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Proceedings Paper

A robust sinusoidal signal processing method for interferometers
Author(s): Xiang-long Wu; Hui Zhang; Yang-Yu Tseng; Kuang-Chao Fan
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Paper Abstract

Laser interferometers are widely used as a reference for length measurement. Reliable bidirectional optical fringe counting is normally obtained by using two orthogonally sinusoidal signals derived from the two outputs of an interferometer with path difference. These signals are subject to be disturbed by the geometrical errors of the moving target that causes the separation and shift of two interfering light spots on the detector. It results in typical Heydemann errors, including DC drift, amplitude variation and out-of-orthogonality of two sinusoidal signals that will seriously reduce the accuracy of fringe counting. This paper presents a robust sinusoidal signal processing method to correct the distorted waveforms by hardware. A corresponding circuit board has been designed. A linear stage equipped with a laser displacement interferometer and a height gauge equipped with a linear grating interferometer are used as the test beds. Experimental results show that, even with a seriously disturbed input waveform, the output Lissajous circle can always be stabilized after signal correction. This robust method increases the stability and reliability of the sinusoidal signals for data acquisition device to deal with pulse count and phase subdivision.

Paper Details

Date Published: 10 October 2013
PDF: 8 pages
Proc. SPIE 8916, Sixth International Symposium on Precision Mechanical Measurements, 89160N (10 October 2013); doi: 10.1117/12.2035693
Show Author Affiliations
Xiang-long Wu, Hefei Univ. of Technology (China)
Hui Zhang, Hefei Univ. of Technology (China)
Yang-Yu Tseng, National Taiwan Univ. (Taiwan, China)
Kuang-Chao Fan, Hefei Univ. of Technology (China)
National Taiwan Univ. (Taiwan, China)


Published in SPIE Proceedings Vol. 8916:
Sixth International Symposium on Precision Mechanical Measurements
Shenghua Ye; Yetai Fei, Editor(s)

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