ULTRASONIC POSITION SENSOR

摘要

A position sensor (20) for measuring the distance from a first position to a second position. The sensor may include an elastic wave generator (33 and 25), an acoustical path over which the elastic wave passes (27), and a transducer (26) to which the wave passes. A measurement loop includes the acoustical path (27), and has electrical (31 and 32) and optical (33) elements. The electrical elements (130) may compare the phases of the transducer signals from which the change in position between the first and second positions are determined. Alternatively, the measurement loop may comprise a feedback loop to produce oscillations and an output frequency. A frequency counter (30) is included in the feedback loop to measure frequency.