Efficient microprocessor-based tandemable 32 kbit/s ADPCM/PCM transcoder

The CCITT has adopted a Standard for a tandemable 64 kbit/s pulse code modulation (PCM) 32 kbit/s adaptive differential pulse code modulation (ADPCM) transcoder algorithm [1], [2]. This correspondence suggests slight changes in the adaptive quantizer and prediction filter which facilitate microprocessor realization while potentially improving performance. These variations are then incorporated into a real-time hardware and software system based on a single TI TMS 32010 each for the encoder and decoder. Objective and subjective results on the performance of our design are also presented.