4.1.1: Line Coding

Question 1

What’s a data element? What’s a signal element?

Answer 1

A data element is the smallest entity that can represent a piece of information (a bit).

A signal element is the shortest unit (timewise) of a digital signal.

Question 2

What is the data-to-signal element ratio?

Answer 2

The number of data elements per signal element.

Question 3

What is data rate? What is signal rate?

Answer 3

Data rate is the number of data elements sent in one second (bps). We want to increase data rate.

Signal rate is the number of signal elements sent in one second (baud). We want to decrease signal rate.

Question 4

What’s the relationship between data rate (N) and signal rate (S)?

Answer 4

S = N / r

S = signal rate (baud)
N = data rate (bps)
r = ( data elements [bits] per signal element )

Question 5

What’s the expanded equation for data rate (N) and signal rate (S)?

Answer 5

S(avg) = c * N * (1/r)

S(avg) = signal rate (baud)
c = case factor
N = data rate (bps)
r = (data elements / signal element)

Question 6

What’s the equation to determine minimum bandwidth?

Answer 6

B(min) = c * N * (1/r)

B = bandwidth (Hz)
c = case factor
N = data rate (bps)
r = (data elements / signal element)

Question 7

What’s the equation to determine max data rate?

Answer 7

N(max) = (1/c) * B * r

N = data rate
c = case factor
B = bandwidth
r = (data elements / signal element)

Question 9

What is the equation for the bandwidth of a signal that has been converted from analog to digital?

Answer 9

B(min) = N(b) * B(analog)

Question 10

What is the equation for the bandwidth of a signal that has been converted from analog to digital?