A comparison of FIR filter bank design methods with applications to intelligibility enhancement of noise-corrupted speech signals

A formula for the impulse response of a general piecewise-linear-digital filter is developed. A special case of this filter (the trapezoidal filter) produces linear phase FIR filters with good frequency response characteristics when windowed with Hanning (or even rectangular) windows. Bandpass filters designed using this technique result in filter banks with very flat composite frequency responses. In addition, it is found the FIR filters with arbitrary shapes may readily be designed by combining subfilters with trapezoidal shapes. The filter banks and arbitrary shape filters designed by this method have application in techniques used to enhance the intelligibility of noise-corrupted speech signals. The methods presented have considerable potential for the design of both individual filters and filter banks.<>