Research And Implementation Of Miniature Audio Directional Loudspeaker Signal Processing Method

Micro audio directional loudspeaker is kind of new type of audio device. Based on ordinary directional speaker and MEMS (Micro Electro Mechanical System) technology, it not only can make use of the non-linearity property of the air to generate directional audible sound but also has incredible size which is suitable for portable device.The main research contents of the thesis are as follows:First of all, the research status of directional loudspeaker around the world is analyzed and the principles of parametric acoustic array are also described.Then an algorithm simulation and testing platform based on LABview and PCI1712 data acquisition card is established. Made use of the platform, square-root algorithm,double-side band modulation,single-side band modulation have been simulated and tested. THD (Total harmonic distortion) and directional angle are especially tested for demodulated audible sound of single-side band modulation algorithm.In addition, the hardware design of signal processing system based on TI TMS320C6722 DSP is completed, which contains power supply design, JTAG interface design, the clock and reset circuit design, expansion of AD / DA design and SDRAM / FLASH memory expansion design. Besides, the software programming work on TI TMS320C6722 DSP is finished, including second boot loader setting,FLASH burning and the implementation of single-side band modulation algorithm. The sound pressure level test is also completed.Finally, according to the test result, high directivity is achieved by the micro directional loudspeaker prototype in this thesis.