Ultrasonic distance measuring instrument

Abstract

A non-contact type ultrasonic distance measuring device that includes a micro processor for controlling operation of a transducer that functions as both a sonic transmitter and receiver. Micro processor programming provides a control scheme whereby an operator can program different modes of operation into the instrument by depressing buttons arranged on a rear display panel of the instrument. Mode programming is accomplished in a manner similar to setting a digital watch, with the modes displayed in a display window. The mode programming and component operation provide a gate scheme where gate control is provided through application of gain control through three (3) amplifiers, one of which is a fourth order bandpass filter that is operated by the micro processor to provide a controlled increase in gain or 'Q' as the elapsed time from a transmission becomes greater. The program self-adjusts during operation to sense the distances to close targets and to targets as far away as seventy (70) feet and can provide an accurate identification of a target through clutter as may exist in some instrument applications. Pulsing control is also provided for in the mode programming, whereby, after a single pulse is sent, the instrument will not send a next pulse until the expiration of a set time period.