FALSE <br />
||Correct<br />
<br />
</quiz></div>000032680https://www.trccompsci.online/mediawiki/index.php?title=Sound&diff=7354Sound2019-10-16T08:54:37Z<p>000032680: /* Revision Questions */</p>
<hr />
<div>=Overview=<br />
===Computer Science Tutor===<br />
<youtube>HlOTuCFtuV8</youtube><br />
<br />
https://www.youtube.com/watch?v=HlOTuCFtuV8&list=PL04uZ7242_M6O_6ITD6ncf7EonVHyBeCm&index=9<br />
<br />
===TRC PowerPoint===<br />
[https://studentthomrothac-my.sharepoint.com/:p:/g/personal/wayne_jones_thomroth_ac_uk/Ebzu5zwPN85NnUj6124W7AgBMe8qBBKxLOG0yw3HP20_hg?e=N811yn Sound]<br />
<br />
==Converting Analogue to Digital Sound==<br />
<br />
The following image demonstrates how sound files are created when they are inputted through devices such as a microphone:<br />
<br />
[[File:600px-Analogue_Digital_Conversion.png]]<br />
<br />
further explanation:<br />
<br />
<youtube>https://www.youtube.com/watch?v=VyqGzUbTphs&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4&index=1</youtube><br />
<br />
https://www.youtube.com/watch?v=VyqGzUbTphs&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4&index=1<br />
<br />
==Representing Sound==<br />
<br />
To store sound, a digitizer is needed to convert the analogue sound into digital sound. An analogue to digital converter carries out these conversions. 16 bit ADC is enough for CD quality sound. For High-Res audio, you can get audio files that are at 24 bit.<br />
<br />
[[File:Sound Samples.gif]]<br />
<br />
====Sampling Rate====<br />
<br />
The sampling rate or frequency is the number of samples taken per second. It is measured in hertz (Hz). The higher the sampling rate the more accurate the representation of the sound. But the higher the sampling rate, the bigger the file size will be as there will be more data the is being stored<br />
<br />
[[File:Sound SamplingRate.jpg|200px]]<br />
<br />
====Sampling Resolution====<br />
<br />
The sampling resolution is the number of bits assigned to each sample. The number of bits assigned allows for a wider range of sounds to be displayed. For example, if only one bit is used it can only be either 1 or 0, giving an option of only two different sounds, where as if 8 bits are used there are a possible 255 different sounds that can be recorded and then replayed. In a way, your PC bleeper speaker is one bit as it only produces one tone when there is a error on your computer and then your actual speakers that you listen to music to will be 8 bit sound as you can play 255 different sounds on it.<br />
<br />
====Additional Video====<br />
<br />
<youtube>https://www.youtube.com/watch?v=v7RwEnirp7I&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=v7RwEnirp7I&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
<br />
====Calculating File Size====<br />
A sound is sampled at 5kHz (5000Hz) and the sample resolution is 16 bits:<br />
<br />
# There is 5000 samples per second & each sample is 2 byte (16 bits)<br />
# 1 second of sound will be 5000 x 2 = 10,000 Bytes<br />
# 10 seconds of sound will be 5000 x 20 = 100,000 Bytes<br />
<br />
<youtube>https://www.youtube.com/watch?v=al5HsKIRhQw&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=al5HsKIRhQw&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
<br />
====Sampling Process====<br />
<br />
Pulse Amplitude Modulation (PAM) is the process which samples analogue signals and produces electrical pulses of height proportional to the signal's original amplitude.<br />
<br />
Pulse Code Modulation (PCM) is the process of coding sampled analogue signals by recording the height of each sample in binary.<br />
PCM pulses can then be encoded in binary form.<br />
<br />
== Nyquist's Theorem ==<br />
<br />
In 1928 Harry Nyquist found that in order to sample any sound at a similar quality to how it is in real life, you must use a sampling rate at double the frequency of the original sound. The result will be the closest possible to the original sound, because recording at double the frequency allows for all of the changes in the sound such as pitch to be captured digitally at a high quality.<br />
<br />
== MIDI Data ==<br />
<br />
MIDI stands for Musical Instrument Digital Interface.<br />
<br />
MIDI does a completely different approach to other sound recording methods. Instead of recording sound and then storing it in a digital format, It actually writes out a set of instructions which can be used to synthesize the sound that is listened to.<br />
This relies solely on pre-recorded digital samples and synthesized samples of sounds created by different instruments.<br />
<br />
The advantages of using MIDI instead of conventional recording methods is that firstly, it is a fraction of the size of a digital recorded version, it is easily edited or manipulated and notes can be passed to a different instrument and so the attributes of each note can be altered.<br />
<br />
<youtube>https://www.youtube.com/watch?v=AvqP3BhO0d8&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=AvqP3BhO0d8&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
<br />
== Audio Compression ==<br />
<br />
Audio compression is used to lower the storage space that a digital sound file takes up by removing sounds that humans won't be able to pick up listening to it. For example, in a song with guitar and drums, when there is a loud drum hit, the guitar will often be drowned out and could even become completely inaudible, so this data is removed to reduce the size of the audio file so it takes up less storage space, which is useful for devices like phones with a limited storage space. It is also useful for streaming music as it reduces the chance of the music buffering by reducing the amount of data which needs to be sent allowing for smoother more consistent listening.<br />
<br />
== Audio Streaming ==<br />
<br />
Audio streaming is a way in which audio/sound is broadcast to a user. It allows a user to listen to an audio file or watch a video without downloading the whole file, they only download a bit at a time... Which is the buffer.<br />
<br />
Audio Streaming has a delayed start in order to allow it to buffer, it also plays sound from the buffer and has seamless play unless connection to the host is lost. Audio Streaming saves space on the hard drive since the file is no longer required to be downloaded on the device for it be viewed, Which also means piracy is reduced.<br />
<br />
Audio streaming is so widely used and respected because of its usefulness. Before Audio Streaming was around, it could take you quite a while to listen to music/sound since you would have to download the whole file. Whereas Audio Streaming simply gives you the data that you need at that specific time and downloads the next when you need it. It does this simply by holding the data in the buffer.<br />
<br />
== Synthesising Sound ==<br />
<br />
Sound can be synthesised with MIDI (Musical Instrument Digital Interface), which records information about each note - such as duration, pitch, tempo, instrument and volume - and recreates that note when played. When using MIDI it is hard to replecate the proper soud as it would have to be played through note by note and would be a synthetic sound, in some cases it's good like in pop music but in other cases usually not. A MIDI link can hold up to 16 channels of information which can be routed to a seperate device for each channel.<br />
<br />
<br />
=Revision Questions=<br />
'''try to add more questions on:<br />
*file size calculations<br />
*ADC to DAC<br />
*Synthesising Sound<br />
*more detailed midi questions<br />
<br />
'''Also '||' is the feedback for an answer, and could be greatly improved'''<br />
<br />
<quiz display=simple><br />
{ How many bits is enough for CD quality audio? <br />
| type="()" }<br />
+ 16 bit<br />
||Correct, you only need 16 bits to achieve CD quality audio.<br />
- 24 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
- 32 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
- 64 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
<br />
{ According to Nyquist's Theorem, what should our sampling rate be?<br />
| type="()" }<br />
- Half the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
- The same as the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
+ Double the original rate.<br />
||Correct, sampling at double the rate of the original audio will achieve the closest match.<br />
- Triple the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
<br />
{ Which of the following are examples of audio file formats?<br />
| type="[]" }<br />
+ .mp3<br />
||Correct, mp3 represents ''MPEG-1 or MPEG-2 Audio Layer III'' audio file format.<br />
+ .wav<br />
||Correct, wav represents ''Waveform Audio File Format''.<br />
- .bmp<br />
||Incorrect, bmp represents ''Bitmap Image File'', which is an image file format.<br />
- .smf<br />
||Incorrect, smf represents ''Standard MIDI Format'', which is used to store MIDI information.<br />
<br />
{ How many information channels can a MIDI link hold?<br />
| type="()" }<br />
- 8<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
+ 16<br />
||Correct, a MIDI link can hold 16 channels of information.<br />
- 32<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
- 64<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
<br />
{If the audio you want to sample is at 44hz, what frequency should you sample at?<br />
|type="{}"}<br />
{ 88 _3 } hz.<br />
<br />
{What does MIDI stand for?<br />
| type="()" }<br />
- Musical Intelligent Dialogue Interface<br />
+ Musical Instrument Digital Interface<br />
- Muselk Instrument Digital Interface<br />
|| Muselk is an overwatch youtuber subscribe at https://www.youtube.com/channel/UCd534c_ehOvrLVL2v7Nl61w<br />
- Musical Instrument Detection Interface<br />
<br />
{If the dots represented the sample rate of the picture below, does it give a good representation of the sample rate ?<br />
[[File:Sample rate.png]]<br />
| type="()" }<br />
-Yes<br />
|| incorrect<br />
+No<br />
||Correct<br />
<br />
<br />
{ A sound is sampled at 3 KHz with a sample resolution of 8 bits. How many bytes will be used for 5 seconds of sound?<br />
| type="()" }<br />
- 120000<br />
|| That is the amount of bits used<br />
- 24000<br />
|| That is only for 1 second, and in bits<br />
+ 15000<br />
|| Correct answer<br />
- 1875 <br />
|| Incorrect!<br />
<br />
|| '''How to calculate'''<br />
|| Number of bits / Number of bits in a byte, 8/8 = 1<br />
|| Samples = sample rate in hertz, 3*1000 = 3000<br />
|| 5 seconds of sound<br />
|| 3000 * 1 * 5 = 15000<br />
<br />
{ A sound is sampled at 6KHz with a sample resolution of 12 bits. How many bytes will be used for 3 seconds of sound?<br />
| type="()" }<br />
- 216000<br />
|| That is the amount of bits used<br />
+ 27000<br />
|| Correct answer<br />
- 18000<br />
|| You ignored the sample resolution<br />
- 9000<br />
|| That is only for 1 second<br />
<br />
|| '''How to calculate'''<br />
|| Number of bits / Number of bits in a byte, 12/8 = 1.5<br />
|| Samples = sample rate in hertz, 6*1000 = 6000<br />
|| 3 seconds of sound<br />
|| 6000 * 1.5 * 3 = 27000<br />
<br />
{ If an audio is sampled at 72 Hz, what frequency should the original sound have? <br />
| type="{}"}<br />
{ 36 } Hz<br />
||Correct<br />
<br />
{ If a sound has a frequency of 27 Hz, what frequency should we sample at?<br />
| type="{}"}<br />
{ 54 } Hz<br />
<br />
{ Which of the following are advantages of audio streaming?<br />
| type="[]"}<br />
+ It reduces piracy<br />
- You can listen to all the audio without interruption<br />
|| If the connection is lost you need to reconnect to listen to the other parts of the file<br />
- You can instantly start listening<br />
|| The audio must buffer first<br />
+ You do not need to download the whole file<br />
<br />
{You record 10 seconds of audio, setting the sample rate to 44.1kHz and using 16 bits per sample. Calculate the file size.<br />
| type="{}"}<br />
{ 882 } KB<br />
<br />
{How is an analogue wave described ? <br />
| type="()"}<br />
- A digital wave that cannot be produced by humans<br />
||Incorrect<br />
- A digital wave that can be produced by humans<br />
||Incorrect<br />
+ A smooth wave that can be produced by humans<br />
||Correct<br />
- A smooth wave that cannot be produced by humans<br />
||Incorrect<br />
<br />
</quiz></div>000032680https://www.trccompsci.online/mediawiki/index.php?title=Sound&diff=7346Sound2019-10-16T08:45:30Z<p>000032680: /* Revision Questions */</p>
<hr />
<div>=Overview=<br />
===Computer Science Tutor===<br />
<youtube>HlOTuCFtuV8</youtube><br />
<br />
https://www.youtube.com/watch?v=HlOTuCFtuV8&list=PL04uZ7242_M6O_6ITD6ncf7EonVHyBeCm&index=9<br />
<br />
===TRC PowerPoint===<br />
[https://studentthomrothac-my.sharepoint.com/:p:/g/personal/wayne_jones_thomroth_ac_uk/Ebzu5zwPN85NnUj6124W7AgBMe8qBBKxLOG0yw3HP20_hg?e=N811yn Sound]<br />
<br />
==Converting Analogue to Digital Sound==<br />
<br />
The following image demonstrates how sound files are created when they are inputted through devices such as a microphone:<br />
<br />
[[File:600px-Analogue_Digital_Conversion.png]]<br />
<br />
further explanation:<br />
<br />
<youtube>https://www.youtube.com/watch?v=VyqGzUbTphs&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4&index=1</youtube><br />
<br />
https://www.youtube.com/watch?v=VyqGzUbTphs&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4&index=1<br />
<br />
==Representing Sound==<br />
<br />
To store sound, a digitizer is needed to convert the analogue sound into digital sound. An analogue to digital converter carries out these conversions. 16 bit ADC is enough for CD quality sound. For High-Res audio, you can get audio files that are at 24 bit.<br />
<br />
[[File:Sound Samples.gif]]<br />
<br />
====Sampling Rate====<br />
<br />
The sampling rate or frequency is the number of samples taken per second. It is measured in hertz (Hz). The higher the sampling rate the more accurate the representation of the sound. But the higher the sampling rate, the bigger the file size will be as there will be more data the is being stored<br />
<br />
[[File:Sound SamplingRate.jpg|200px]]<br />
<br />
====Sampling Resolution====<br />
<br />
The sampling resolution is the number of bits assigned to each sample. The number of bits assigned allows for a wider range of sounds to be displayed. For example, if only one bit is used it can only be either 1 or 0, giving an option of only two different sounds, where as if 8 bits are used there are a possible 255 different sounds that can be recorded and then replayed. In a way, your PC bleeper speaker is one bit as it only produces one tone when there is a error on your computer and then your actual speakers that you listen to music to will be 8 bit sound as you can play 255 different sounds on it.<br />
<br />
====Additional Video====<br />
<br />
<youtube>https://www.youtube.com/watch?v=v7RwEnirp7I&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=v7RwEnirp7I&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
<br />
====Calculating File Size====<br />
A sound is sampled at 5kHz (5000Hz) and the sample resolution is 16 bits:<br />
<br />
# There is 5000 samples per second & each sample is 2 byte (16 bits)<br />
# 1 second of sound will be 5000 x 2 = 10,000 Bytes<br />
# 10 seconds of sound will be 5000 x 20 = 100,000 Bytes<br />
<br />
<youtube>https://www.youtube.com/watch?v=al5HsKIRhQw&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=al5HsKIRhQw&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
<br />
====Sampling Process====<br />
<br />
Pulse Amplitude Modulation (PAM) is the process which samples analogue signals and produces electrical pulses of height proportional to the signal's original amplitude.<br />
<br />
Pulse Code Modulation (PCM) is the process of coding sampled analogue signals by recording the height of each sample in binary.<br />
PCM pulses can then be encoded in binary form.<br />
<br />
== Nyquist's Theorem ==<br />
<br />
In 1928 Harry Nyquist found that in order to sample any sound at a similar quality to how it is in real life, you must use a sampling rate at double the frequency of the original sound. The result will be the closest possible to the original sound, because recording at double the frequency allows for all of the changes in the sound such as pitch to be captured digitally at a high quality.<br />
<br />
== MIDI Data ==<br />
<br />
MIDI stands for Musical Instrument Digital Interface.<br />
<br />
MIDI does a completely different approach to other sound recording methods. Instead of recording sound and then storing it in a digital format, It actually writes out a set of instructions which can be used to synthesize the sound that is listened to.<br />
This relies solely on pre-recorded digital samples and synthesized samples of sounds created by different instruments.<br />
<br />
The advantages of using MIDI instead of conventional recording methods is that firstly, it is a fraction of the size of a digital recorded version, it is easily edited or manipulated and notes can be passed to a different instrument and so the attributes of each note can be altered.<br />
<br />
<youtube>https://www.youtube.com/watch?v=AvqP3BhO0d8&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=AvqP3BhO0d8&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
<br />
== Audio Compression ==<br />
<br />
Audio compression is used to lower the storage space that a digital sound file takes up by removing sounds that humans won't be able to pick up listening to it. For example, in a song with guitar and drums, when there is a loud drum hit, the guitar will often be drowned out and could even become completely inaudible, so this data is removed to reduce the size of the audio file so it takes up less storage space, which is useful for devices like phones with a limited storage space. It is also useful for streaming music as it reduces the chance of the music buffering by reducing the amount of data which needs to be sent allowing for smoother more consistent listening.<br />
<br />
== Audio Streaming ==<br />
<br />
Audio streaming is a way in which audio/sound is broadcast to a user. It allows a user to listen to an audio file or watch a video without downloading the whole file, they only download a bit at a time... Which is the buffer.<br />
<br />
Audio Streaming has a delayed start in order to allow it to buffer, it also plays sound from the buffer and has seamless play unless connection to the host is lost. Audio Streaming saves space on the hard drive since the file is no longer required to be downloaded on the device for it be viewed, Which also means piracy is reduced.<br />
<br />
Audio streaming is so widely used and respected because of its usefulness. Before Audio Streaming was around, it could take you quite a while to listen to music/sound since you would have to download the whole file. Whereas Audio Streaming simply gives you the data that you need at that specific time and downloads the next when you need it. It does this simply by holding the data in the buffer.<br />
<br />
== Synthesising Sound ==<br />
<br />
Sound can be synthesised with MIDI (Musical Instrument Digital Interface), which records information about each note - such as duration, pitch, tempo, instrument and volume - and recreates that note when played. When using MIDI it is hard to replecate the proper soud as it would have to be played through note by note and would be a synthetic sound, in some cases it's good like in pop music but in other cases usually not. A MIDI link can hold up to 16 channels of information which can be routed to a seperate device for each channel.<br />
<br />
<br />
=Revision Questions=<br />
'''try to add more questions on:<br />
*file size calculations<br />
*ADC to DAC<br />
*Synthesising Sound<br />
*more detailed midi questions<br />
<br />
'''Also '||' is the feedback for an answer, and could be greatly improved'''<br />
<br />
<quiz display=simple><br />
{ How many bits is enough for CD quality audio? <br />
| type="()" }<br />
+ 16 bit<br />
||Correct, you only need 16 bits to achieve CD quality audio.<br />
- 24 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
- 32 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
- 64 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
<br />
{ According to Nyquist's Theorem, what should our sampling rate be?<br />
| type="()" }<br />
- Half the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
- The same as the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
+ Double the original rate.<br />
||Correct, sampling at double the rate of the original audio will achieve the closest match.<br />
- Triple the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
<br />
{ Which of the following are examples of audio file formats?<br />
| type="[]" }<br />
+ .mp3<br />
||Correct, mp3 represents ''MPEG-1 or MPEG-2 Audio Layer III'' audio file format.<br />
+ .wav<br />
||Correct, wav represents ''Waveform Audio File Format''.<br />
- .bmp<br />
||Incorrect, bmp represents ''Bitmap Image File'', which is an image file format.<br />
- .smf<br />
||Incorrect, smf represents ''Standard MIDI Format'', which is used to store MIDI information.<br />
<br />
{ How many information channels can a MIDI link hold?<br />
| type="()" }<br />
- 8<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
+ 16<br />
||Correct, a MIDI link can hold 16 channels of information.<br />
- 32<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
- 64<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
<br />
{If the audio you want to sample is at 44hz, what frequency should you sample at?<br />
|type="{}"}<br />
{ 88 _3 } hz.<br />
<br />
{What does MIDI stand for?<br />
| type="()" }<br />
- Musical Intelligent Dialogue Interface<br />
+ Musical Instrument Digital Interface<br />
- Muselk Instrument Digital Interface<br />
|| Muselk is an overwatch youtuber subscribe at https://www.youtube.com/channel/UCd534c_ehOvrLVL2v7Nl61w<br />
- Musical Instrument Detection Interface<br />
<br />
{Does this sample rate give a good representation of the wave? <br />
<br />
[[File:Sample rate.png]]<br />
| type="()" }<br />
-Yes<br />
+No<br />
<br />
<br />
{ A sound is sampled at 3KHz with a sample resolution of 8 bits. How many bytes will be used for 5 seconds of sound?<br />
| type="()" }<br />
- 120000<br />
|| That is the amount of bits used<br />
- 24000<br />
|| That is only for 1 second, and in bits<br />
+ 15000<br />
|| Correct answer<br />
- 1875<br />
|| Incorrect!<br />
<br />
|| '''How to calculate'''<br />
|| Number of bits / Number of bits in a byte, 8/8 = 1<br />
|| Samples = sample rate in hertz, 3*1000 = 3000<br />
|| 5 seconds of sound<br />
|| 3000 * 1 * 5 = 15000<br />
<br />
{ A sound is sampled at 6KHz with a sample resolution of 12 bits. How many bytes will be used for 3 seconds of sound?<br />
| type="()" }<br />
- 216000<br />
|| That is the amount of bits used<br />
+ 27000<br />
|| Correct answer<br />
- 18000<br />
|| You ignored the sample resolution<br />
- 9000<br />
|| That is only for 1 second<br />
<br />
|| '''How to calculate'''<br />
|| Number of bits / Number of bits in a byte, 12/8 = 1.5<br />
|| Samples = sample rate in hertz, 6*1000 = 6000<br />
|| 3 seconds of sound<br />
|| 6000 * 1.5 * 3 = 27000<br />
<br />
{ If an audio is sampled at 72 Hz, what frequency should the original sound have? <br />
| type="{}"}<br />
{ 36 } Hz<br />
<br />
{ If a sound has a frequency of 27 Hz, what frequency should we sample at?<br />
| type="{}"}<br />
{ 54 } Hz<br />
<br />
{ Which of the following are advantages of audio streaming?<br />
| type="[]"}<br />
+ It reduces piracy<br />
- You can listen to all the audio without interruption<br />
|| If the connection is lost you need to reconnect to listen to the other parts of the file<br />
- You can instantly start listening<br />
|| The audio must buffer first<br />
+ You do not need to download the whole file<br />
<br />
{You record 10 seconds of audio, setting the sample rate to 44.1kHz and using 16 bits per sample. Calculate the file size.<br />
| type="{}"}<br />
{ 882 } KB<br />
<br />
{How is an analogue wave described ? <br />
| type="()"}<br />
- A digital wave that cannot be produced by humans<br />
- A digital wave that can be produced by humans<br />
+ A smooth wave that can be produced by humans<br />
- A smooth wave that cannot be produced by humans<br />
<br />
</quiz></div>000032680https://www.trccompsci.online/mediawiki/index.php?title=Sound&diff=7343Sound2019-10-16T08:42:57Z<p>000032680: /* Revision Questions */</p>
<hr />
<div>=Overview=<br />
===Computer Science Tutor===<br />
<youtube>HlOTuCFtuV8</youtube><br />
<br />
https://www.youtube.com/watch?v=HlOTuCFtuV8&list=PL04uZ7242_M6O_6ITD6ncf7EonVHyBeCm&index=9<br />
<br />
===TRC PowerPoint===<br />
[https://studentthomrothac-my.sharepoint.com/:p:/g/personal/wayne_jones_thomroth_ac_uk/Ebzu5zwPN85NnUj6124W7AgBMe8qBBKxLOG0yw3HP20_hg?e=N811yn Sound]<br />
<br />
==Converting Analogue to Digital Sound==<br />
<br />
The following image demonstrates how sound files are created when they are inputted through devices such as a microphone:<br />
<br />
[[File:600px-Analogue_Digital_Conversion.png]]<br />
<br />
further explanation:<br />
<br />
<youtube>https://www.youtube.com/watch?v=VyqGzUbTphs&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4&index=1</youtube><br />
<br />
https://www.youtube.com/watch?v=VyqGzUbTphs&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4&index=1<br />
<br />
==Representing Sound==<br />
<br />
To store sound, a digitizer is needed to convert the analogue sound into digital sound. An analogue to digital converter carries out these conversions. 16 bit ADC is enough for CD quality sound. For High-Res audio, you can get audio files that are at 24 bit.<br />
<br />
[[File:Sound Samples.gif]]<br />
<br />
====Sampling Rate====<br />
<br />
The sampling rate or frequency is the number of samples taken per second. It is measured in hertz (Hz). The higher the sampling rate the more accurate the representation of the sound. But the higher the sampling rate, the bigger the file size will be as there will be more data the is being stored<br />
<br />
[[File:Sound SamplingRate.jpg|200px]]<br />
<br />
====Sampling Resolution====<br />
<br />
The sampling resolution is the number of bits assigned to each sample. The number of bits assigned allows for a wider range of sounds to be displayed. For example, if only one bit is used it can only be either 1 or 0, giving an option of only two different sounds, where as if 8 bits are used there are a possible 255 different sounds that can be recorded and then replayed. In a way, your PC bleeper speaker is one bit as it only produces one tone when there is a error on your computer and then your actual speakers that you listen to music to will be 8 bit sound as you can play 255 different sounds on it.<br />
<br />
====Additional Video====<br />
<br />
<youtube>https://www.youtube.com/watch?v=v7RwEnirp7I&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=v7RwEnirp7I&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
<br />
====Calculating File Size====<br />
A sound is sampled at 5kHz (5000Hz) and the sample resolution is 16 bits:<br />
<br />
# There is 5000 samples per second & each sample is 2 byte (16 bits)<br />
# 1 second of sound will be 5000 x 2 = 10,000 Bytes<br />
# 10 seconds of sound will be 5000 x 20 = 100,000 Bytes<br />
<br />
<youtube>https://www.youtube.com/watch?v=al5HsKIRhQw&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=al5HsKIRhQw&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
<br />
====Sampling Process====<br />
<br />
Pulse Amplitude Modulation (PAM) is the process which samples analogue signals and produces electrical pulses of height proportional to the signal's original amplitude.<br />
<br />
Pulse Code Modulation (PCM) is the process of coding sampled analogue signals by recording the height of each sample in binary.<br />
PCM pulses can then be encoded in binary form.<br />
<br />
== Nyquist's Theorem ==<br />
<br />
In 1928 Harry Nyquist found that in order to sample any sound at a similar quality to how it is in real life, you must use a sampling rate at double the frequency of the original sound. The result will be the closest possible to the original sound, because recording at double the frequency allows for all of the changes in the sound such as pitch to be captured digitally at a high quality.<br />
<br />
== MIDI Data ==<br />
<br />
MIDI stands for Musical Instrument Digital Interface.<br />
<br />
MIDI does a completely different approach to other sound recording methods. Instead of recording sound and then storing it in a digital format, It actually writes out a set of instructions which can be used to synthesize the sound that is listened to.<br />
This relies solely on pre-recorded digital samples and synthesized samples of sounds created by different instruments.<br />
<br />
The advantages of using MIDI instead of conventional recording methods is that firstly, it is a fraction of the size of a digital recorded version, it is easily edited or manipulated and notes can be passed to a different instrument and so the attributes of each note can be altered.<br />
<br />
<youtube>https://www.youtube.com/watch?v=AvqP3BhO0d8&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=AvqP3BhO0d8&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
<br />
== Audio Compression ==<br />
<br />
Audio compression is used to lower the storage space that a digital sound file takes up by removing sounds that humans won't be able to pick up listening to it. For example, in a song with guitar and drums, when there is a loud drum hit, the guitar will often be drowned out and could even become completely inaudible, so this data is removed to reduce the size of the audio file so it takes up less storage space, which is useful for devices like phones with a limited storage space. It is also useful for streaming music as it reduces the chance of the music buffering by reducing the amount of data which needs to be sent allowing for smoother more consistent listening.<br />
<br />
== Audio Streaming ==<br />
<br />
Audio streaming is a way in which audio/sound is broadcast to a user. It allows a user to listen to an audio file or watch a video without downloading the whole file, they only download a bit at a time... Which is the buffer.<br />
<br />
Audio Streaming has a delayed start in order to allow it to buffer, it also plays sound from the buffer and has seamless play unless connection to the host is lost. Audio Streaming saves space on the hard drive since the file is no longer required to be downloaded on the device for it be viewed, Which also means piracy is reduced.<br />
<br />
Audio streaming is so widely used and respected because of its usefulness. Before Audio Streaming was around, it could take you quite a while to listen to music/sound since you would have to download the whole file. Whereas Audio Streaming simply gives you the data that you need at that specific time and downloads the next when you need it. It does this simply by holding the data in the buffer.<br />
<br />
== Synthesising Sound ==<br />
<br />
Sound can be synthesised with MIDI (Musical Instrument Digital Interface), which records information about each note - such as duration, pitch, tempo, instrument and volume - and recreates that note when played. When using MIDI it is hard to replecate the proper soud as it would have to be played through note by note and would be a synthetic sound, in some cases it's good like in pop music but in other cases usually not. A MIDI link can hold up to 16 channels of information which can be routed to a seperate device for each channel.<br />
<br />
<br />
=Revision Questions=<br />
'''try to add more questions on:<br />
*file size calculations<br />
*ADC to DAC<br />
*Synthesising Sound<br />
*more detailed midi questions<br />
<br />
'''Also '||' is the feedback for an answer, and could be greatly improved'''<br />
<br />
<quiz display=simple><br />
{ How many bits is enough for CD quality audio? <br />
| type="()" }<br />
+ 16 bit<br />
||Correct, you only need 16 bits to achieve CD quality audio.<br />
- 24 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
- 32 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
- 64 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
<br />
{ According to Nyquist's Theorem, what should our sampling rate be?<br />
| type="()" }<br />
- Half the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
- The same as the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
+ Double the original rate.<br />
||Correct, sampling at double the rate of the original audio will achieve the closest match.<br />
- Triple the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
<br />
{ Which of the following are examples of audio file formats?<br />
| type="[]" }<br />
+ .mp3<br />
||Correct, mp3 represents ''MPEG-1 or MPEG-2 Audio Layer III'' audio file format.<br />
+ .wav<br />
||Correct, wav represents ''Waveform Audio File Format''.<br />
- .bmp<br />
||Incorrect, bmp represents ''Bitmap Image File'', which is an image file format.<br />
- .smf<br />
||Incorrect, smf represents ''Standard MIDI Format'', which is used to store MIDI information.<br />
<br />
{ How many information channels can a MIDI link hold?<br />
| type="()" }<br />
- 8<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
+ 16<br />
||Correct, a MIDI link can hold 16 channels of information.<br />
- 32<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
- 64<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
<br />
{If the audio you want to sample is at 44hz, what frequency should you sample at?<br />
|type="{}"}<br />
{ 88 _3 } hz.<br />
<br />
{What does MIDI stand for?<br />
| type="()" }<br />
- Musical Intelligent Dialogue Interface<br />
+ Musical Instrument Digital Interface<br />
- Muselk Instrument Digital Interface<br />
|| Muselk is an overwatch youtuber subscribe at https://www.youtube.com/channel/UCd534c_ehOvrLVL2v7Nl61w<br />
- Musical Instrument Detection Interface<br />
<br />
{Does this sample rate give a good representation of the wave? <br />
<br />
[[File:Sample rate.png]]<br />
| type="()" }<br />
-Yes<br />
+No<br />
<br />
<br />
{ A sound is sampled at 3KHz with a sample resolution of 8 bits. How many bytes will be used for 5 seconds of sound?<br />
| type="()" }<br />
- 120000<br />
|| That is the amount of bits used<br />
- 24000<br />
|| That is only for 1 second, and in bits<br />
+ 15000<br />
|| Correct answer<br />
- 1875<br />
|| Incorrect!<br />
<br />
|| '''How to calculate'''<br />
|| Number of bits / Number of bits in a byte, 8/8 = 1<br />
|| Samples = sample rate in hertz, 3*1000 = 3000<br />
|| 5 seconds of sound<br />
|| 3000 * 1 * 5 = 15000<br />
<br />
{ A sound is sampled at 6KHz with a sample resolution of 12 bits. How many bytes will be used for 3 seconds of sound?<br />
| type="()" }<br />
- 216000<br />
|| That is the amount of bits used<br />
+ 27000<br />
|| Correct answer<br />
- 18000<br />
|| You ignored the sample resolution<br />
- 9000<br />
|| That is only for 1 second<br />
<br />
|| '''How to calculate'''<br />
|| Number of bits / Number of bits in a byte, 12/8 = 1.5<br />
|| Samples = sample rate in hertz, 6*1000 = 6000<br />
|| 3 seconds of sound<br />
|| 6000 * 1.5 * 3 = 27000<br />
<br />
{ If an audio is sampled at 72 Hz, what frequency should the original sound have? <br />
| type="{}"}<br />
{ 36 } Hz<br />
<br />
{ If a sound has a frequency of 27 Hz, what frequency should we sample at?<br />
| type="{}"}<br />
{ 54 } Hz<br />
<br />
{ Which of the following are advantages of audio streaming?<br />
| type="[]"}<br />
+ It reduces piracy<br />
- You can listen to all the audio without interruption<br />
|| If the connection is lost you need to reconnect to listen to the other parts of the file<br />
- You can instantly start listening<br />
|| The audio must buffer first<br />
+ You do not need to download the whole file<br />
<br />
{You record 10 seconds of audio, setting the sample rate to 44.1kHz and using 16 bits per sample. Calculate the file size.<br />
| type="{}"}<br />
{ 882 } KB<br />
<br />
{How is an analogue wave described ? <br />
| type="()"}<br />
- A wave that is a digital wave and cannot be produced by humans<br />
- A wave that is a digital wave that can be produced by humans<br />
+ A wave that is a smooth wave that can be produced by humans<br />
- A wave that is a smooth wave that cannot be produced by humans<br />
<br />
</quiz></div>000032680https://www.trccompsci.online/mediawiki/index.php?title=Sound&diff=7342Sound2019-10-16T08:41:53Z<p>000032680: </p>
<hr />
<div>=Overview=<br />
===Computer Science Tutor===<br />
<youtube>HlOTuCFtuV8</youtube><br />
<br />
https://www.youtube.com/watch?v=HlOTuCFtuV8&list=PL04uZ7242_M6O_6ITD6ncf7EonVHyBeCm&index=9<br />
<br />
===TRC PowerPoint===<br />
[https://studentthomrothac-my.sharepoint.com/:p:/g/personal/wayne_jones_thomroth_ac_uk/Ebzu5zwPN85NnUj6124W7AgBMe8qBBKxLOG0yw3HP20_hg?e=N811yn Sound]<br />
<br />
==Converting Analogue to Digital Sound==<br />
<br />
The following image demonstrates how sound files are created when they are inputted through devices such as a microphone:<br />
<br />
[[File:600px-Analogue_Digital_Conversion.png]]<br />
<br />
further explanation:<br />
<br />
<youtube>https://www.youtube.com/watch?v=VyqGzUbTphs&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4&index=1</youtube><br />
<br />
https://www.youtube.com/watch?v=VyqGzUbTphs&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4&index=1<br />
<br />
==Representing Sound==<br />
<br />
To store sound, a digitizer is needed to convert the analogue sound into digital sound. An analogue to digital converter carries out these conversions. 16 bit ADC is enough for CD quality sound. For High-Res audio, you can get audio files that are at 24 bit.<br />
<br />
[[File:Sound Samples.gif]]<br />
<br />
====Sampling Rate====<br />
<br />
The sampling rate or frequency is the number of samples taken per second. It is measured in hertz (Hz). The higher the sampling rate the more accurate the representation of the sound. But the higher the sampling rate, the bigger the file size will be as there will be more data the is being stored<br />
<br />
[[File:Sound SamplingRate.jpg|200px]]<br />
<br />
====Sampling Resolution====<br />
<br />
The sampling resolution is the number of bits assigned to each sample. The number of bits assigned allows for a wider range of sounds to be displayed. For example, if only one bit is used it can only be either 1 or 0, giving an option of only two different sounds, where as if 8 bits are used there are a possible 255 different sounds that can be recorded and then replayed. In a way, your PC bleeper speaker is one bit as it only produces one tone when there is a error on your computer and then your actual speakers that you listen to music to will be 8 bit sound as you can play 255 different sounds on it.<br />
<br />
====Additional Video====<br />
<br />
<youtube>https://www.youtube.com/watch?v=v7RwEnirp7I&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=v7RwEnirp7I&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
<br />
====Calculating File Size====<br />
A sound is sampled at 5kHz (5000Hz) and the sample resolution is 16 bits:<br />
<br />
# There is 5000 samples per second & each sample is 2 byte (16 bits)<br />
# 1 second of sound will be 5000 x 2 = 10,000 Bytes<br />
# 10 seconds of sound will be 5000 x 20 = 100,000 Bytes<br />
<br />
<youtube>https://www.youtube.com/watch?v=al5HsKIRhQw&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
<br />
https://www.youtube.com/watch?v=al5HsKIRhQw&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
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====Sampling Process====<br />
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Pulse Amplitude Modulation (PAM) is the process which samples analogue signals and produces electrical pulses of height proportional to the signal's original amplitude.<br />
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Pulse Code Modulation (PCM) is the process of coding sampled analogue signals by recording the height of each sample in binary.<br />
PCM pulses can then be encoded in binary form.<br />
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== Nyquist's Theorem ==<br />
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In 1928 Harry Nyquist found that in order to sample any sound at a similar quality to how it is in real life, you must use a sampling rate at double the frequency of the original sound. The result will be the closest possible to the original sound, because recording at double the frequency allows for all of the changes in the sound such as pitch to be captured digitally at a high quality.<br />
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== MIDI Data ==<br />
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MIDI stands for Musical Instrument Digital Interface.<br />
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MIDI does a completely different approach to other sound recording methods. Instead of recording sound and then storing it in a digital format, It actually writes out a set of instructions which can be used to synthesize the sound that is listened to.<br />
This relies solely on pre-recorded digital samples and synthesized samples of sounds created by different instruments.<br />
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The advantages of using MIDI instead of conventional recording methods is that firstly, it is a fraction of the size of a digital recorded version, it is easily edited or manipulated and notes can be passed to a different instrument and so the attributes of each note can be altered.<br />
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<youtube>https://www.youtube.com/watch?v=AvqP3BhO0d8&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4</youtube><br />
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https://www.youtube.com/watch?v=AvqP3BhO0d8&list=PLCiOXwirraUA69WUAMYyFicC5qbQ4PGc4<br />
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== Audio Compression ==<br />
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Audio compression is used to lower the storage space that a digital sound file takes up by removing sounds that humans won't be able to pick up listening to it. For example, in a song with guitar and drums, when there is a loud drum hit, the guitar will often be drowned out and could even become completely inaudible, so this data is removed to reduce the size of the audio file so it takes up less storage space, which is useful for devices like phones with a limited storage space. It is also useful for streaming music as it reduces the chance of the music buffering by reducing the amount of data which needs to be sent allowing for smoother more consistent listening.<br />
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== Audio Streaming ==<br />
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Audio streaming is a way in which audio/sound is broadcast to a user. It allows a user to listen to an audio file or watch a video without downloading the whole file, they only download a bit at a time... Which is the buffer.<br />
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Audio Streaming has a delayed start in order to allow it to buffer, it also plays sound from the buffer and has seamless play unless connection to the host is lost. Audio Streaming saves space on the hard drive since the file is no longer required to be downloaded on the device for it be viewed, Which also means piracy is reduced.<br />
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Audio streaming is so widely used and respected because of its usefulness. Before Audio Streaming was around, it could take you quite a while to listen to music/sound since you would have to download the whole file. Whereas Audio Streaming simply gives you the data that you need at that specific time and downloads the next when you need it. It does this simply by holding the data in the buffer.<br />
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== Synthesising Sound ==<br />
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Sound can be synthesised with MIDI (Musical Instrument Digital Interface), which records information about each note - such as duration, pitch, tempo, instrument and volume - and recreates that note when played. When using MIDI it is hard to replecate the proper soud as it would have to be played through note by note and would be a synthetic sound, in some cases it's good like in pop music but in other cases usually not. A MIDI link can hold up to 16 channels of information which can be routed to a seperate device for each channel.<br />
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=Revision Questions=<br />
'''try to add more questions on:<br />
*file size calculations<br />
*ADC to DAC<br />
*Synthesising Sound<br />
*more detailed midi questions<br />
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'''Also '||' is the feedback for an answer, and could be greatly improved'''<br />
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<quiz display=simple><br />
{ How many bits is enough for CD quality audio? <br />
| type="()" }<br />
+ 16 bit<br />
||Correct, you only need 16 bits to achieve CD quality audio.<br />
- 24 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
- 32 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
- 64 bit<br />
||Incorrect, you only need 16 bits to achieve CD quality audio.<br />
<br />
{ According to Nyquist's Theorem, what should our sampling rate be?<br />
| type="()" }<br />
- Half the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
- The same as the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
+ Double the original rate.<br />
||Correct, sampling at double the rate of the original audio will achieve the closest match.<br />
- Triple the original rate.<br />
||Incorrect, sampling at double the rate of the original audio will achieve the closest match.<br />
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{ Which of the following are examples of audio file formats?<br />
| type="[]" }<br />
+ .mp3<br />
||Correct, mp3 represents ''MPEG-1 or MPEG-2 Audio Layer III'' audio file format.<br />
+ .wav<br />
||Correct, wav represents ''Waveform Audio File Format''.<br />
- .bmp<br />
||Incorrect, bmp represents ''Bitmap Image File'', which is an image file format.<br />
- .smf<br />
||Incorrect, smf represents ''Standard MIDI Format'', which is used to store MIDI information.<br />
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{ How many information channels can a MIDI link hold?<br />
| type="()" }<br />
- 8<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
+ 16<br />
||Correct, a MIDI link can hold 16 channels of information.<br />
- 32<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
- 64<br />
||Incorrect, a MIDI link can hold 16 channels of information.<br />
<br />
{If the audio you want to sample is at 44hz, what frequency should you sample at?<br />
|type="{}"}<br />
{ 88 _3 } hz.<br />
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{What does MIDI stand for?<br />
| type="()" }<br />
- Musical Intelligent Dialogue Interface<br />
+ Musical Instrument Digital Interface<br />
- Muselk Instrument Digital Interface<br />
|| Muselk is an overwatch youtuber subscribe at https://www.youtube.com/channel/UCd534c_ehOvrLVL2v7Nl61w<br />
- Musical Instrument Detection Interface<br />
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{Does this sample rate give a good representation of the wave? <br />
<br />
[[File:Sample rate.png]]<br />
| type="()" }<br />
-Yes<br />
+No<br />
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<br />
{ A sound is sampled at 3KHz with a sample resolution of 8 bits. How many bytes will be used for 5 seconds of sound?<br />
| type="()" }<br />
- 120000<br />
|| That is the amount of bits used<br />
- 24000<br />
|| That is only for 1 second, and in bits<br />
+ 15000<br />
|| Correct answer<br />
- 1875<br />
|| Incorrect!<br />
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|| '''How to calculate'''<br />
|| Number of bits / Number of bits in a byte, 8/8 = 1<br />
|| Samples = sample rate in hertz, 3*1000 = 3000<br />
|| 5 seconds of sound<br />
|| 3000 * 1 * 5 = 15000<br />
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{ A sound is sampled at 6KHz with a sample resolution of 12 bits. How many bytes will be used for 3 seconds of sound?<br />
| type="()" }<br />
- 216000<br />
|| That is the amount of bits used<br />
+ 27000<br />
|| Correct answer<br />
- 18000<br />
|| You ignored the sample resolution<br />
- 9000<br />
|| That is only for 1 second<br />
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|| '''How to calculate'''<br />
|| Number of bits / Number of bits in a byte, 12/8 = 1.5<br />
|| Samples = sample rate in hertz, 6*1000 = 6000<br />
|| 3 seconds of sound<br />
|| 6000 * 1.5 * 3 = 27000<br />
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{ If an audio is sampled at 72 Hz, what frequency should the original sound have? <br />
| type="{}"}<br />
{ 36 } Hz<br />
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{ If a sound has a frequency of 27 Hz, what frequency should we sample at?<br />
| type="{}"}<br />
{ 54 } Hz<br />
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{ Which of the following are advantages of audio streaming?<br />
| type="[]"}<br />
+ It reduces piracy<br />
- You can listen to all the audio without interruption<br />
|| If the connection is lost you need to reconnect to listen to the other parts of the file<br />
- You can instantly start listening<br />
|| The audio must buffer first<br />
+ You do not need to download the whole file<br />
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{You record 10 seconds of audio, setting the sample rate to 44.1kHz and using 16 bits per sample. Calculate the file size.| type="{}"}<br />
{ 882 } KB<br />
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{How is an analogue wave described ? <br />
| type="()"}<br />
- A wave that is a digital wave and cannot be produced by humans<br />
- A wave that is a digital wave that can be produced by humans<br />
+ A wave that is a smooth wave that can be produced by humans<br />
- A wave that is a smooth wave that cannot be produced by humans<br />
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</quiz></div>000032680