Implementing Circular Buffers With Bit-Reversed Addressing

Delay lines are used in many DSP applications. Delay lines provide a buffer of the last N samples of data for a filter or other algorithm. While delay lines can be implemented as linear or circular buffers, buffers of the circular variety are often preferred due to their relative simplicity. Texas Instruments' (TI) TMS320 family of DSPs can manipulate circular buffer pointers without penalty to code size or execution time through their bit-reversed addressing capabilities. Through consistent pointer manipulations, these buffers can be used anywhere traditional circular buffers are used. This application note describes: - How linear and circular buffers handle data movement in a delay line. - The properties and limitations of circular buffers. - How to implement circular buffers with bit-reversed addressing. - Three methods, with step-by-step examples, for handling pointer manipulations.