The effects of bandpass limiters on nphase tracking systems
Abstract
The combination of a bandpass limiter and an nth power tracking loop is considered. Performance of the combination does not depend on the form of the nonlinear function used to create the nth harmonic signal as long as some energy in that zone is produced. The order in which the limiter and nth power nonlinearity occur is unimportant so that the results apply equally well to the nphase Costas type of implementations of the nth power loops. Closed form expressions for the signal suppression factors are obtained. Coherent and noncoherent SNR's out of the nth powerlimiter combination can be expressed in terms of two of these suppression factors. The loop SNR of an nth powerlimited phase locked loop is estimated by simply calculating the suppression factors for nth and 2nth power loops. Finally, nth power phase locked loops without limiters are compared with similar loops with limiters; the limiter can actually enhance output SNR at moderate to large input SNR.
 Publication:

IEEE Transactions on Communications
 Pub Date:
 June 1977
 Bibcode:
 1977ITCom..25..569B
 Keywords:

 Bandpass Filters;
 Harmonic Generations;
 Limiter Circuits;
 Phase Locked Systems;
 Signal To Noise Ratios;
 Tracking Filters;
 Mathematical Models;
 Nonlinear Systems;
 Performance Prediction;
 Signal Detection;
 Signal Mixing;
 Signal Processing;
 Transmission Efficiency;
 Electronics and Electrical Engineering