PRIMARY ACCELERATION MEASUREMENT USING FRINGE COUNTING WITH HETERODYNE INTERFEROMETRY |
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| Thomas Bruns, Frank Blume, Henrik Volkers |
- Abstract:
- The application of heterodyne interferometry with direct access to the frequency modulated signal was deemed unfeasible for low frequency vibration measurement, because of the trade-off between a carrier frequency and modulation bandwidth in the MHz range calling for high sampling rates on the one hand, and the low vibration frequency calling for long measuring times on the other hand. Data acquisition systems with the necessary amount of sample memory are expensive and the CPU time needed for the appropriate data processing becomes prohibitive at very low vibration frequencies.
PTB recently developed a new method related to the classic homodyne fringe counting, which reduces the sampling rates for the interferometer signal to ranges related to the spectral contents of the vibration motion.
The new method of heterodyne fringe counting is capable of magnitude and phase response measurements. The contribution describes the methodology and discusses some of its distinctive features and possible pitfalls. - Keywords:
- heterodyne laser interferometry, primary accelerometer calibration, fringe counting
- Download:
- IMEKO-TC22-2014-004.pdf
- DOI:
- -
- Event details
- IMEKO TC:
- TC22
- Event name:
- TC22 Conference 2014
- Title:
3rd Conference on Vibration Measurement (together with 22nd TC3 Conference on the Measurement of Force, Mass and Torque and 12th TC5 Conference on the Measurement of Hardness)
- Place:
- Cape Town, SOUTH AFRICA
- Time:
- 03 February 2014 - 06 February 2014