Sensitivity correction control of the ultrasonic sensor due to Doppler shift

Authors propose the use of an ultrasonic transducer to achieve a passive safety system for a collision using a corner sensor. However, the sensitivity of the transducer decreases owing to Doppler shift in the case of a travelling car. On the contrary, authors also propose a resonance control method for the transducer using a generalized impedance converter (GIC) circuit. In this study, the resonance control frequency method is used to correct the sensitivity of the transducer. In the sensitivity control, the input impedance control of the GIC circuit is tried using a voltage-controlled resistance. The automatic sensitivity correction control is expected to be realized by a combination of the GIC circuit and frequency-voltage (F/V) converter. As a result, the sensitivity of a Langevin transducer with a GIC circuit as a receiver is slightly improved, compared with that of a retailed transducer. Moreover, the resonance frequency of the transducer can be controlled in the range of about 3 kHz using the GIC circuit and F/V converter.