DEVELOPMENT OF 6.4 KBPS ELCELP SPEECH CODEC CHIP

We will introduce in this paper a newly developed codec chip DSP (Digi tal Signal Processor) mu PD77018, which will provide a high-quality sp eech transmission with a lower bit rate. As a speech coding method, th is chip employs the ELCELP (Extended Learned Code Excited Linear Predi ction). This method is an NEC proprietary based on the M-LCELP (Multi- Mode Learned Code Excited Linear Prediction), which was submitted and best honored in the half-rate speech codec standard contest held at th e North American TIA convention. As a channel coding method, we use th e method that was also given the highest evaluation in the contest. Th e codec chip is realized with the NEC-made single chip with 16 bit fix ed decimal point DSP mu PD77018. This chip allows the selection of thr ee operation modes: ELCELP+FEC mode, ELCELP mode, and FEC mode. Input/ output operation uses a serial interface for the speech signal, and us es the host interface for speech coding information and channel coding information.