Performance Degradation of MTI Circuits Due to Amplitude Limiting

Abstract

Further, we assume the signals are narrow band, i.e., phase variations {0X(t)} are slowly varying with respect to carrier frequency f,; then [2, p. 34] =c2 T/2 Abstract The loss in output signal-to-noise ratio (SNR) due to amplitude limiting is obtained for a radar circuit consisting of a bandpass limiter, coherent demodulator, matched filter, and moving-target-indicator (MTI) filter. The circuit is used in scanning MTI radars. The tandem connection of the limiter and coherent demodulator is a model for the saturation of the intermediate-frequency (IF) demodulator of an MTI radar. Results on special functions are used to obtain simple formulas for the loss in output SNR relative to a linear IF demodulator when the input SNR is less than -15 dB and the number of hits per 3-dB beamwidth exceeds 15. CORRESPONDENCE