Adaptive differential pulse code modulation system.

摘要

An adaptive differential pulse code modulation system includes an adaptive quantizer (12) and an adaptive predictor (14) which have a coding characteristic optimized to a voice signal, and a quantizer (12) and a predictor (14) which have a coding characteristic optimized to a voice band MODEM signal. This system is normally used as a coding system optimized to the voice signal, and when this system detects a MODEM training signal, it becomes a coding system optimized to the MODEM signal.