Two applications of simple non-linear signal processing

This paper describes two different applications of nonlinear signal processing. In both cases, computational simplicity was a major goal and a nonlinear approach significantly increased performance. The two applications (PSK demodulation of a noisy signal from sign-only data, and frequency estimation of a single complex tone) are both of practical importance. It is also hoped that these two examples will encourage designers of real systems to investigate non-linear approaches. Finally, the examples may be of interest to theoreticians since in neither case has a full theoretical analysis been completed.