| Laser Doppler velocimetry is a kind of using laser Doppler Effect to measure the speed of the instrument. With the advantages of very high accuracy, speed real-time measurement, measuring wide speed range, high spatial resolution, no subject to bad environmental restrictions and so on. It can widely used in multiple areas of speed measurement. When measuring the solid velocity, the surface of the moving object is not contacted with the characteristic of the moving object. So there is no slippage and friction when measuring solid velocity, and the measuring accuracy is high. It can replace the traditional speed measurement methods in steel rolling and other industrial production. However, the requirement of Laser Doppler velocimetry in the structure and signal processing methods are very high,The rate and accuracy of the results have yet to be improved.Firstly, this paper introduces the development course of Doppler velocity measurement technology and the research status and the significance of the research on solid state Doppler velocity measurement technology at home and abroad. Through the analysis of the principle of Doppler velocity measurement technology, we can build the Doppler velocity measurement system. Mainly is the optical path selection, optical element selection and signal processing circuit design. Through the analysis of fringe pattern, the signal is filtered and amplified, and the signal time domain information is transformed to the frequency domain information by FFT transform. Reduce the noise of signal by the autocorrelation and other processing, and the accuracy of the signal processing result is optimized by the spectrum thinning and the frequency spectrum correction.Finally, the Doppler signal is constructed by Matlab, and the signal processing method is simulated and verified. By building the experimental platform, we get the actual Doppler signal. We get the result that the error can be controlled within 2% bying signal processing of actual Doppler signal. |
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