INNOVATIVE DEVELOPMENTS AND INTEGRATION OF SINE-APPROXIMATION AND TIME INTERVAL ANALYSIS METHODS FOR PRIMARY VIBRATION CALIBRATION BY HETERODYNE INTERFEROMETRY |
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| Qiao Sun |
- Abstract:
- In these paper, innovative developments in sine approximation and time interval analysis methods (SAM and TIA) for primary vibration calibration by heterodyne interferometry are described in detail. The frequency demodulation of novel TIA is based on estimation of time intervals between neighbouring peaks and valleys instead of traditional positive or negative zero-crossings of Laser Doppler Interferometer (LDI) signal, while the simplified SAM uses digital reference signal to generate quadrature signals and perform phase demodulation and differentiation to restore time history of velocity. Because of simplified algorithm and low requirements on hardware, these developments lead to a successful integration of SAM and TIA, both efficient and cost effective, for accurate result and reliable comparison in a single measurement, and to a novel implementation of national medium frequency vibration standard (10 Hz to 10 kHz) in National Institute of Metrology (NIM), China. The validity and accuracy of the novel methods is proved by simulation and will be further verified by a bilateral comparison underway.
- Keywords:
- primary vibration calibration, Sine approximation method, time interval analysis method, heterodyne interferometry
- Download:
- PWC-2006-TC22-015u.pdf
- DOI:
- -
- Event details
- Event name:
- XVIII IMEKO World Congress
- Title:
Metrology for a Sustainable Development
- Place:
- Rio de Janeiro, BRAZIL
- Time:
- 17 September 2006 - 22 September 2006