DIGITAL PHASE COMPARATOR

摘要

A high gain digital phase comparator which in digital phase lock loop systems can give a thousandfold reduction in ripple and close-in noise sideband amplitudes. The comparator is of the sample-and-hold type but the normal ramp reference waveform is replaced by a waveform with a very steep rising or falling slope. This slope is sampled and its steepness gives the increased gain of the phase comparator. Additional logic and switching circuits are added to make the comparator frequency-sensitive.