Third-generation Mobile Communications, Adaptive Multi-rate Speech Coding Algorithm

According to the project of adaptive multi-rate speech coding(AMR) being put forward by the third Generation Group of the Mobile Communication,this paper takes the principle of the speech arithmetic as the base,studies the technologies including the Source Controlled Rate,Voice Activity Detector,Comfort noise and the Error Concealment Unit in AMR,discusses its the characteristic of adaptation and analyses its performances particularly. AMR C codes are researched carefully through the modules being divided into and debugged under the TMS320C54X provided by the TI corporation,and optimized in selecting the method of C code embedded assembler codes and simplified in the search codebook combining with the theory of speech coding,which are based on the realization about theory and practice of the optimization of AMR speech coding.