Implementation of an adaptive transform decoder for high-quality audio on a 16-bit DSP chip

A real-time stereo digital audio decoder based on one 16-b digital signal processor (DSP) chip, implementing the decoder portion of an audio compression system, is described. The roundoff-sensitive portions of the decoder include pre multiplier and conventional inverse FFT operations, which have been efficiently coded with mixed-precision 16-b by 32-b multiplies with 32-b accumulations. Compared with a 16-b single-precision implementation, a moderate increase in DSP CPU utilization is incurred. Results indicate that the dynamic range of the 16-b DSP decoder is currently within 1 to 3 dB of the limitations imposed by high-quality 16-b A/D and D/A converters