The Research And Development Of The Embedded Speech System Based On MC68HC12

The embedded speech system based on the microprocessor chip is researched in this thesis. On the contrast of all kinds of the speech coding, especially analysing deeply the G.729, we study out a suit of speech coding optimization scheme of G.729. First, the scheme is emulated and analysed with Delphi programmable language in the Windows operation system. This testifys the validity of coding arithmetic. The mixed coding technology with C and assemble language is adopted in the last segment of thesis, which accomplish and optimize the compress arithmetic of G.729 in the MC68HC12 peocesser platform of MOTOROLA. The chip through the amplifyed speech signal, filter circuit and digital memorizer make up of the integrated embedded speech coding system. The speech coding system is 8KHz in sample frequency, 8Kbit/s in coding velocity and approximately 4MHz in bandwidth. The whole delayed time is 15ms. Its quality of voice in speech can reach the standard of international toll-quality speech coding. The speech coding system can applied in wireless locomotive network, digital multiplexing system and computer telecommunication system.