Position locating using digital logic controlled by pulse propagation time intervals

摘要

Apparatus for gauging location of a movable element in relation to an end of an elongated impulse wave energy propagative member employing a sensing transducer adjacent one end of the member to sense first the direct impulse and thereafter the indirect impulse that is reflected from the opposite end. Processing of the sensing transducer responses and sequentially programmed digital measurement of time intervals associated with the duration and time relationship of such responses according to logic equations affords the desired location indication with automatic compensation for ambiently caused variations in shock wave propagation velocity in the member on repeating cycles of operation and with measurement accuracy independent of undue precision requirements in location of the sensing transducer in relation to the adjacent end of the member.