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Priority to TW093140341ApriorityCriticalpatent/TWI268456B/en
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Publication of TWI268456BpublicationCriticalpatent/TWI268456B/en
Measurement Of Mechanical Vibrations Or Ultrasonic Waves
(AREA)
Abstract
This patent presents a method for measuring high frequency vibration based on a hetrodyne laser interferometry system. In a heterodyne system, an electro-optic modulator is used to split the laser light into a two frequency light source with orthogonal polarization state. Usually the frequency is at least ten times higher than the vibration to be measured. However, as the high frequency measurement is desired, the conventional locking amplifier and phase lock loop cannot be applied. Therefore, a method for computing vibration amplitude based on frequency domain analysis is presented in this patent. The acquired sigani is stored and is processed by fast fourier transform to obtain the spectrum of the signal. It was found that the peak values on the spectrum provides the information of vibration amplitude and is utilized for obtaining vibration amplitude.
TW093140341A2004-12-232004-12-23Signal processing method for a heterodyne laser system
TWI268456B
(en)
Detection of the external acoustic action upon an optical fiber using the interferometer of scattered radiation with the aid of the phase diversity method