20 s20 signals, each of bandwidth 5 kHz and peak-to-peak range of 4 V, are sampled at their Nyquist rates, quantized uniformly, encoded using PCM, multiplexed in time domain. The multiplexed stream has the rate of 2 Mbps.
(a) What is the number of levels used for quantization.
(b) When a DPCM is used instead of PCM, the peak-to-peak range of differential values was found to be 0.25 V.
(i) How much improvement in SNR (in dB) was achieved by DPCM over PCM?
(ii) We want to exchange this improvement in SNR for reducing the transmission rate. What would be the minimum transmission rate of the multiplexed stream while maintaining SNR quality at least as good as that of the PCM system.