Patent ID: 7908306

Claim:
A method comprising: (a) storing a plurality of independent sets of filter coefficients in a memory, wherein each set of filter coefficients defines a different polyphase filter function, wherein each of the different polyphase filter functions would result in at least some modifying of a signal if the signal were filtered in accordance with the polyphase filter function, and wherein each of the different polyphase filter functions would result in modifying of a signal in a different manner than the other polyphase filter functions; (b) storing a value in a filter selection register; (c) selecting a single one of the independent sets of filter coefficients based on the value stored in the filter selection register; (d) receiving an audio input signal including a plurality of samples; (e) estimating a sample rate of the audio input signal; (f) interpolating the single one selected set of filter coefficients, in dependence on the estimated sample rate of the audio input signal, to thereby produce interpolated polyphase filter coefficients; and (g) convolving the produced interpolated polyphase filter coefficients with the samples of the audio input signal to produce a filtered audio output signal that differs from the audio input signal regardless of which single one of the sets of filter coefficients is selected; wherein said selecting the single one of the independent sets of filter coefficients at step (c) is performed prior to receiving the audio input signal at step (d), independent of the audio input signal received at step (d), and independent of the filtered audio output signal produced at step (g); and wherein the same single one of the sets of filter coefficients selected at step (c) is used at steps (f) and (g) to produce the filtered audio output signal produced at step (g).