Further considerations of adaptive canceller and pulse compression interactions

An exact expression for the perturbed range sidelobe level of a compressed pulse that has been preprocessed through an adaptive canceller is derived. This result is a generalization of past research where the signal was assumed to be completely contained within the processing batch of the canceller. Here we allow the signal to extend over an arbitrary number of canceller processing batches. A good approximate expression is also obtained for evaluating the perturbed range sidelobe level. This paper derives the number of independent samples per channel (main and auxiliaries) necessary so that the average adaptive range sidelobe level is within 3 dB of the quiescent range sidelobe level. Furthermore, the same analysis is used to predict the canceller noise power level that is induced by the presence in the canceller weight calculation of a contaminating desired signal. Placement of the pulse compressor before or after the canceller is also considered. It is shown that if the code length L of the desired waveform is less than or equal to the processing batch width K of the canceller, it is desirable to place the pulse compression after the adaptive canceller. If L>K, then the issue is not so clear-cut, and a tradeoff study is necessary.<>