MEASUREMENT OF TIME DELAY CAUSED BY MIXER AND LOWPASS FILTER IN HETERODYNE INTERFEROMETER

摘要

Phase response is a key performance parameter of vibration transducers, which is usually measured by the primary calibration. The typical primary calibration method used analog mixer and lowpass filter to modulate heterodyne laser interferometer signal. There is some time delay caused by the analog devices, which will introduce some phase delay for the measurement of phase response of transducers. This paper proposed a novel time delay measurement method of the analog devices based on high definition oscilloscope (HDO) and phase unwrapping sine approximation method (PUSAM).