A NEW SYSTEM FOR PRIMARY INTERFEROMETRIC CALIBRATION OF VIBRATION TRANSDUCERS AT LOW FREQUENCIES

摘要

This paper presents a primary interferometric calibration system that was developed in the Vibration Laboratory at INMETRO for the calibration of vibration transducers and measuring instruments at low frequencies. This system is based on a long-stroke air bearing shaker, and on a data acquisition board. It has been used for calibration of accelerometers and servo-accelerometers within the frequency range from 0,4 Hz to 160 Hz. Optionally, the system can be adapted to calibrate laser vibrometers for their further use as comparison reference transducers. Fully automated calibrations are carried out in compliance with the international standard ISO 16063-11 employing the fringe counting method. Some experimental results obtained with this system will be presented herein.