Patent ID: 8438036

Claim:
An apparatus comprising: an input port that receives a digital audio input signal and that outputs a plurality of signals obtained from the digital audio input signal, wherein each signal is sampled at one of a plurality of frequencies; a rate estimator that is coupled to the input port, wherein the rate estimator determines at least one of the frequencies; a sampling rate converter (SRC) coefficient generator that is coupled to the rate estimator, wherein the SRC coefficient generator calculates a plurality of filter coefficients; a digital signal processor (DSP) that is coupled to the SRC coefficient generator and the input port, wherein the DSP performs digital-to-analog conversion filtering for the signal received from the input port and the filter coefficients from the SRC coefficient generator and wherein the DSP includes: a plurality of interpolation filter circuits, wherein each interpolation filter circuit receives at least one of the signals from the input port; a finite impulse response (FIR) filter that receives an output signal from at least one of the interpolation filter circuits and that receives the filter coefficients, wherein the FIR filter has two taps; a zero order hold (ZOH) circuit that is coupled to at least one of the interpolation filters; and a mixer that is coupled to the ZOH circuit and the FIR filter; and interface circuitry that is coupled to the DSP and the input port, wherein the interface circuitry receives an output signal from the DSP.