Improving the performance of composite matched filters

Abstract

A composite matched filter (CMF) bank requires fewer filters than a conventional matched filter bank. Indeed, the reduction is logarithmic. When the CMF output can take on either a logic one or a logic zero, we demonstrate that the bipolar CMF with an output threshold of zero many times outperforms the binary CMF where thresholding is normally performed halfway between zero and logic one. 1 For equally likely orthogonal library elements embedded in white Gaussian noise, the bipolar CMF is shown to yield minimum probability of error. A further advantage of the bipolar CMF is that the detection performance is invariant with respect to multiplication of the input by a positive constant. For optical implementation, a disadvantage of bipolar over the binary CMF is the design requirement of bipolar output encoding.