scope:

The equipment specified herein is a solid state monitor which operates over the frequency range of 108 to 118 MHz. This monitor is intended for use in a Doppler VHF omnirange (VOR) facility. The monitor samples the signals of a carrier transmitter and of a sideband transmitter (transmitters not required to be furnished under this specification). Input signals consist of a carrier signal and (separate) upper and lower sideband signals which are nominally 9960 Hz removed from the carrier frequency. The monitor provides alarm outputs whenever the frequency of the sideband signals deviates from nominal beyond pre-established limits. Visual displays are provided of the sideband difference frequency and of alarm status.