Brief introduction of waveform coding

Waveform coding is to directly convert the time domain signal into digital coding, and try to keep the shape of the reconstructed speech waveform on the original speech signal waveform. The basic principle of waveform coding is to sample analog speech at a certain rate on the time axis, and then quantize the amplitude samples hierarchically and express them with codes. Decoding is the opposite process, and the received digital sequence is decoded and filtered to restore to an analog signal.