Given an audio signal with spectral components in the frequency band 300 to 3,000 Hz, assume that a sampling rate of 7 kHz will be used to generate a PCM signal. Design an appropriate PCM system as follows:
(a) Design a block diagram of the PCM system, including the transmitter, channel and receiver.
(b) Specify the number of uniform quantization steps needed, assuming that the peak signal-to-noise ratio at the receiver output needs to be at least 30 dB and that polar NRZ signaling is used.
(c) Investigate how nonuniform quantization can be used to improve the performance of the system.