Abstract: A pattern recognition system particularly useful for recognizing speech or handwriting. An input signal is first filtered by a filter bank having two stages where the outputs of the first stage is fed forward to the second stage of a significant number of filters and the output of the second stage is fed back to the first stage of a significant number of the filters. Such feedback enhances the signal-to-noise ratio and resembles the coupling between the different sections of the basilar membrane of the cochlear. The output of the filter bank is a two-dimensional frequency-time representation of the original signal. A second set of filters which takes as input two-dimensional signals, detects the presence of elementary tonotopic features such as the onset, rise, fall and frequency of any significant tones in a speech signal. A third set of filters detects any contrasts in the elementary features at various levels of resolution.