Real-time Implementation Of Qcelp On A Fixed Point Dsp Chip

Abstract

This paper presents a real-time implementation of the QCELP speech coder which has been chosen as digital cellular standard in North America and Korea. A real-time implementation of QCELP algorithm can be realized using 16-bit fixed point digital signal processor. The principle of QCELP algorithm and real-time implementation on fixed point DSP chip are addressed. The paper also discusses the finite word-length effects and considers the methods to reduce the effects through fixed point C simulation. In addition to speech service in CDMA Mobile System, the implementation of data service(be1ow 4.8kbps) by speech coder bypass operation is presented.