Creating filters with arbitrary response characteristics for use in hearing and speech research.

Digital filters with conventional lowpass, highpass, bandpass, and band reject frequency response curves are perfectly adequate for many research applications in speech and hearing. However, there are some specialized applications for which these conventional response characteristics are less than ideal. In this paper we describe a simple method for generating digital filters with virtually any amplitude and phase response. The process involves (a) calculating the impulse response of a finite impulse response filter from a text file that specifies the desired magnitude and phase response of the filter, and (b) convolving the impulse response with the input signal. Sample applications of this method are described.