A gammatone filter is a linear filter described by an impulse response that is the product of a gamma distribution and sinusoidal tone. It is a widely used model of auditory filters in the auditory system. A gammatone response was originally proposed in 1972 as a description of revcor functions measured in the cochlear nucleus of cats. The gammatone impulse response is given by where (in Hz) is the center frequency, (in radians) is the phase of the carrier, is the amplitude, is the filter's order, (in Hz) is the filter's bandwidth,and (in seconds) is time.