Study Of The Realization For The Adaptive Codebook Search Algorithm Based On FPGA

The speech communication is the important way for humankind.Today,communication network grows fastly.Many kinds of speech system diversify human's life.Speech encoding is the mathematicical process of the speech's signal.It is the necessary approach in numeric speech signal.The bit rate has a high value that used the pure wave encoding.The hybrid encoding improve the wave encoding.Through the mix of wave and parameter encoding,the low bit rate can be realized by abstracting the amount of pitch's information and ensure speech's quality.The algorithm's core is based on ACELP in the standard G723.1,G.729,AMR,G.722.2 and so on.The principle of adaptive codebook search's algorithm is studied in this paper.The search algorithm is simulated correctly by MATLAB.The open loop and closed loop search of adaptice codebook were realized based on FPGA by Quartus II6.0 platform.From up to bottom and module design are used in the process of realization.These way make the hardware and calculatingconsumption decentralized to some modules.For the FPGA's reconfigurable computing,a model based on the turing's machine abstracts the FPGA's reconfigurable computing.A mathematical model about is put forward in this paper.The key problems about speech encoding and decoding can be mapped into this model.For the hardware FPGA,a cost model is used in the scheme's analyse.It can assessment the project exactly.The adaptive codebook search is applied in the newest area of mobile communication.It is one of the key component in the 3G's speech standard,such as AMR.Based on the FPGA is faster than other ways for the realization of the adaptive codebook search.Based on FPGA fully embodies the real time and flexibility.It is valuable for the speech encoding in engineering area.