Research And Realization On Fixed-point DSP Of G.722.2

The AMR(Adaptive Multirate) speech codec used in GSM and WCDMA system is a multirate narrowband speech codec.For the limited bandwidth,the narrow band AMR speech codec can't satisfy people's needs to high quality speech services. As the wide appolication of VOIP and the 3G handset putting into production, to provide wide band audio service via new grouping phone network which has a better quality than normal long-distance call faces a potential opportunity. The paper details the adaptive multirate wideband speech codec used in third-generation mobile communication systems and wireline wideband service.And the paper focuses on analysis of the source coding technology based on the algebraic code excited linear prediction(ACELP) , researches on the signal processing techonology of upsampling and downsampling, high-band signal processing,the codebook structure of different bit rates which all are specifically used in AMR-WB, briefly analyses the technolory of error concealment and source controlled rate operation which includes the voice activity detector and cormfortable noise generation,and also the paper details the fixed-point C source code recommended by ITU-T. Based on the realization of the adaptive multirate wideband speech codec on fixed-point dsp,the paper researches on the architecture and the key technology of the related dsp which includes direct memory access,multichannel buffer serial port and bootload technology,and also researches on the development enviroment of hardware and software.Based on the above technology, then the paper gives the software architecture of the G.722.2 realized on dsp and designs module of speech interface,system initiating,code and decode. For the high complexity of G.722.2,the paper researches on the key assemble optimization technology of C5416 and details the main ways of programm optimization related to the architecture and instruction set of dsp.Mainly using assemble optimization combined with algorithm-level optimization,we finishes realtime realization the G.722.2 codec.