Digital filtering techniques for an acoustic stimulation system

A method of employing digital filtering techniques on a laboratory computer to generate acoustic stimuli is presented. Filtered noise has broad applications in such areas as auditory neurophysiology, psychophysics and audiometry. The spectral characteristics of the acoustic stimulus are output on-line by the computer. The filter may be either low- or high-pass or may have one or two passbands. Two important considerations in the design of a filter for neural response studies in animals are the stopband requirements less than -80 dB) and the high output rate (up to 50 KHz). A finite impulse response, optimized frequency sampling filter is used to meet the first criterion and a direct memory access output port satisfies the second.