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Heterodyne laser vibration measuring method based on band-pass sampling

A band-pass sampling, laser vibration measurement technology, applied in measurement devices, measurement of ultrasonic/sonic/infrasonic waves, instruments, etc., can solve the problems of external analog devices and the existence of phase delay, limited vibration measurement accuracy, and large amount of processed data. , to achieve the effects of high vibration signal measurement accuracy, small processing data, and low sampling frequency

Active Publication Date: 2017-04-26
NAT INST OF METROLOGY CHINA +1
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Problems solved by technology

[0005] The purpose of the present invention is to provide a band-based vibrometer based on the current heterodyne laser vibrometer method, which has the shortcomings of high sampling frequency and large amount of processed data or the need for external analog devices, phase delay, and limited vibration measurement accuracy. Heterodyne Laser Vibration Measuring Method Through Sampling

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  • Heterodyne laser vibration measuring method based on band-pass sampling
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  • Heterodyne laser vibration measuring method based on band-pass sampling

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Embodiment Construction

[0055] In order to solve the problems of high sampling frequency required by the existing heterodyne laser vibration measurement method, large amount of collected data and poor real-time performance, or the need for external analog devices, certain phase delay, and limited measurement accuracy, the present invention provides a A heterodyne laser vibrometer method based on band-pass sampling will be described in detail below in conjunction with the accompanying drawings and specific implementation examples.

[0056] refer to figure 1 and figure 2 It is a schematic diagram of an implementation example device of the method of the present invention, and the device mainly includes: a vibrating table 1, a working surface of a vibrating table 2, a heterodyne laser interferometer 3, a vibration isolation table 4, cables 5, and signal processing and display equipment 6. The vibration isolation table 4 is used to fix the heterodyne laser interferometer 3 and is perpendicular to the wo...

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Abstract

The invention discloses a heterodyne laser vibration measuring method based on band-pass sampling. The effective sampling frequency band corresponding to different integers m for avoiding spectrum aliasing of heterodyne laser Doppler signals after acquisition is determined based on the band-pass sampling theorem. Through a band-pass sampling protection bandwidth, enough engineering allowance is ensured, and spectrum aliasing of actual laser Doppler signals is avoided. An optimal sampling frequency automatic selection method based on band-pass sampling is put forward to determine the optimal sampling frequency of heterodyne laser Doppler signals. Finally, acquired heterodyne laser Doppler signals are demodulated based on a phase unwrapping sinusoidal approximation method (PUSAM). The method has the characteristics of low sampling frequency, a small amount of data acquired, good real-time performance and no phase relay on the premise of guaranteeing high-precision vibration measurement effectively. By using the method, the problem that the traditional heterodyne laser vibration measuring method has the disadvantage of high sampling frequency or phase relay for heterodyne laser vibration measurement is solved effectively.

Description

technical field [0001] The invention belongs to the field of laser vibration measurement, and is especially suitable for the vibration signal measurement in the vibration calibration of the heterodyne laser interference absolute method. Background technique [0002] The heterodyne laser vibration measurement method mainly includes the acquisition of the heterodyne laser Doppler signal and the demodulation of the collected laser Doppler signal. The conversion of Doppler signal to digital laser Doppler signal, the purpose of demodulation is to realize the measured vibration measurement through heterodyne laser Doppler signal. For the conventional vibration calibration of the absolute method of heterodyne laser interferometry, the bandwidth of the heterodyne laser Doppler signal is much smaller than the carrier frequency of the heterodyne laser Doppler signal, and the heterodyne laser Doppler signal based on bandpass sampling The required sampling frequency is only related to ...

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Application Information

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IPC IPC(8): G01H9/00
Inventor 蔡晨光杨明刘志华王颖
Owner NAT INST OF METROLOGY CHINA
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