Problem on multiplexed channels

Question

4 channels, two with a bit-rate of 200 kbps and two with a bit-rate of 150 Kbps are to be multiplexed employing multiple slots TDM with no sync bits.

a. Find out the size of a frame in bits?

b. Determine frame rate?

c. Compute the duration of a frame?

d. Find out the data rate?

Answer 1

a. The frame takes 4 bits from each of first two sources and 3 bits from each of second two sources. Frame size = 4 × 2 + 3 × 2 = 14 bits

b. Each frame carries 4 bit from each 200-kbps source or 3 bits from each 150 kbps. Frame rate = 200,000/4 = 150,000 /3 = 50,000 frames/s

c. Frame duration = 1 / (frame rate) = 1 /50,000 = 20 μs

d. Output data rate = (50,000 frames/s) × (14 bits/frame) = 700 kbps