Noise chopper for preventing false locks in a coherent carrier recovery system

摘要

A multiple phase shift keyed data coherent carrier recovery system wherein a coherent carrier tracking loop has attached thereto a signal generator for providing a signal with non-stationary zero-crossing times (e.g. a noise generator), which signal generator chops, or alters the phase of, signals within the loop to prevent the loop from locking on harmonics or subharmonics and to allow AC coupling with DC response therein.