Abstract: An adaptive digital squelch system, responsive to ambient RF background noise, that automatically adjusts the receiver squelch level during intervals when no valid signal is being received. A valid signal is considered to be a signal that is greater than the receiver squelch level and which contains an audio signal at a specific frequency; otherwise, the signal is considered noise. When the invention detects the absence of a valid signal, the squelch level is periodically calculated by averaging multiple noise signal levels at multiple frequencies.