Pulse Compression Degradation Due to Open Loop Adaptive Cancellation. Part 3.

摘要

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 (parts I and II, NRL Reports 9107 and 9309) where the signal was assumed to be completely contained within the canceller's processing batch. In this report, 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 report 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 desired signal's presence in the canceller weight calculation. Placement of the pulse compressor before or after the canceller is also considered. It Is shown that if the desired waveform's code length L is less than or equal to the canceller's processing batch width K, 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 trade-off study is necessary. (Author)