Abstract: An apparatus for the examination of an object by ultrasonic echography, includes an array of n ultrasonic transducers which is associated with a stage for the emission of signals for scanning the object and with a stage for receiving and processing echographic signals retumed to the transducers, by the obstacles encountered in the object scanned. The emission stage is configured for the focusing of m simultaneously emitted ultrasonic beams, by virute of n emission modules, each of which, for example, the i.sup.th emission module, itself contains m signal generators (201a.sub.1, . . . , 201m.sub.1) which are connected in parallel (or a single signal generator followed by m parallel-connected delay circuits), a stage (202i) for combining the m signals thus generated, and an amplifier (203i) for applying the amplified combined signal to the transducer (10i) corresponding to the relevant emission module.

Abstract: For focussing an ultrasound beam delivered by a transducer array on a reflective target in a medium, for instance in organic tissues, the zone including the target is illuminated with an unfocussing acoustic beam. The shapes and position of echo signals delivered by electro-acoustic transducers of a regular array are individually stored; the distribution in time and the shapes of the echo signals for obtaining reversed signals are reversed and the reversed signals are applied to the respective transdcuers of the array.

Abstract: On emission and/or on reception, circuits impose on the signals emitted and/or received, delays in accordance with a random or pseudo-random delay law. On emission, just as on reception, this delay law is superposed on that for focusing and angulation of the signals. On emission, the law is obtained, for example, by causing variation of the instants of triggering of the generators of signals for the excitation of the transducers. On reception, either parallel random delay lines or conditional inversion circuits are included. These circuits permit the breakdown of the coherence of the ultrasonic waves on emission, on reception, or on both simultaneously, may be used in an analogue version, as well as in a digital version.

Abstract: The ultrasonic echograph comprises at least one piezoelectric transducer (10, 13) for the transmission and/or reception of an ultrasonic scanning beam (20). With at least one piezoelectric transducer (10) there is associated a random phase screen (11) which is arranged in the ultrasonic scanning beam (20) and which is displaceable with respect to the axis of this beam. Means are provided for the recording of an echographic line e(t) for each position (.alpha.) of said random phase screen. The major technical effect of the presence of the random phase screen in the ultrasonic beam path is the disturbing of the coherence of the wave traversing the screen.Applications can be found notably in medical ultrasonic echography and non-destructive testing of materials.

Abstract: An ultrasonic echography apparatus which comprises a first processing circuit (100) of a known type for the processing of the ultrasonic echos in order to display an A-type echogram on a display device (103), and a second processing circuit (200) which is connected parallel to the first processing circuit and which consists mainly of an amplifier (210), a group of n parallel connected channels (220a . . . 220n) each of which comprises at least one band-pass filter (221a . . . 221n) and one envelope detector (222a . . .

Abstract: A method for the scanning of non-linearly dispersive objects whereby changes of the energy spectrum of echographic signals can be quantitatively related to parameters of the objects examined, that is to say the ultrasonic attenuation factor .beta. and the exponent r which characterizes the relationship between the non-linear variation of the attenuation and the frequency. To this end, the signals received are split into a number of (n) substantially equally wide, consecutive frequency bands which together cover approximately all frequencies of the signals received. The envelope of the signals in each frequency band is determined and each of the envelopes is multiplied by a correction signal in order to compensate for the diffraction effect. The logarithm of the envelopes thus corrected is determined, after which the following operations are performed by means of the n signals thus obtained:(a) the slope .beta.f.sub.i.sup.r of each of these n signals is determined;(b) this signal .beta.f.sub.i.sup.

Abstract: A device for scanning objects by means of ultrasound echography, comprising at least one ultrasound transducer (10) which is connected to a transmitter stage (20) and to a receiver stage (30) which comprises an amplifier (40), a correction circuit (50) for the correction of the gain as a function of time, and a processing circuit (60) for the processing of the results of the echographic examination. The receiver and processing stage also comprise a circuit (70) which is connected to the output of the assembly formed by the amplifier and the gain correction circuit and which comprises means for determining the instantaneous frequency and the instantaneous energy of the echographic signal, means for weighting the instantaneous frequency with the instantaneous energy, and a diffraction correction circuit (80).