a plurality of sensors and a digital adaptive tuning filter bank are used in extracting a desired emitted signal embedded in a noisy environment . by monitoring noise statistics of the sensor signals , the digital adaptive tuning filter bank automatically adjusts its upper and lower thresholds to obtain a discovery frequency band . the filter bank is designed by examining the discovery band across the sensors and over a predefined period of time . the method described significantly reduces the possibilities of matching self - noise transients and thus minimizes the false alarm rate in emitted signal recognition .