VECTOR VELOCIMETER (DIRECTION INDICATING VELOCIMETER)

摘要

A source of radiation such as a laser directs a substantially monochromatic beam towards a reference surface. An optical grating located near the source, in conjunction with a photodetector, transforms the reflected radiation into an electrical signal. A standard frequency is generated internally of the device and is compared, by suitable circuitry, with the frequency obtained from the reflected radiation. Positive and negative values are obtained for the velocity components from the comparison of these two signals. Additionally, the existence of this internal standard permits the measurement of zero and near-zero velocity.