Velocimeter, signal processing method, and driving system using the same

摘要

A velocimeter includes a light source for irradiating light onto an object to be measured, a light-receiving element for receiving scattered light from the object and outputting a light-receiving signal upon receiving the scattered light, a signal processing circuit for obtaining velocity information of the object to be measured by performing signal processing of the light-receiving signal output from the light- receiving element, a bandpass filter arranged in the signal processing circuit and having a function of passing frequency components near the frequency of the light-receiving signal to be obtained when the object to be measured is in a still state, and a switch arranged in the signal processing circuit to activate the bandpass filter substantially in the signal processing circuit when the moving velocity of the object to be measured is low.