DIGITAL FREQUENCY COMPARATOR

摘要

A digital frequency comparator circuit whose output is the frequency difference between two input signals and which consists of two flip-flops triggered by the negative going portion of the input waveform connected in a divide-by-four configuration and where the reset output is energized whenever coincident input signals arrive at the first flip-flop's toggle and reset inputs. The circuit produces an output pulse whenever two consecutive negative going portions of an input waveform arrive at the toggle input without an intervening negative going portion of a second input waveform arriving at the reset input of the first flip-flop.