Resonant frequencies of the pressure sensors are measured with the famous Polytec MSA-500. Polytec MSA-500 used a Scanning laser-Doppler vibrometry allows non-contact measurements in real time for the characterization of out-of-plane vibrational behavior and for determining the vibration velocity and displacement at any sample point. Unique features include the ability to acquire data with picometer displacement resolution, to capture frequency response up to 24 MHz, and to analyze non-ideal or non-linear systems.
The laser-Doppler vibrometer is a precision optical transducer for determining the vibration velocity and displacement at a measurement position. It works by sensing the frequency shift of back scattered light from a moving surface. The object scatters or reflects light from the laser beam and the Doppler frequency shift is used to measure the component of velocity which lies along the axis of the laser beam.