Signal processing system with a digital sample rate converter

A digital sample rate converter circuit comprising:

• a signal generator to generate a discrete-time signal having a sampled frequency of fs0;
• a discrete-time filter comprising an infinite impulse response (IIR) filter and coupled to the signal generator, to receive the discrete-time signal, modify the discrete-time signal in accordance with a low-pass frequency operation, and generate filtered output samples of the IIR filter and auxiliary data, wherein the auxiliary data is distinct from the filtered output signal and comprises a plurality of values within the IIR filter;
• and
• an interpolator to receive the auxiliary data and a subset of the filtered output samples and to determine interpolated sample values temporally between values of the filtered output samples of the IIR filter, wherein the interpolated sample values have a sampling frequency of fs1, wherein fs1 is not equal to fs0, and the values of the output samples of the IIR filter are determined in accordance with a model of a continuous-time filter.

A method of converting a first sample rate of a discrete-time input signal to a second sample rate, the method comprising:

• in a circuit:
• receiving the discrete-time input signal;
• digitally filtering the discrete-time input signal using a filter, which includes an infinite impulse response (IIR) filter, that implements a digital model of a continuous time filter to generate first discrete-time filtered samples having a sampling frequency of fS0 and auxiliary data;
• and
• determining second discrete-time output samples, at a sampling frequency of fS1, from output samples of the IIR filter and the auxiliary data, wherein the auxiliary data is distinct from the output samples of the IIR filter and comprises a plurality of values within the IIR filter, the second discrete-time output samples having values temporally between values of adjacent-in-time values of the first discrete-time filtered samples of a subset of the first discrete-time samples, wherein fS0 does not equal fS1, and the values of the output samples of the IIR filter are determined in accordance with the model of the continuous-time filter.

A method of converting a discrete-time input signal sampled at a frequency fs0 into a discrete-time output signal sampled at a frequency fs1, the method comprising:

• in a circuit:
• receiving the discrete-time input signal;
• filtering the discrete-time input signal using an infinite impulse response (IIR) filter to generate filtered output samples and auxiliary data within the infinite impulse response filter, wherein the auxiliary data is distinct from the filtered output signal and comprises a plurality of values within the IIR filter;
• and
• interpolating the auxiliary data and a subset of the filtered output samples to determine the discrete-time output signal sample values temporally between values of the filtered output samples, wherein the discrete-time output signal sample values have a sampling frequency of fs1, wherein fs1 is not equal to fs0, and the values of the output samples of the IIR filter are determined in accordance with a model of a continuous-time filter.