32kbs ADPCM/PCM transcoder using TI-320 DSP microprocessor

The CCITT has recently proposed a Draft Recommendation for a tandemable 64 kbps PCM to 32 kbps ADPCM transcoder algorithm [1],[2]. This paper presents a real-time hardware and software realization of the algorithm based on a single TI TMS 32010 each for the encoder and decoder. Objective and subjective results indicate that our changes in the adaptive quantizer and prediction filter, which make this single µP chip realization possible, do not degrade system performance relative to the CCITT algorithm.