Ultrasound examination apparatus comprising a mosaic of transducers of an electrostrictive material

An ultrasound examination apparatus, comprising at least one transducer for the repeated emission of ultrasonic signals and, for the reception of ultrasonic signals, a mosaic of individual ultrasonic transducers which are made of an electrostrictive material with a nonremanent polarization which is applied to each individual transducer by a corresponding electrode which is connected to a polarization stage, characterized in that it comprises a processing circuit for the echo signals supplied by the individual transducers in which each of the processing channels associated with one or with several individual transducers comprises coupling means (10i) which serve to couple the electrodes to the polarization stage and which enable the application of a polarization voltage to each of the electrodes while inhibiting the transmission of this voltage to the part of the processing channels which is situated behind the coupling means, said polarization stage comprising a single circuit (20) for generating a voltage ramp having a waveform which is approximately the inverse of that of the curve of the attenuation of the ultrasonic signals within the structures examined.