Distance measuring device

摘要

A distance measuring device transmits a continuous alternating wave from a wave source to a target which reflects it back toward the device. The wave source is activated until such time that a detector associated with the device senses the beginning of the reflected wave at which time the wave source is deactivated. The wave source is deactivated during the time that the reflected wave is sensed by the detector and upon the sensing of the end of the reflected wave, the wave source is again activated. The frequency at which the wave source is alternately activated and deactivated is a measure of the distance between the measuring device and the target.