The Effects of Mismatch and Distortion on the Output Signal of a Linear FM Pulse-Compression Filter

摘要

The output functions of the pulse-compression filter which correspond to the matched filter case and the mis matched case are compared. Numerical comparison is made for two pulse-compression systems of particular interest. The primary effect of mismatch is found to be a reduction in signal-to-noise ratio which, in the worst case considered in this report, is less than 10 per cent. Deviations from the idealized rectangular amplitude spectrum and linear group delay of the transmitted signal, which was used in the previous analysis, are considered. These deviations, which are viewed as distortions, are chosen to provide a more realistic representation of the transmitted signal. The output signal thus obtained is expressed as the sum of the original term and a distortion term. An upper bound for the phase difference caused by the distortion term is obtained and is found to be negligibly small, even in the worst case considered. It therefore appears that the equations derived in the previous reports (and which were based on the idealized signal) need not be modified, and that the given procedure for relating the phase and delay measurements to the target parameters remains valid. (Author)