A novel technique for narrowband/broadband frequency selective limiting in direct sequence-spread spectrum (DS-SS) communications is presented. This technique relies on setting the magnitude response of the received signal Fourier transform to a predetermined function while leaving the phase response unchanged. When the Fourier transform magnitude response of the signal is made constant over the entire signal spectrum, this nonlinear processor will operate as a whitening filter. The processor is particularly attractive in environments where many interferers of different powers coexist in the same frequency band with the desired signal (e.g. wideband HF communications). The only requirement imposed by the processor is that the desired signal must be broadband relative to the interferer(s). This requirement is in general fulfilled by a wide class of communication and radar signals such as DS-SS, hybrid FK/DS-SS, and WB-FM (chirp radar signals).
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