Overview and principle of waveform coding

It has the advantages of strong adaptability and good voice quality, but the coding rate is high, which is used in communication with less strict requirements on signal bandwidth, but this coding method is obviously not suitable for mobile communication with relatively tight frequency resources. Pulse code modulation (PCM) and incremental modulation (△M) and their improved adaptive incremental modulation (ADM) and adaptive differential coding (ADPCM) belong to waveform coding technology. They can give high coding quality at the rates of 64 and 16Kbit/s, respectively, and their performance will decline rapidly when the rate is further reduced.