Phase Non-Linearity Estimation and Reduction of IFM Receiver

This paper reports about phase nonlinearity reduction method in details for a complex multichannel receiver. Phase nonlinearity interrupts the output frequency count coming from unidentified emitters. Thus, decrease of phase nonlinearity of the processed signal is very important. Theoretical phase nonlinearity calculation is explained in this article and estimated. Signal strength and phase rectifications are carried out to maintain phase level smooth over the frequency band. This is done by utilizing numerous gain equalizers by correcting the signal levels over the frequency band. Response of phase nonlinearity brought down to the accepted level by tracking phase of all the passive and active modules within ±5° and all the channels within ±35°. Signal level of all the active components are maintained within PldB so that phase nonlinearity can be kept under control. Signal levels of RF and LO ports of the phase correlators are kept just within the drive level thus phase nonlinearity response becomes less and the receiver can achiev resoled frequency within 3MHzr.m.s.