Factor inverse matched filtering

Factor inverse matched filtering (FIMF) and factor inverse filtering (FIF) are signal processing techniques used to obtain desired signal responses. Both are especially useful procedures for ‘‘pulse-compression’’ processing and channel measurements. The theory is developed for a simple channel and known noise power spectral density so that comparison may be made with matched filtering. Expressions for the pulse-compression energy gain, nonflatness loss NFL, and total performance are derived. The NFL is useful in selecting the best among practical pulse-compression modulations, and with FIMF and FIF, has been used extensively since 1974 by the authors and their co-workers in underwater acoustic propagation measurements and ocean acoustic tomography.