A Synchronous Communications Receiver for the Military UHF Band

A synchronous receiver for double-sideband suppressed carrier signals in the 225-mc to 400-mc band is described. The receiver is suitable for voice or data link operation and provides automatic correction of Doppler shifts in the received signal. The "local carrier" oscillator is crystal stabilized at the IF frequency, and electronically tuned by a closed servo loop in which the locallygenerated carrier is compared with the received double-sideband signal. The parameters of the AFC loop have been designed to provide correction from plus or minus 5 kc. The development of this receiver represents a significant advance in the state of the communications art since it extends the advantages of suppressed carrier communications to high-performance aircraft in the UHF or higher frequency bands. The receiver development was sponsored by an Air Force (RADC) contract for development of a multiple-channel UHF transceiver for synchronous communication and is designated the AN/GRC-88 (XW-1).