Abstract: A shock wave sensor is disclosed in which a piezoelectric foil is either suspended in a ring or on a backing. Electrodes run from a particular sensitive area on the foil towards the edges and are fracture proof connected to concentric conductors.

Abstract: Ultrasonic inspection apparatus includes a linear array of transmitting transducers and a linear array of receiving transducers providing TTU mode ultrasonic inspection. One to four transmitting transducers may be simultaneously pulsed as a group, and one to four receiving transducers may be simultaneously connected in common in a group by operation of a connection circuit. The connection circuit includes a plurality of multiplexer circuits having their signal inputs connected in common to respective receiving transducers and their address terminals connected to the data output terminals of programmable read only memory devices.

Abstract: Apparatus for determining or measuring the depth of precipitation accumulating on the surface of a pathway, such as an airport runway or the like. The apparatus includes a sensor having electrical transducer means for emitting and sensing ultrasonic energy and having a body of material adapted to be embedded in the pathway with the top surface of the body being substantially flush therewith and exposed to the precipitation, the transducer means being physically coupled to the body. A circuit causes the transducer means to emit pulses of ultrasonic energy which are reflected as a plurality of reflections from the top surface of the body and from the upper surface of an accumulation of precipitation on the top surface of the body and are respectively returned to the transducer means which in response to the reflected pulses produces corresponding electrical signals.

Abstract: Arrangement for the ultrasonic examination of objects by a local immersion technique, comprising:a source of liquid,a pump fed by said source,a coupling head fed with liquid by said pump and capable of directing towards the object to be examined a jet of the said liquid and a beam of ultrasonic waves which is contained in said jet and is coaxial with this jet, said coupling head comprising:(a) a first tranquilization chamber connected to the outlet of said pump,(b) a second cylindrical tranquilization chamber connected to the said first chamber by at least one channel for the passage of the liquid,(c) an ultrasonic transducer capable of emitting a beam of ultrasonic waves by means of an active surface, which is directed towards the object, said active surface being situated in the second chamber, centered on the axis of said second chamber and perpendicular to this axis,(d) a converging system coaxial with the said second chamber, the shape of which results from a calculation for the purpose of reducing or el

Abstract: An improved ultrasound transceiver providing enhanced imaging by selective filtering of the received signal to provide a variable frequency, constant bandwidth filtering of the received echo signals. The transceiver provides a constant bandwidth filtering by upconverting the received signals to a higher incremented frequency, which is thereafter detected. The resulting signals are then displayed wherein the number of false multiple images is reduced, and the signal quality from the deeper tissue discontinuities is enhanced. The resulting signal is thereafter post-processed to provide enhanced information which is used to display structural features.

Abstract: A material is disclosed for use as an adaptation layer in ultrasonic transducer units of the type which have a piezo-ceramic transducer. The material is porous, and the acoustic impedance of the material can be adjusted (in one embodiment, to 12.times.10.sup.6 kg/cm.sup.2 s) by adjusting the porosity of the material. In preferred embodiments, the material is piezo-electric and may have a porosity gradient.

Abstract: Apparatus for determining the depth of precipitation accumulating on the surface of a pathway, such as an airport runway or the like, includes a sensor having electrical transducer means for emitting and sensing ultrasonic energy and having a body of material adapted to be embedded in the pathway with the top surface of the body being substantially flush therewith and exposed to the precipitation, the transducer means being physically coupled to the body. A circuit causes the transducer means to emit pulses of ultrasonic energy, which are reflected as first and second reflections from the top surface of the body and from the upper surface of an accumulation of precipitation on the top surface of the body and are respectively returned to the transducer which, in response to the reflected pulses, produces corresponding first and second electrical signals.

Abstract: A vibration and acoustic wave detecting device employing a piezoelectric element has a construction such that a piezoelectric element comprises a first surface electrode disposed on a first surface of the piezoelectric element and having a first output terminal of the detecting device, a second surface electrode opposite to the first surface thereof, a side electrode disposed to surround a side surface of the detecting device and having portions respectively extending over the first and second surfaces, the three electrodes being disposed separately from each other, and a resistor disposed on the piezoelectric element to extend across the first surface electrode and the side electrode and to be connected therewith electrically, and the piezoelectric element further comprises a conductive member which is attached to the piezoelectric element to be in contact with the second surface electrode and the side electrode and hence to provide electrical connection between both electrodes.

Abstract: Ultrasonic testing device with a test head which includes an electromechanical transducer, especially a piezoelectric oscillator, with an ultrasonic equipment and with a shielded cable which connects the test head to the ultrasonic equipment. The test head has two electrically conducting shields which surround the transducer in cup-fashion. The two shields are connected to the outer conductors of the triple coaxial cable. The outer conductor of the cable is connected to a metal housing of the ultrasonic equipment and is grounded.

Abstract: An ultrasonic piezoelectric transducer and a method for measuring and/or monitoring the thickness of a wear member, in-situ, and the amount of wear that has occurred thereto, is disclosed. The transducer includes a sleeve which is received in a blind bore provided in the wear member, a piezoelectric element positioned within the blind bore, and an aligning spacer means interposed between the end of the sleeve and the piezoelectric element. By the application of appropriate voltage pulses to the piezoelectric element, the wall thickness between the bottom of the blind bore and the inner surface of the wear member can be measured.

Abstract: An ultrasonic probe for the weld inspection of nuclear reactor vessel nozzles is constructed from a plurality of segments interconnected by means of a flexible joint and protected by bumpers of various shapes. The probe is capable of successfully operating in an underwater and radioactive environment under remote control while maintaining a high degree of control over the placement and movement of the included transducer assembly for performing contact type testing. The transducer assembly, which includes an ultrasonic transmitter and receiver, is mounted within an ultrasonic sensor body which permits insertion of the probe within a nozzle of a reactor vessel while maintaining direct surface to surface contact with the nozzle for weld area examination by contact type testing.

Abstract: An ultrasonic transducer comprises a cylindrical housing embedded within a rear bumper of a vehicle and opening backward, a reflecting plate having a parabolic reflecting surface provided within the cylindrical housing along a closed end thereof and facing an open end thereof, and an ultrasonic vibrator provided in an upper wall of the housing at the focus of the reflecting plate for emitting and receiving ultrasonic waves. The ultrasonic transducer transmits ultrasonic waves behind the vehicle and receives ultrasonic waves reflected from an obstacle. The ultrasonic transducer further comprises a projecting member provided on the inner wall of the housing along the open end thereof for dispersing and cancelling the ultrasonic waves entering the housing at angles with respect to the axis of the housing. The projecting member has a smoothly curving cross section having a radius of substantially one fourth to five times the wavelength of the ultrasonic waves emitted by the ultrasonic vibrator.

Abstract: Sound heads (SK1 to SK3) are fixed, distributed peripherally, on the part of the body, e.g. an arm or leg. Each of the sound heads is able to transmit ultrasonic signals along a measuring section (MS1 to MS3) leading to another sound head, which signals are received by the other sound head. The sound heads can consist of angularly arranged sound members (14). In this way, all three sides of a polygon formed by the sound heads are measured, from which measurements the surface area of the polygon can be determined.

Abstract: A method for evaluating echo signals transmitted and received by an ultrasonic transducer in a sensor of a movable mechanical element, such as an arm of an industrial robot, has the steps of receiving and storing the arriving echo signals in chronological sequence in a memory, the chronological sequence of the signal being converted into a corresponding sequence of memory positions, with successive sequences of echo signals of successive transmit pulses being stored in the same sequences of the memory positions. Integration of the echo signals of the successive sequences stored in the memory positions are undertaken such that the local shift of the ultrasonic transducer disposed on the moveable element which occurs between respective transmit pulses is compensated relative to chronologically adjacent pulses and the pulses reflected from a target are more easily identified.

Abstract: Method and apparatus for nondestructive inspection and detection of flaws in a workpiece according to four techniques is disclosed. Elastic waves are thermoelastically or electrodynamically induced in a workpiece by electric current energization of an elastic wave inducing source adapted to be disposed in contact with the workpiece remote from a defect. An acoustic sensor is disposed in elastic wave transmitting contact with the workpiece remote from the source and produces an output signal having an amplitude representative of received elastic waves. The presence of a crack, flaw or defect in the workpiece is detectable as a variation in the amplitude or other characteristics of the acoustic sensor output signal.

Abstract: A mechanism for attaching an ultrasonic head of an ultrasonic microscope to a vibration shaft of a vibrator is disclosed. A first connector half to which an R.F. cable is connected is fixedly arranged to the vibration shaft and a second connector half having the ultrasonic head coupled therewith is detachably attached to the first connector half, so that an exchange of the ultrasonic head can be performed in an easy and swift manner without affecting the position and characteristics of the R.F. cable.

Abstract: A special angle beam probe for ultrasonic testing includes at least one ultrasonic vibrator fastened in a beam probe housing on a wedge-shaped support body which may be formed of Plexiglass, using damping means. The ultrasonic beam of the vibrator strikes the surface of the test piece at an incidence angle other than 0.degree., as measured from a perpendicular at the surface of the test piece at the point where the beam strikes. The ultrasonic beam furthermore strikes the test piece surface at an oblique angle between 0.degree. and 360.degree. subtended between a principal beam probe axis and the beam, as seen in the direction perpendicular to the beam probe from above. The novelty of the invention is that the special angle beam probe includes a multiplicity of prefabricated beam probe subassemblies. The ultrasonic vibrator of each subassembly is fastened with a predetermined incidence angle within a first beam probe housing.

Abstract: An ultrasonic probe for use in ultrasonic imaging systems includes an array of piezoelectric transducer elements. The array is backed by a rear member of an energy absorbing material composed of a mixture of urethane rubber and microballoons. The rear member has a Shore-A hardness greater than 85, an ultrasonic absorption coefficient greater than 1.5 dB/mm at the frequency of energy generated by the array and an acoustic impedance in the range between 1.0.times.10.sup.5 g/cm.sup.2 sec and 3.0.times.10.sup.5 g/cm.sup.2 sec. Alternatively, the rear member is composed of a mixture of thermosetting resin, microballoons and solid particles. Preferably, a thermosetting resin layer is provided between the array and the rear member to ensure against disconnection of wire leads from transducer electrodes.

Abstract: A system for driving an ultrasonic transducer for use in ultrasound imaging of a target includes a charging voltage generator, a first impedance for coupling the charging voltage generator to a terminal of the transducer to permit the transducer to charge sufficiently slowly from the charging voltage source so that charging strain is not coupled from the transducer to the target, and a switch coupled to the transducer. Closing of the switch permits the transducer to discharge sufficiently rapidly that discharging strain is coupled from the transducer to the target. A system for processing return echoes includes a return echo-related signal processor. The return echoes impinge upon, and cause voltage signal related to the return echoes to appear across the terminals of, the transducer.

Abstract: In an ultrasonic imaging apparatus, the pulser applies drive pulses to the transducer element. Depending upon the transducer characteristics and the scanning mode of the ultrasonic beams, the pulser is required to apply proper drive voltage to a given transducer element. The voltage selector switch is provided to select the desirable drive voltage from the power source. Further, the transistor is provided to adjust the selected drive voltage so as to obtain the most preferable drive voltage for the transducer element.

Abstract: A monitoring system utilizing an ultrasonic transducer wherein the power level of the transducer operating signals is raised while maintaining the gain about unity for permitting the use of relatively longer signal paths between a signal generator and the transducer.

Abstract: A precision acoustic source that is capable of producing acoustic radiation having peak and average power levels that are independently and simultaneously adjustable. The apparatus comprises an acoustic transducer and drive means for producing a drive signal comprising a series of drive pulses to the transducer, such that the transducer produces acoustic radiation having selected peak and average power levels. The drive means comprises means for establishing a series of fixed-length clock cycles, means for generating a series of trigger signals, pulse generating means responsive to each trigger signal to produce a selected number of standard pulses, an amplifier for generating a drive pulse in response to each standard pulse. The amplifier adjusts the amplitude of each drive pulse such that the peak power of the acoustic radiation is equal to the selected peak power level. Each trigger signal occurs either R or S clock cycles after the preceding trigger signal, R and S being positive integers.

Abstract: A system for testing the fabrication of objects utilizes echo-sounding techniques. A transmit transducer and a receive transducer which provide a conversion between electric and sonic energies are acoustically coupled to the object under test. A single cable connects the transducers to a single processor which generates, receives and analyzes the signals utilized in the test process. A coupling circuit connects one end of the single cable to the two transducers and isolates a transmitted signal from a received signal so as to permit their communication by the single cable. Within the coupling circuit, a transmitted signal is communicated by a set of serially connected diodes wherein the forward voltage drop is much less than the voltage of the transmitted signal, but greater than the voltage of an incoming signal such as a reverberation of the transmitted signal or a received echo signal.

Abstract: An improved transceiver for use in ultrasonic echo-ranging systems is disclosed together with a system for its use. The transceiver comprises a capacitor to store power received from a central location during an inactive mode, and switching means to disconnect the capacitor from the power supply during the active mode. The capacitor is used both to supply power to an electrostatic transducer to generate an ultrasonic pulse and also to provide a noise free bias voltage to the transducer to enable it to receive the reflected pulse. An amplifier is provided as part of the transceiver so that long transmission lines between transceiver and controller are possible without undue noise. The power supply line can also be used as the signal transmission line and can be provided in a simple two-wire shielded cable, the other wire being used for logic level control signal transmission, thus allowing simplified multiplexing of a plurality of transceivers.

Abstract: A method and an apparatus for generating short ultrasonic echo pulses by means of an ultrasonic transducer (2) utilizes a shift register (6) for storing a signal for excitation of said ultrasonic transducer. The stored signal is a weighted least squares filter signal to the transducer proper and is supplied to said transducer via a digital-to-analogue converter (7). Repeated adjustment of the stored signal can be effected by supplying, via an analogue-to-digital converter (11), the echo pulse signals from the ultrasonic transducer to a logic unit (12) for analysis.

Abstract: An ultrasound visualization system, and certain aspects of the electronics that are incorporated therein. A scan conversion system which includes means for converting the ultrasound scan signal into a stream of single bit digital data in which each bit is indicative of the relative amplitude of the ultrasound scan signal as compared to the amplitude indicated by previously converted digital data. The single bit digital data is inputted and stored alternately into two full screen buffers. As the data is read into one of the two full screen buffers, the stored data in the other buffer is being simultaneously converted into an analog television video signal. The digital to analog conversion is accomplished by varying an analog television video signal in response to the relative amplitude indicated by each bit in comparison with the amplitude indicated by previously converted digital data.

Abstract: This invention relates to ultrasonic test instruments using wide-band test probes of different nominal frequencies fo and discloses an arrangement wherein each wide-band test probe of different nominal frequency fo is coupled in circuit with a receiving amplifier having a frequency response V(f). The frequency response of the receiving amplifier is so selected that the product H(f) comprising the spectral distribution S(f) of the transmitter and the frequency response V(f) of the receiving amplifier is substantially constant approximately up the the nominal frequency fo of the test probe and has its maximum value in that range. For the transmitters conventionally used in ultrasonic test instruments, in which the transmission pulse is generated by a capacitor discharge, the frequency response V(f) of the receiving amplifier should have a linear rise of 6 dB/octave up to approximately the frequency fo.

Abstract: A probe for obtaining information about a fluid comprising an electrically-shielded transducer having a lens for focusing energy waves, the transducer being attached to a cable and mounted in a protective sheath supported by a rod, whereby the transducer can be immersed in the fluid and moved around therein to take readings at various locations.

Abstract: The wide dynamic range ultrasound receiver utilizes a multi-stage logarithmic amplifier in order to logarithmically amplify a returned echo signal. The output of the returned echo signal from the logarithmic amplifier is simply added to a saw-tooth wave Time Gain Control (TGC) signal. Thus, the wide dynamic range of the returned echo signals is simply converted into a video display.

Abstract: Ultrasonic transducers, of an electrical capacitor formed of a counter-elrode and a synthetic material film lying thereon, held by a clamping ring and metallized on one side, are used amongst other things for running time measurements in flow field examinations in wind tunnels. It is in that case important to disturb the flow as little as possible by the spatial dimensions of the ultrasonic transducer and by the necessary mountings and current feeds. For the solution of the problem, it is proposed to fasten the counter-electrode (2) and the clamping ring (3) holding the synthetic material film (5) electrically insulated therefrom on a conductor plate (6) and electrically conductively to connect each with a respective conductor track portion (7, 8 or 7, 10, 8, 9).

Abstract: A novel method for imaging body tissues is disclosed wherein an ultrasonic pulse having a radially asymmetric side-lobe pattern surrounding a central focal lobe is generated. A receiver for receiving echoes of this pulse is provided which exhibits a sensitivity to echoes from the aforementioned side-lobe pattern which is relatively decreased by comparison to its sensitivity to echoes from the central focal lobe. In the preferred embodiment, square transducers which are rotated with respect to the focal axis by about 45.degree. are used to practice the disclosed method.

Abstract: Leaks or thin spots in containers, as well as mechanical faults, e.g. worn bearings, are detected by an ultrasonic energy indicator that includes a modulator that heterodynes ultrasonic signals received by a transducer and creates an audio signal related thereto. The transducer includes a series arrangement of piezoelectric crystals feeding a field-effect transistor amplifier and the modulator operates in an amplitude modulation, suppressed-carrier mode which can be stabilized by a feedback loop. For indicating the presence of the audio signal, either headphones or a meter or both are employed. When leaks in a container are being detected, an ultrasonic generator is used which varies its output frequency slowly over a band of frequencies. The leak detection technique can be improved by applying a thin layer of a liquid to the container surface so that pressure introduced into the container causes the formation and bursting of bubbles in the liquid that results in the production of ultrasonic energy.

Abstract: Ultrasonic flaw-detection method for austenitic alloy steel longitudinally welded pipe or tubing adopts shear wave angle method using a broad-band high-damping and non-resonance type transducer.

Abstract: An improved transceiver for use in ultrasonic echo-ranging systems is disclosed together with a system for its use. The transceiver comprises a capacitor to store power received from a central location during an inactive mode, and switching means to disconnect the capacitor from the power supply during the active mode. The capacitor is used both to supply power to an electrostatic transducer to generate an ultrasonic pulse and also to provide a noise free bias voltage to the transducer to enable it to receive the reflected pulse. An amplifier is provided as part of the transceiver so that long transmission lines between transceiver and controller are possible without undue noise. The power supply line can also be used as the signal transmission line and can be provided in a simple two-wire shielded cable, the other wire being used for logic level control signal transmission, thus allowing simplified multiplexing of a plurality of transceivers.

Abstract: A pulse-echo device with an improved signal-to-noise ratio, in which sound-transmitting material adjacent to the device is coated with a sound-absorbing layer, the layer being sound-impedance matched to the material so that much of the spurious ultrasonic energy travelling in the material passes through the layer-material interface into the layer where it dissipates instead of remaining in the material and reflecting back to the device.

Abstract: A pressure coupled ultrasonic waveguide is provided to which one end may be attached a transducer and at the other end a high temperature material for continuous ultrasonic testing of the material. The ultrasonic signal is coupled from the waveguide into the material through a thin, dry copper foil.

Abstract: An ultrasonic test probe comprises a transducer and an electrical circuit, particularly means for generating the high voltage transmit pulse to the transducer, all disposed within the probe housing. The high voltage transmit pulse is produced by current flow through an electrical inductor. Other circuit components are also arranged within the probe housing.

Abstract: A probe is disclosed for the nondestructive inspection of the interior walls of cylindrical recesses, comprising an elongated shaft having an ultrasonic transducer mounted thereon a predetermined distance from the longitudinal axis of the shaft and oriented for directing the axis of radiation of ultrasonic energy emanating from the transducer outwardly in a plane perpendicular to the longitudinal axis of the shaft. In another embodiment, the probe comprises a shaft having a lateral extension whereon a first ultrasonic transducer is mounted at a predetermined distance from the longitudinal axis of the shaft and is oriented for directing the axis of radiation of ultrasonic energy emanating therefrom parallel to a line formed by the intersection of planes perpendicular to the longitudinal axes of the shaft and lateral extension.

Abstract: In an ultrasonic wave transmitter for generating spatially incoherent ultrasonic radiation, which transmitter includes a source of ultrasonic acoustic radiation, there are provided a member holding a fluid medium in a region exposed to the acoustic radiation, a plurality of particles immersed in the medium and having a diameter of the order of magnitude of the wavelength of the acoustic radiation and an acoustic radiation impedance different from that of the medium, and a device for subjecting the particles to an irregular movement in the medium and within the region.

Abstract: A pit depth gauge for use as an accessory to an underwater ultrasonic probe omprises two resiliently biased, freely flooded telescoping members a first of which has a first end wall adapted to ride on a surface to be inspected and a second of which has a second end wall adapted to be connected to the probe with the probe transducer in registration with an acoustic energy port. A stylus is fixed to the second member for axial movement with the transducer toward the first end wall as the stylus enters a pit, whereby the length of an acoustic water path is related to the pit depth.

Abstract: In an ultrasonic transducer arrangement having a plurality of ultrasonic oscillators, the ultrasonic oscillators each consist of a matrix of column shaped transducer elements, which are arranged in columns and rows. A planar array which can be addressed separately is formed from a matrix of such ultrasonic oscillators. This array permits focussing of the radiated sound in its longitudinal as well as transversal direction.

Abstract: An ultrasonic transducer has two impedance matching layers bonded to the transducer element which have different thicknesses and are 90.degree.-100.degree. and 35.degree.-55.degree. matching layers. This structure has a high sensitivity comparable to a broadband front surface matched transducer with quarter wavelength (90.degree. and 90.degree.) matching layers, and has primarily a single resonant mode so as to be suitable for relatively narrow band applications.

Abstract: A pulse-echo device for obtaining information about a flowing fluid in which a transducer unit comprises an electrically-shielded transducer with a lens for three-dimensionally focusing energy waves, which unit can be inserted into a hole extending through the sidewall of a pipe so that the energy waves focused by the lens are directed across the flow through the pipe. The transducer is surrounded by two electrically-grounded shields which are insulated from each other and separately grounded to isolated the transducer from stray electrical pulses.

Abstract: For testing wooden poles, a transmitter unit including a piezo electric transducer, energized to produce repetitive pulses of ultrasonic frequency, is held against the pole. The transmitter unit produces an audible sound synchronously with each ultrasonic pulse. A portable receiver unit having a probe coupled to a piezo electric transducer is held against the pole. This receiver unit includes a signal level comparator which causes a lamp to flash on for each received ultrasonic pulse above a predetermined amplitude. The receiver is held in a plurality of positions and readings are noted where the lamp flashes synchronously with the audible signal. From these readings the strength remaining in the pole to resist bending forces is calculated.

Abstract: A depth determining device has features for informing the operator of the depth of the cutting tool of a hydraulic drilling machine. The drilling machine is for earth boreing and has a piston carried in a cylinder and secured to a driven kelly. The device has a transducer mounted at the top of the cylinder for transmitting a sound wave through hydraulic fluid to the tap of the piston and detecting the return of the wave at the top of the cylinder. A counter determines the elapsed time for the sound travel. The elapsed time is converted into depth and displayed.

Abstract: A system is provided for detecting the absence of liquid in a liquid chamber. A signal is transmitted through a liquid chamber and a signal is provided in response to the amplitude of the received signal. A receiving transducer receives an AC signal which is amplified and fed to a DC control circuit. A reference voltage is provided to one input of a comparator and the output of the DC control circuit is fed to the other input of the comparator. The comparator output provides the liquid absence signal if the difference between the reference voltage and the DC control circuit output voltage is less than a predetermined value.

Abstract: An electrodynamic sound converter is disclosed for the non-destructive ultrasonic testing of workpieces during relative movement of the workpiece and the testing head. The testing head has an annular electromagnet which produces a magnetic field, and a rod-shaped core extends coaxially through the electromagnet and has a tip which projects beyond the same in direction towards the workpiece to be tested. The core is axially slidable relative to the electromagnet towards and away from the workpiece and the electromagnet and the tip of the core are each independently maintained at a fixed predetermined spacing from a surface of the workpiece being tested. The tip is being biased towards the surface, and a high-frequency coil is located adjacent the tip and serves to produce electromagnetic oscillations. Various modifications are also disclosed.

Abstract: A transducer for launching ultrasonic test signals is stimulated by an electrical signal which is of trapezoidal contour. Particularly the trailing edge of the signal is to decline at a rate similar at least as to order of magnitude to the rise time, and occurring in synchronism with a natural zero crossing of the vibration of the transducer to fully develop at least one full ultrasonic oscillation.

Abstract: The invention involves a digital synthetic-focus, acoustic imaging system which is operative in real time and includes one or more electro-acoustic transducers arranged to receive broadband pulses from a pulse generator for excitation of acoustic pulses which are directed into the region under observation. Signals reflected from an object or discontinuity in the region are received by the same transducers, and after inverse filtering and nonlinear amplification are converted to digital signals. These digital signals are stored in separate high speed random access memory units for storage, but are subsequently time-equalized through use of a programmed focus memory unit prior to delivery to a digital adder and thence through a digital-to-analog converter for ultimate intensity modulation on a raster scanned display unit which provides the real time image.

Abstract: In a focusing ultrasonic transducer with a recessed active surface, it is desirable that, given values of the focal width and of the focal distance prescribable as desired, an optimum lateral resolution with the smallest possible influence of side lobes ensues. This is achieved by means of manufacture in the following steps:(a) first, for focal width (F.sub.B) or focal interval (F.sub.A), the outer dimension (2a.sub.O) is determined as a function of the radius of curvature (R) of the transducer or the radius of curvature (R) is determined as a function of the outer dimension (2a.sub.O);(b) then the magnitude of outer dimension or, respectively, radius of curvature not yet determined is determined for the other of the two focal magnitudes (for example, F.sub.A); and(c) the maximum value of the angle of aperture of the sound radiation field behind the focus deriving in that manner is limited by means of a suitable selection of the size (2a.sub.