A phase-locked phase filter for the minitrack system

Abstract

A variable-bandwidth filter has been designed and built to narrow the postdetection bandwidth of the Minitrack satellite tracking system. It is based on phase-lock techniques. Al its narrowest bandwidth, 0.03 cps, the phase peak-to­peak noise deviations are reduced to ± 1.5 percent of a wavelength for a signal strength of -140 dbm coming into the receiver "front ends". The filter introduces no phase shift or time delay regardless of the signal phase rate.