System and methods for asynchronous signal interpolation

A method to convert an input signal from a first sample rate to a second sample rate, the method comprising:

• receiving the input signal at the first sample rate, the input signal having one or more input signal values;
• receiving a second sample rate;
• adding a plurality of zero values following each input signal value of the one or more input signal values;
• producing a zero-padded signal based on the input signal by converting each non-zero input signal value of the one or more input signal values to a plurality of non-zero input signal values and replacing one or more of input signal values and the plurality of zero values added following the one or more input signal values with one or more of the plurality of non-zero input signal values;
• and
• producing an output signal by selecting at least one of one or more signal values of the zero-padded signal, the selection of the at least one of the one or more signal values of the zero-padded signal being based on the second sample rate.

A method to convert a signal between asynchronous sample rates, the method comprising:

• receiving an input signal at a first frequency;
• receiving a sample frequency;
• providing the input signal to a zero padding circuit configured to pad the input signal with zeroes to form a zero padded input signal;
• providing the zero padded input signal to a transposed polynomial filter configured to alter the zero padded input signal to produce an altered input signal having each non-zero element of the zero padded input signal transformed into a respective number of non-zero elements of the altered input signal, the respective number of non-zero elements of the altered input signal being equal to the order of the transposed polynomial filter;
• providing the altered input signal to a decimator configured to decimate the altered input signal to produce a decimated altered input signal;
• sampling the decimated altered input signal at the sample frequency;
• and
• providing samples of the decimated altered input signal to an output.