A mixed-signal correlator for acoustic transient classification

Correlation computations are widely used in template-based temporal pattern recognition, but are expensive to compute in real time on DSP systems. We have designed and fabricated a low-power chip which uses current-mode analog circuits to compute the correlation between an auditory input signal in the time-frequency domain and a stored binary template. We use a bucket-brigade device (BED) to accumulate partial column sums over time at rates consistent with the auditory-band input. Experimental results of the correlator demonstrate its correct operation over a wide range of operating frequencies