AUTOMATIC FREQUENCY CONTROL SYSTEM WITH MEMORY CIRCUIT FOR INCREASING CONTROL RANGE

摘要

An automatic frequency control system has a phase comparator for comparing the phases of a sawtooth wave of a reference frequency and the output frequency of an oscillator and a memory circuit for descriminating or detecting the polarity of the phase difference from two kinds of stepped waveforms generated by the phase comparator in response to the polarity of the phase difference and for storing a DC analog potential in response to the detected polarity. The frequency of the oscillator is controlled by this DC analog potential.