Method of operating an ultrasonic piezoelectric transducer and circuit arrangement for performing the method

摘要

An ultrasonic piezoelectric transducer is alternatingly operated in a transmitting mode and in a receiving mode. In the transmitting mode an electrical excitation signal is applied between one or more common electrodes and one or more transmission electrodes, and in the receiving mode an electrical reception signal is collected between the one or more common electrodes and one or more reception electrodes. Moreover, in the receiving mode one or more electrodes which are not used as reception electrodes are connected via a low impedance connection with the one or more common electrodes which has the effect that in the receiving mode the resonance frequencies of the piezoelectric transducer are shifted to lower values so that with the same operating frequency the piezolectric transducer is in series resonance in the transmitting mode and in parallel resonance in the receiving mode. In this way, the piezoelectric transducer operates under optimum conditions with perfect frequency matching both for transmission and for reception. <IMAGE>