Noise Analysis And Algorithm Amelioration On The Laser Doppler Interferometer Which Adopting The PGC Demodulation

The optoelectronic technology as a new generation high-tech, in the optical communication, the laser, the glimmer integration of machinery, the clean energy and the green lighting engineering and so on numerous aspects has obtained the high speed development. Now, the light will union with other technical and the industrial, can bring more widespread edge discipline and the emerging industry. Laser Doppler interferes technology followed laser's appearance to produce, it is relying on many characteristics, which contain high sensitivity. high space and time resolution. non-contact and so on. is playing the pivotal role in the numerous domains of production activities and living.This topic based on the laser Doppler interferometer which adopting the PGC demodulation, through analysing the production mechanism of various noise in the interferometer, inquires about the influence to the system's sensitivity and signal-to-noise ratio. We have made the improvement to the PGC demodulation algorithm, proposed the micro vibration amplitude absolute value measuring method with suppressing peak-to-peak drifting in PGC demodulation algorithm.and confirmed the improvement effect through the interference path of rays unify the PGC demodulation technology.In chapterâ… . we elaborated the principle of laser Doppler interference effect, the laser Doppler technology domestic and foreign development overview as well as the common several kind of interferometer's structure and the characteristic. Meanwhile the main content of this paper is summarized and the innovation are showed.In chapterâ…¡, we elaborated the PGC demodulation technology principle, the phase carrier production as well as the two-circuit balanced survey technology principle, proposed initially the superiority that the dual-channel balanced detection technology could eliminate the light source intensity noise. Then we introduced the common several kinds of signal demodulation technology in the practical application, and pointed out their respective advantages and disadvantages. In chapterâ…¢. based on the laser Doppler interferometer which adopting the dual-channel balanced detection technology, we introduced in detail the production mechanism of various noise in the interferometer as well as the influence to the system's sensitivity. As a result of modulation signal's existence, the partial intensity noise remained down, has had certain influence to system's signal-to-noise ratio. By numerical simulating, we analyze the noise, especially the influence of remnant intensity noise to signal-to-noise ratio of the system, and find the optimal parameters of the system.In chapter IV. based on the interference path unify the PGC demodulation technology, we proposed one kind of ameliorate method. Through improving the algorithm, we can suppress the peak-to-peak value drifting in the PGC demodulation effectively, and gain the micro vibration amplitude absolute value of testing signal. According to the experiment datum, we have obtained that the amplitude of testing signal and the modulating voltage value assumes certain linear relationship. In the experiment, the precision could achieve a nanometer magnitude to measurement the micro vibration amplitude.The innovation of this paper is analytical studying the production mechanism of various noise in the interferometer. By numerical simulating, we find the influence of shot noise and remnant intensity noise to signal-to-noise ratio of the system. We have made the improvement to the traditional PGC demodulation algorithm, through the experimental verification.we can suppress the peak-to-peak value drifting in the PGC demodulation effectively and obtain the vibration amplitude of testing signal.