Based On DSP Technology And Multi-spherical Domain Wave Superposition Method Of Acoustical Holography Data Acquisition System Design

As the rapid development of acoustical holography, it is has become an inexorable trend to identify and locate the noise,as well as calculate and visualize sound field based on the local acoustical holography. In current, there are three acoustical holography measuring methods : sound pressure snapshot method, sound pressure scanning method and sound intensity measuring method. However, these methods cannot be widely used in practical engineering for their short comings, such as high cost, excessive calculation and large measurement errors. How to find a fast, accurate and convenient way to measure and calculate the sound field, has become one of the hot issues in the current acoustic holography research.This paper designed and realized a acoustical holography’s signal acquisition and proposing system based on the DSP technology and multi-spherical domain wave superposition method. DSP technology not only fit the requirements of digital signal’s filtering and FFT disposing, but also has advantages like quicker executing speed and higher accuracy when compares with traditional single chip microcomputer. So DSPTMS32028335 was chosen as the central processing unit of the hardware system. According its characteristics, the conditioning circuit and anti-aliasing filter circuit are designed to condition and filter the input signal, so that the input signal could fit technical requirements of the demo-board. On CCS platform, the A/D conversion procedures, sampling data processing and display procedures are compiled based on DSP. In order to make CCS software to run properly, some related files and configuration parameters are also configure. The experimental data can be measure and process by the designed hardware and software systems. Substituting the above acoustic quantities into multi-spherical domain wave superposition method, the distribution of the sound field can be achieved by the Matlab software. To further improve the accuracy of the calculation, L-curve method, filter’s singular value truncating method and Tikhonov regularization method were adopted to optimize the experimental data, and orthocenter method was used to reconfigure the virtual source, the reconstruct result proved the present method was correct.Based on multi-spherical domain wave superposition method and DSP technology, an acoustical holography data collection and disposal system was constructed in this paper. this system can effectively effectively overcome the problem of low reconstruct precision caused by non-conformal between virtual domain and holographic surface. Meanwhile, this method is simple, convenient and accuracy, which can provide a new way of thinking and methods for measuring and calculating of the acoustic holography.