The Real Time Processor LDV Signals with an Acoustooptic Light Deflector and a Position Sensitive Device

This paper describes the signal processor by the use of an acoustooptic light deflector for processing of LDV signals in real time and with high speed. The position sensitive device using the lateral photo-effect of a semiconductor is investigated for real time measurement of the displacement of a beam spot with large intensity variation. The frequency response of the processor is 100kHz and the frequency resolution, 5kHz. As the processor is open loop system, it can process LDV signals in wide frequency range and with high speed compared with a conventional frequency tracker. Using the flow around a circular cylinder, it is demonstrated that this signal processor can be used for continuous and discontinuous LDV signals and is a powerful tool for highly instationary flow.