Chapter 4 - Digital Transmission

Question 1

How is digital audio transmitted between devices?

Answer 1

The binary information is transmitted using a square wave in the Megahertz range. The pulses of negative and positive voltage is interpreted as 1’s and 0’s.

Question 2

What is Jitter?

Answer 2

Jitter is a time based error. The square wave becomes distorted.

Question 3

What causes jitter?

Answer 3

Caused by varying time delays from component to component in the signal path.

Question 4

What are the 5 effects of Jitter?

Answer 4

• Increased “grain”
• Instruments losing their sharp edge and focus.
• Apparent loss of level
• Loss of low-level resolution caused by added noise
• Distortion added to the signal

Question 5

Name the 5 digital audio transmission formats.

Answer 5

• AES/ EBU
• S/PDIF
• MADI
• A-DAT OPTICAL
• Audio Over IP

Question 6

What is SDIF-2 used for?

Answer 6

Transmitting serial data between certain digital audio systems sold by Sony in the 1980’s. It is outdated.

Question 7

What does AES/EBU stand for?

Answer 7

Audio Engineering Society / European Broadcast Union.

Question 8

What is AES/EBU used for?

Answer 8

Used in professional audio. It is used to convey two-channel or monoaural audio over a shielded twisted pair of wires in a balanced configuration via 3 pin XLR cable. Operates by transmitting channel data and information as blocks of 192 bits. Data is transmitted in an A-B-A-B fashion.

Question 9

What does S/PDIF stand for?

Answer 9

Sony/Phillips Digital interface

Question 10

What is S/PDIF used for?

Answer 10

Digital audio transmission between consumer devices.

Question 11

How does S/PDIF work?

Answer 11

Very similar to AES/EBU. It uses unbalanced Phono (RCA) cables instead.

Question 12

Is S/PDIF balanced or unbalanced?

Answer 12

unbalanced

Question 13

Is AES/EBU balanced or unbalanced?

Answer 13

Balanced

Question 14

What does MADI stand for?

Answer 14

Multichannel Audio Digital Interface

Question 15

What is a MADI cable used for?

Answer 15

Connecting two digital multichannel devices such as a console and tape recorder.

Question 16

What is the maximum number of channels that MADI supports?

Answer 16

56

Question 17

What is the data transmission rate of MADI?

Answer 17

100-mega bits/second.

Question 18

How does Fiber Optic Transmission work?

Answer 18

It operates by propagating photons through a thin optically clear cable that can be made of either purified glass or plastic. The pulses of light on and off represent binary.

Question 19

What does ADAT stand for?

Answer 19

Alesis Multichannel Optical Digital Interface

Question 20

How does ADAT work?

Answer 20

The ADAT protocol conveys 8 channels of digital audio serial information along an optical fibre over short distances.

Question 21

What does AoIP stand for?

Answer 21

Audio Over IP

Question 22

What is Audio Over IP?

Answer 22

Distribution of digital audio over an IP network. (Internet or LAN)

Question 23

Name the 4 Digital Data Transmission Formats.

Answer 23

• LAN
• USB
• IEEE 1394 Firewire 400, Firewire 800
• Thunderbolt

Question 24

What was the main feature of USB 1.0?

Answer 24

Hot swap.

Question 25

What is USB 1.0 data transfer rate?

Answer 25

12 megabits per second.

Question 26

What is USB 2.0 data transfer rate?

Answer 26

480 mbps

Question 27

Which USB protocol does MIDI use?

Answer 27

USB 2.0

Question 28

What color is USB 3.0

Answer 28

Blue

Question 29

What is the Data transfer speed of USB 3.0?

Answer 29

5 Gbps

Question 30

What are the two revisions of IEEE 1394 firewire?

Answer 30

Firewire 400 and firewire 800

Question 31

What is Firewire?

Answer 31

The industry-standard implementation of Apple’s 1394 digital I/O system.

Question 32

How many devices can you connect with Firewire without additional hardware?

Answer 32

63

Question 33

What is the transfer speed of thunderbolt?

Answer 33

10Gbps