Multi-channel Acquisition And Processing System For Phase Mesurements

Phase information is one of AC signals three elements, with the development of science and technology, the phase measurement technology's application penetrated into many domains and departments, and more and more high-accuracy requirements. In underwater acoustic areas, it is very important to measurement the phase uniformity of the same frequency signals between different channels, phase uniformity direct influence following signal processing result.In this thesis, the author uses the DSP and FPGA chip as four-channel data acquisition and signals processing electric circuit, and applies it in the acoustic signal phase measurement. Base on thorough comparative analysis home and abroad variety of phase measurement methods, the paper selects FFT (Fast Fourier Transform) as the theory of phase measurement methods, through the FFT algorithm extraction signal's fundamental wave parameter, and then the signal's phase angle can be calculated. Inorder to improve this method's effectivenes, the thesis uses MATLAB signal processing tools as FFT theoretical simulation and error analysis, proved that FFT transform can derive more accurate signal phase information. Study on all aspects of the phase measurement system, and finally according to phase-measuring system's work flow, the whole system is divided into signal conditioning modules, data acquisition module, data-processing module, a keyboard and LCD display module.The phase measurement system's each structure cell's functions and implementations were exhaustived analysis in this thesis. As phase measurement research and realizes, TMS320VC5509 and EMP7128 are used as core processing and control unit. The small signal received by Hydrophone, amplification and filtering by signal conditioning circuit, then gathers by ADS7663, which sampling rate was controlled through the small keyboard. The signal was storaged in DSP, and DSP carries on FIR,FFT data computing, measured phase, the result use CPLD control LCD display. The CPLD contrails system's A/D convertion, LCD display, keyboard control, and communicate with DSP.