Topic: Digital Communications
8 signals, each limited to 2 kHz and sampled at Nyquist rate, are converted into binary PCM signal using 256 quantization levels. The data rate for TDM signal will be:
- A. 256 kbps
- B. 32 kbps
- C. 128 kbps
- D. 512 kbps
Answer: A. 256 kbps
Explanation: Maximum frequency $f_m = 2$ kHz.
Nyquist sampling rate $f_s = 2 \times f_m = 4$ kHz.
Number of quantization levels $L = 256 = 2^n \Rightarrow n = 8$ bits/sample.
Bit rate for one signal = $n \times f_s = 8 \times 4$ kbps = 32 kbps.
For 8 multiplexed (TDM) signals, total data rate = $8 \times 32$ kbps = 256 kbps.