DIGITAL PHASE LOCK LOOP CIRCUIT EMPLOYING OSCILLATOR TRIGGERED AT ZERO VOLTAGE CROSSING OF INPUT SIGNAL

摘要

A predetermined number of pulses from the output of a controlled oscillator means is counted. The time duration required to reach this number is compared to the time duration of a predetermined portion of an input signal. On the basis of this comparison the pulse frequency of the oscillator means is varied such that in subsequent time duration comparisons, the time difference is substantially eliminated and the output pulses are in a phase relationship with said input signal.