Ultrasonic distance measure

摘要

An ultrasonic distance measure includes: transmitting and receiving ultrasonic transducers with changeable resonant/resonance frequencies; a driving section generating a frequency-modulated drive signal to drive the transducer and transmit an ultrasonic wave; a transmitting control voltage generating section for generating a control voltage to change the resonant/resonance frequency of The transducer and applying it to the transducer in transmitting the ultrasonic wave; a receiving control voltage generating section for generating a control voltage to change the resonant/resonance frequency of the transducer and applying it to the transducer when a controllable amount of time delay has passed since The drive signal was generated; and a receiving section for sensing the intensity of a signal received as the ultrasonic wave at the transducer.