Digital Sample-Rate Converters

This paper discusses a real-time implementation of a sampling rate conversion technique between two arbitrary chosen sampling rates. In particular, a method to generate fractionally sampled data from discrete-domain (integer) data samples is analyzed and implemented on the Motorola DSP56001 (24-bit digital signal processor). This real-time implementation can be accomplished with a DSP56001 and 5k of data memory. As an example, the conversion from 44.1 kHz (Compact Disc sampling rate) to 48 kHz (Digital Audio Tape sampling rate) is discussed. The assembly code for the main routine and the filtering method to generate interpolated samples are included.