Waves In Communication

Question 1

What is the amplitude of digital signals?

Answer 1

The signal can only have one amplitude

Question 2

What are some examples of digital signals?

Answer 2

Internet, mobile phone, Bluetooth, digital TV, digital radio

Question 3

What are digital signals made of?

Answer 3

Made up of binary digits or bits (10110)

Question 4

What is that amplitude of analogue signals?

Answer 4

Amplitude can vary

Question 5

What does ADC mean?

Answer 5

Analogue to digital converter

Question 6

What does a ADC do?

Answer 6

It uses a process called sampling

it looks at the value of the signal and converts to binary code

Question 7

What are the factors that affect the quality of digital signals?

Answer 7

Sampling rate - how many samples are taken per second

sampling sensitivity - how close together the samples are (how accurate the sampling will be)

Question 8

How is a picture converted into digital

Answer 8

The picture is split up into pixels

The colour of each pixel has a binary code

Question 9

What are the advantages of digital signals?

Answer 9

Digital signals can carry more information in the same bandwidth (the electromagnetic spectrum)

If it pick up interference it is easier to filter is out (because it’s easier to recognise it)

Computer memory and processing is digital

Question 10

What are the disadvantages of digital signals?

Answer 10

Signal processing takes time so there may be a delay (however nowadays this is not much of a problem due to lots of boardband)

Quality depends on sampling settings e.g sampling rate, number of pixels

Question 11

How do we avoid interfering with others signals?

Answer 11

The government allocates bandwidth to each one (part of the whole spectrum)

Phones can’t use the same bandwidth as radios