METHOD AND APPARATUS FOR RINGER DETECTION

摘要

The apparatus and method for detecting the presence of ringer signals in a telephone which samples the incoming telephone signals within a prescribed time interval, windows the signals, and computes a set of auto-correlation coefficients. These coefficients are normalized (58), and their absolute values (60) are calculated and summed (62) and compared with an empirically-derived threshold. If the coefficient sum exceeds the threshold (64), a high degree of correlation within incoming signals is indicated, distinguishing the incoming signal as containing ringer signal constituents.