PHASE-LOCKED LOOP

摘要

A loop filter for receiving an input signal indicative of a phase-difference between a reference signal and a signal output by a signal generator and forming a control signal for controlling the signal generator in dependence thereon, the loop filter comprising a plurality of filter components that determine the frequency response of the filter, said filter components being arranged so that a first set of said components determines one or more zeros of the filter's frequency response and a second set of said components determines one or more poles of the filter's frequency response, each of said first and second sets of filter components being independent of the other such that the zero(s) and pole(s) of the filter's frequency response may be selected independently.