DIGITAL MULTIFREQUENCY SIGNAL RECEIVER

摘要

DIGITAL MULTI FREQUENCY SIGNAL RECEIVER A digital multifrequency receiver circuit of the type employed between telephone system central offices, arranged to provide a faster response to received signals by processing the received signal tones digitally. The faster response resulting from the elimination of automatic gain control circuits and the use of a fixed gain amplifier used only when the received signal is below an acceptable level and the provision of variable threshold to the individual frequency comparator circuits.