Effect of phase modulator on the performance in a delayed modified heterodyne lock loop

This paper presents a novel method of reducing the deleterious effect of delay introduced by a narrowband IF filter in the loop. The governing system equation of the loop in presence of delay has been derived and the presence of third harmonic component at the output is reported. An attempt has been made to calculate the loop noise bandwidth of the delayed system and the methods to reduce the noise bandwidth has been reported. Theoretical analyses coupled with experimental findings are in good agreement.