The Amr Vocoder Adaptive Codebook Search Technique And Its Dsp Implementation

There is no doubt that speech communication is the important communication means for human, it is also the most common format in data communication systems. In recent years, the speech communication technologies have developed rapidly. As an important facet of today抯 applications, the paper illustrates two kinds of speech communication system: Mobile speech commnication system and IP speech communication system. For former, we study the details of AMR(Adaptive Multi-rate) algorithm which is a new speech coding algorithm in WCDMA mobile communication systems (3GPP). It includes linear prediction analysis(LPC), voice pitch-extractation, formant-estimation, speech synthesis, etc. The most essential section for the AI~%4iR coding modes is the so-called Code Excited Linear Prediction Coder, hereafter referred to as CELP. We discuss the theory of CELP in detail and the realization of CELP using TMS32OC54X DSP of Texas Instruments (TI). In fact, IP speech communication is a kind of speech-data communication over IP network and its key technique is the IP speech gateway. In this project we make a simple unit to demonstrate it and present the low-level IIO(InputlOutput) drivers on TMS32OC54X DSP We also design a nice software interface on the unit for controllers to configure the parameters.