This paper presented signal demodulation scheme of the laser vibration interferometer system using for measurement of low-frequency vibration. Based on principle of phase generated carrier (PGC) modulation and virtual instrument technology, laser vibration signal demodulation on software and hardware platform were established. Taking the PCI6221 multi-function data acquisition device as the core of hardware circuit, real time data acquisition of reference waveform generation and the signal for measurement was realized. Digital PGC algorithm was established by using LabVIEW software workbench, and then vibration signal real time demodulation was realized. The experiment results indicate that the PGC signal demodulation scheme based on virtual instrument technology reduced drift and noise by traditional analog PGC hardware circuit such as analog multiplier and differentiator, enhanced accuracy of signal demodulation, improved system Signal-to-Noise. High accuracy measurement of the low-frequency vibration signals ranging from 10~200Hz comes true, the measuring resolution is better than 0.5nm, and the dynamic range is 110dB.

Date Published: 26 November 2007
PDF: 7 pages
Proc. SPIE 6830, Advanced Sensor Systems and Applications III, 68301X (26 November 2007);

Published in SPIE Proceedings Vol. 6830:
Advanced Sensor Systems and Applications III
Yun-Jiang Rao; Yanbiao Liao; Gang-Ding Peng, Editor(s)