1 A PAM system is used to multiplex 5 channels each of which

1. A PAM system is used to multiplex 5 channels, each of which has a baseband bandwidth of 2 kHz. assuming the minimum theoretical sampling rate , and ignoring sync pulses, determine the minimum transmission bandwidth (in kHz).

a(2) b(1) c(4) d(20) e(10)

2. For the system of the preceding problem, assume that PWM is used instead. An arbitrary criterion is established that the rise time cannot exceeded 2%of each pulse time interval. Determine the minumum transmission bandwidth (in kHz).

3. For the system of problem 1, assume that each sample is converted to 8-bit digital words. This means that there were 8 pulses occupying the width of each sample. Determine the minimum transmission band width(inkHz)

Solution

Ts= sampling period=1/(2*2) ms= 1/4 ms

(1) Tb= bit duration= Ts/5

BW= transmission band width

=1/(2Tb)

= 5*2= 10 kHz

(3) n= number of bit= 8

Tb= bit duration of pulse= Ts/(8*5)

Transmission band width=1/(2*Tb)=4*5/Ts= 4*5*4= 80 khz