QNAR AGC systems for adaptive signal detection

In a previous paper we presented an NAR AGC system for regulation of noise power in presence of nonoverlapped signals and we showed its limitation in the case of overlapped signals. In this paper we consider the later case for which it is necessary to secure the NAR property all the time otherwise the receiver output will be attenuated. We show that it is possible to satisfy this condition only in a broad sense and the solution in this case is called a quasi-noise-alone reference (QNAR). We present a possible method to achieve a QNAR estimation of the noise power and show by computer simulation the important improvements in the performances of receivers using QNAR AGC circuits in detection systems.