Phase locked loop with oscillator blocking for improved acquisition time

Abstract

Rapid lock or synchronization between a reference oscillator and a voltage controlled oscillator in a phase locked loop circuit is achieved by a synchronizing circuit. The synchronizing circuit senses the magnitude of the ramp signal produced by the phase locked loop circuit, and produces a blocking signal when the ramp signal exceeds a predetermined level. This blocking signal is applied to one of the oscillators to block that one oscillator pulse during the blocking signal, thus moving the two oscillator signals closer together more quickly, and thus providing lock or synchronization more rapidly.