a squelch system for use in a multicarrier communications receiver includes a conventional noise squelch circuit having a detector and filter operative to close a squelch gate in the absence of an incoming carrier and a phase locked loop means parallel thereto . the phase locked loop means does not lock onto noise signals but will lock onto carrier difference signals within its frequency range to open the squelch gate . a further improvement to the squelch system uses a threshold switch which parallels the above - mentioned conventional squelch circuit and phase locked loop means and comprised of a low pass filter and a comparator to maintain the squelch gate closed until the carrier portion of the receiver am audio signal is above a certain threshold .