Design And Implementation Of Directional Speaker Based On DSP Chip

Traditional analog circuit has limited the implementation of the algorithm for directional speaker and affected the performance. Aimed at the implementation of directional speaker based on DSP chip, this thesis studies the design and implementation of directional speaker based on TMS320VC33 chip. Theoretical deduction, computer simulation, system design and testing experiment are systematically conducted.The main interrelated researches can be highlighted as follows.(1)An adaptive method for amplitude control has been proposed. Being different from dynamic carrier, this method overcomes some shortages, for example, the real-time characteristic of dynamic carrier is bad, the computing load is very large, the realization in practice is not easy. This method has already declared the nation invention patents.(2)Three preprocessing methods, DSB modulation without compensation, DSB modulation with compensation and SSB modulation without compensation proposed by the predecessors in order to improve the sound quality of directional speaker are deducted and simulated. Comparative analysis for the characteristics and applications of the three methods are also conducted.(3) Hardware system based on TMS320VC33 for the directional speaker including TMS320VC33 signal processing main board,data acquisition daughter board,input low-pass filter,output band-pass filter,power amplifier and array of ultrasonic transducers is designed,(4)The programming method for TMS320VC33 is mastered. Algorithm for the preprocessing method of DSB modulation with compensation is implemented on TMS320VC33 with the idea of modularized programming and hybrid programming between c and assembly language. -The flexibility of programming makes the debugging of directional speaker simple and convenient. These researches verify the theory of directional speaker and expand the realization method for directional speaker. They have important reference value for the design and implementation of directional speaker.