PHASE-LOCK-STABILIZED SYSTEM FOR GENERATING CARRIER FREQUENCIES USABLE IN MULTIPLEX COMMUNICATION

摘要

A voltage-responsive carrier-frequency oscillator, with a limited range of adjustability designed to compensate for frequency drifts, works through a frequency divider into a phase comparator also receiving a relatively low base frequency harmonically related to the desired carrier frequency. The output of the phase comparator is fed back to the oscillator to maintain a predetermined phase relationship between the two low frequencies. The phase comparator includes a pair of differentiation circuits, deriving respective pulse trains from these low frequencies, and a flip-flop alternately set and reset by interleaved pulses from the two trains; the integrated output wave of the flip-flop constitutes the feedback voltage controlling the output frequency of the oscillator.