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14 August 2006 The arctangent approach of digital PGC demodulation for optic interferometric sensors
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The development of the optic interferometric sensors is partly restricted with the demodulation technique. The Phase Generated Carrier (PGC) modulation scheme is a useful demodulation method for interferometric sensors, for it is simple and accurate. At first, the PGC scheme is demodulated by analog demodulation techniques. Its capability is limited by the electronic devices, and not fit to the large-scale sensors application. In the past few years, a number of digital demodulation processing approaches have been investigated. Another arctangent approach based on digital demodulator exhibits more advantages than the traditional Differentiate and Cross Multiply (DCM) approach, which has a small measurement range and rather complex circuit. In this paper, the arctangent approach on the PGC configuration used in the array of optical fiber interferometer are discussed and emulated. The measurement range, operation complexity, quality of operation, noise performance, and applicability are compared among the variant arctangent approaches and the DCM approach. The variant arctangent approaches and the DCM approach will be influenced by differently factors, such as, the intensity of the light source, the shift of visibility of the interference fringes due to the change of the state of polarization in fiber, the phase delay. The dependence on these influences of these approaches is analyzed in detail. Their effects and removal methods are validated through emulation.
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Liwei Wang, Min Zhang, Xianhui Mao, and Yanbiao Liao "The arctangent approach of digital PGC demodulation for optic interferometric sensors", Proc. SPIE 6292, Interferometry XIII: Techniques and Analysis, 62921E (14 August 2006);

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