MODEM SIGNAL DETECTING SYSTEM FOR ADAPTIVE DIFFERENTIAL PCM CODEC

摘要

A modem signal detecting system for an adaptive differential code modulation system, which is intended for detecting a modem training signal, comprises a comparison and decision circuit which receives an input signal from a signal power calculator and compares a signal power level during a silent period and a training period of a modem training signal. The comparison and decision circuit then decides whether or not the transmission quality of the transmission line is suitable for the modem communication.