Design Of The Signal Processing Unit For The Interferometric Fiber-Optic Voltage Sensor

Interferometric fiber-optic sensor has lots of virtues, such as high sensitivity, nice linearity and wide dynamic range. It has become an important category of the fiber-optic sensor, possessing kinds of structures and principle. Thereinto, the interferometric fiber-optic voltage sensor, basing on the principle of white light interference, takes much attention recently. The phase detection is the chief task of the signal processing unit for the interferometric fiber-optic voltage sensor. This paper is devoted to the study on the phase detection principally.Firstly, the background of the research is presented in this paper, and the various techniques of the phase detection are analyzed. Thereinto, the direct current phase tracking method, with the virtue to eliminate the signal fading caused by random phase-shift, is very applicable to phase detection of the interferometric fiber-optic voltage sensor.In the next place, it is researched the voltage-measure theory of the interferometric fiber-optic voltage sensor and the theory of phase detection. And the performance guide lines of the detection system are instituted.Then, the signal processing analog circuit system is designed basing on the theory of the direct current phase tracking large-signal detection. A mathematical former is designed and the simulation with the former is made.The transfer function of the system is educed. It is analyzed the condition and the process how the system turns to stability. It is validated the system to be answered for the prospective theoretic design with the results of the corresponding experiment system. Besides, the real time and credibility of the system is ensured.Basing on the realization of the signal processing analog circuit system for the interferometric fiber-optic voltage sensor, it is put forward the phase detection digital circuit system for the interferometric fiber-optic voltage sensorbasing on FPGA in the third part of this paper. The subtracter, the integrator, the band-pass filter and the phase tracking system are turned to the digital systems with VHDL language programming and schematic diagram input. Thereinto, it is studied the measure of how to realize a 32-tap linear phase FIR band-pass Filter using distributed arithmetic in detail. The chief part of FIR filter is multiplication- accumulation part. It is adopted LUT structure basing on the distributed arithmetic principle, which conveys multiplication to checking table, improving the processing speed. Finally, the hardware simulation is made. The result proves this method to be capable and high effective.