Figure 1.3: Breaking the source coding/decoding layer into 3 layers for a waveform
source. The input side of the outermost layer converts the waveform into a sequence
of samples and output side converts the recovered samples back to the waveform. The
quantizer then converts each sample into one of a finite set of symbols, and the peer
module recreates the sample (with some distortion). Finally the inner layer encodes
the sequence of symbols into binary digits.