Some comments on the design and implementation of FIR filterbanks for speech recognition

A program has been written which can generate banks of FIR filters using optimal-equiripple design. The composite responses of these filterbanks are very flat and have a stopband rejection of approximately 60 dB. Also, for purposes of speech recognition, energy estimates from filterbank output are frequently used, and are derived from oversampled, rectified input. A very substantial reduction in the number of calculations can be made if filter outputs are decimated while introducing a tolerable amount of error. This idea has been experimentally evaluated.