Abstract: A structure including a substrate and a coating over the substrate is acoustically excited to measure acoustic response in the structure. The measured acoustic response in the structure is filtered to remove acoustic response of the substrate and determine acoustic response of the coating. The acoustic response of the coating is used to inspect the coating for failure.

Abstract: A method for providing a digital sensor signal (DS) from an ultrasonic sensor (16) for signal transmission to a signal receiver (28) is disclosed, in which a digital output signal (OS) from the ultrasonic sensor (16) is processed to form the digital sensor signal for signal transmission. Provision is made for the processing to comprise the following steps: (i) determining a signal change (SC) of successive values of the output signal (OS), (ii) scaling this signal change (SC) by means of a variable scaling factor (SF) which is specified by a scaling scheme known to the ultrasonic sensor (16) and the signal receiver (28), and (iii) outputting the scaled signal change (SC) as the digital sensor signal (DS).

Abstract: A central member defines a sample chamber and includes an elastic material configured to enclose at least a portion of a sample, acoustic sensors configured to detect sound waves in the sample chamber, and acoustic emitters configured to emit sounds waves in the central member. A pressure-retaining case is configured to contain a pressurized fluid between an annulus formed between the pressure-retaining case and the central member. A switch is configured to connect or disconnect a pulser and receiver circuit to a specified emitter of the acoustic emitters. A data acquisition unit is configured to receive a signal from each of the acoustic sensors. A pulser and receiver circuit is configured to send an electric pulse to an acoustic emitter and a control signal to the data acquisition unit.

Abstract: A method for measuring a mean visco-elasticity value for a soft material uses a single probe carrying at least one transducer. At least one burst of mechanical vibrations is induced in a constraint zone in order to generate internal shear waves in the tissue propagating from the constraint zone into the tissue. The transient tissue displacements are measured with a transducer in at least one first measurement zone in the tissue, the first measurement zone being located away from the constraint zone. A mean visco-elasticity of the region of the tissue situated between the constraint zone and the first measurement zone is estimated from the measured transient tissue displacements of the tissue in the first measurement zone.

Abstract: Disclosed is a calibration system and method for a phased array ultrasound pipe inspection system, in which reliable calibration is obtained for notches at all angles using only a small number of notches for the calibration. The method comprises a one-time normalization step and a system calibration step which may be performed at regular intervals. Ultrasound transmission is in a single diverging beam for each aperture, while reception is selective for multiple well-defined reception angles. During the normalization step, plots of maximum response vs reception angle are plotted for each notch, and a normalization curve is constructed by fitting the maxima of these plots. The normalization curve is used to derive calibration targets at specific reception angles for specific calibration notches, which are then used for the system calibrations.

Abstract: Embodiments relate to a method for ultrasonic testing according to the pulse-echo method as well as an arrangement for performing such a method. By means of an ultrasonic transducer, an ultrasonic pulse is obliquely incident into a sound incidence surface of a test object. Next, an echo signal is received from the test object. This takes place either by means of the ultrasonic transducer, which has emitted the ultrasonic pulse or with another ultrasonic transducer. The time amplitude characteristic of the echo signal is evaluated in a predefined defect expectation interval of time. The evaluation step includes, in at least one section of the amplitude characteristic, an amplification of the amplitude and/or a reduction in the threshold value. For example, the amplitude of the received echo signal is then compared with the predefined threshold value.

Abstract: An ultrasonic flaw detecting apparatus including: a transducer including a piezoelectric element array for transmitting ultrasonic waves to and receiving echo signals from a test object; an element driving unit for scanning the piezoelectric element array at a predetermined cycle and generating the ultrasonic waves; a synthesizing unit for synthesizing an internal image of the test object based on the echo signals received by the piezoelectric element array; and a signal replacing unit for replacing the received echo signal with an echo signal in which a bottom echo of the test object is removed.

Abstract: Embodiments contemplate methods and devices for conducting ultrasound interrogation of a medium. An ultrasound echo wave may be received at a first transducer element of a transducer array in a handheld probe. The ultrasound echo wave may also be received at a second transducer element of the transducer array. The ultrasound echo wave may also be received at a third transducer element of the transducer array. The handheld probe may process into digital data the ultrasound echo wave received at the first transducer element and the ultrasound echo wave received at the second transducer element. The processing may preclude data representative of the ultrasound echo wave received at the third transducer element from being included in the digital data. The processing may include reducing the digital data and the reduced digital data may be transmitted to a location relatively remote from the handheld probe.

Abstract: The disclosed embodiments include a method, system, and device for conducting ultrasound interrogation of a medium. The novel method includes transmitting a non-beamformed or beamformed ultrasound wave into the medium, receiving more than one echoed ultrasound wave from the medium, and converting the received echoed ultrasound wave into digital data. The novel method may further transmit the digital data. In some embodiments, the transmitting may be wireless. The novel device may include transducer elements, an analog-to-digital converter in communication with the transducer elements, and a transmitter in communication with the analog-to-digital converter. The transducers may operate to convert a first electrical energy into an ultrasound wave. The first electrical energy may or may not be beamformed. The transducers also may convert an echoed ultrasound wave into a second electrical energy.

Abstract: A method and a device for detecting discontinuities in a material region having at least one probe which has a plurality of ultrasonic transducer elements and having an evaluation and control device are proposed, in which the transducer elements are disposed diagonally at an angle to the surface of the material region and are actuated via delay elements in such a manner that a defocusing sound field is beamed in. The received signals of the transducer elements are supplied to a plurality of evaluation modules for parallel and simultaneous further processing for different angle values or angle ranges, the number of evaluation modules corresponding to the different angle values or ranges.

Abstract: One surface of a component is obliquely ensonified through a liquid or gaseous first medium with a checking sound beam produced by a transmission/reception transducer for defect investigation of the component. A response sound beam, which is reflected back from the surface to the transmission/reception transducer, is received and its delay time in the medium between the transmission/reception transducer and the surface is evaluated. The delay time in the medium determined in this way is taken into account for localization of a defect within the component.

Abstract: An impulse line-clogging detecting apparatus. The apparatus is provide with: a differential pressure detecting unit that detects a differential pressure of a fluid, and outputs time-series data of the differential pressure. Fluctuations are determined by a differential pressure fluctuation calculating unit that calculates a differential pressure fluctuation, and a fluctuation variance calculating unit that calculates a variance of the differential pressure fluctuation. Based upon the calculated variance, a variance ratio calculating unit calculates a variance ratio of the differential pressure fluctuation variance to a differential pressure fluctuation variance obtained in advance in a normal state of the high and low pressure side impulse lines. A variance ratio correcting unit calculates a correction value for suppressing a change of the variance ratio.

Abstract: Diagnosing operation of an impulse piping line in an industrial process is provided. A vibration source transmits a vibration signal through the piping and a vibration signal receiver receives the vibration signal. The operation of the impulse piping line is diagnosed, such as failure or impending failures, based upon the received vibration signal.

Abstract: A preventive defect detection and control process for a mass produced composite material parts automatically obtains representative parameters of backwall and intermediate echo signal results in each cell of a mesh predefined on the parts, stores the parameters in a database and statistically analyzes the stored parameters for detecting isolated and significant alterations in the parts manufacturing process generating porosity defects, detecting slow and permanent alterations in the parts manufacturing process generating porosity defects or detecting areas with a negligible defect generation probability in order to identify areas susceptible of inspection by sampling.

Abstract: The disclosed embodiments include a method, system, and device for conducting ultrasound interrogation of a medium. The novel method includes transmitting a non-beamformed or beamformed ultrasound wave into the medium, receiving more than one echoed ultrasound wave from the medium, and converting the received echoed ultrasound wave into digital data. The novel method may further transmit the digital data. In some embodiments, the transmitting may be wireless. The novel device may include transducer elements, an analog-to-digital converter in communication with the transducer elements, and a transmitter in communication with the analog-to-digital converter. The transducers may operate to convert a first electrical energy into an ultrasound wave. The first electrical energy may or may not be beamformed. The transducers also may convert an echoed ultrasound wave into a second electrical energy.

Abstract: In accordance with one embodiment, the present technique provides a testing apparatus for testing material integrity of an object. The exemplary testing apparatus includes a phased array transducer, which is disposed external to the object. The phased array transducer is configured to transmit a first set of ultrasonic signals and to receive a second set of ultrasonic signals. The testing apparatus further includes logic circuitry coupled to the phased array transducer. The logic circuitry is configured to dynamically control apertures for transmitting the first set of ultrasonic signals and receiving the second set of ultrasonic signals based on a region of interest and a testing speed.

Abstract: A welding system includes a device for evaluating an ultrasonic signal during a welding process. The device has a meassured value evaluation unit that, in normal operation, evaluates at least one measurement signal that is derived from an ultrasonic signal and is located inside a measurement window. A mechanism for establishing the measurement window is provided, which establishes the measurement window according to a measurement signal that is received in a calibration operation.

Abstract: An internal inspection unit for pipe has ultrasonic transducers that inspect weld volume, weld root, and wall thickness. The ultrasonic transducers are mounted to a portion of the inspection unit that is rotatable, but no more than one full revolution. One of the units has independently movable shoes for each separate transducer. The shoes are moved between retracted and extended positions by pneumatic cylinders. The other unit has shoes that support more than one transducer, the shoes being biased outwardly by springs.

Abstract: An array of dual-element transducers for automated, ultrasonic inspection of a weld seam in austenitic material is configured through the use of a schematic representation of the weld seam. The weld is divided into zones, and separate transducers are selected to inspect each zone. A creep-wave transducer is used to inspect the uppermost zone, and an L-wave transducer is used to inspect a lower zone. The L-wave transducer is connect to a computer processor to serve “double-duty” : it is used with one set of gate and gain settings to process direct reflections of the emitted sound, and with another set of gate and gain settings to process indirect, mode-converted reflections of the sound. Gate settings are determined by measuring sound path distances from the schematic. Test plates are used to determine sensitivity settings, and to confirm adequate width of field for each transducer.

Abstract: An array of dual-element transducers for automated, ultrasonic inspection of a weld seam in austenitic material is configured through the use of a schematic representation of the weld seam. The weld is divided into zones, and separate transducers are selected to inspect each zone. A creep-wave transducer is used to inspect the uppermost zone, and an L-wave transducer is used to inspect a lower zone. The L-wave transducer is connect to a computer processor to serve “double-duty”: it is used with one set of gate and gain settings to process direct reflections of the emitted sound, and with another set of gate and gain settings to process indirect, mode-converted reflections of the sound. Gate settings are determined by measuring sound path distances from the schematic. Test plates are used to determine sensitivity settings, and to confirm adequate width of field for each transducer.

Abstract: An ultrasonic testing system can receive data from at least two ultrasonic transducers and process the data in parallel to each other. The testing system can compress the data by a fixed ratio by storing the value of the sample having the highest-amplitude out of a group of samples. The testing system can also provide threshold-based run-length encoding by compressing data by only storing samples which exceed a user-defined threshold value as well as a user-defined range of samples surrounding said samples. The ultrasonic testing system also provides a hardware gate for storing a peak amplitude and associated time-of-flight for a user-defined interval and a gate for storing the time-of-flight for the first excursion of the data through a user-defined threshold and interval. The operation of these gates or the storage of waveform data may be delayed by a constant delay or until the data exceeds a user-selectable threshold during a user-selectable time interval.

Abstract: In a measuring method and a measuring apparatus which are suited for observing a dynamic physical phenomenon particularly in a microdevice, a signal for generating a physical phenomenon in a specimen is inputted to the specimen, and a signal which is caused by this dynamic physical phenomenon is detected by a probe which is close to or in contact with the specimen surface in correspondence with a signal input to the specimen on the basis of the specific time. The measuring apparatus has a scanning probe microscope with a probe (tip) which is close to or in contact with the specimen surface, a pulse voltage application control unit for applying respective pulse voltages to the specimen and probe, and a signal measuring unit for measuring a signal from the specimen detected by the probe.

Abstract: A method and apparatus for discriminating a valid return pulse from noise in a return signal received by an ultrasonic transducer in response to an interrogating pulse transmitted into a wall of a gas pipe by an ultrasonic transducer of a scan assembly. A discriminator is provided to compare the return signal with adjustable reference voltage thresholds which are continually adjusted by a discriminator computer in accordance with the noise characteristics of the return signal.

Abstract: In an ultrasonic inspection and imaging instrument, a pulse generator and a burst wave generator are provided in association with the activation of an ultrasonic probe by the pulse generator and in response to a measurement value obtained from a signal reception circuit portion. A first gate position is obtained with regard to an inspection portion in a sample, and then a second gate position for a burst wave measurement is set by correcting the first gate position. The burst wave measurement is performed by activating the burst wave generator.

Abstract: This invention relates to control systems for the control of noise and vibration. Resonators with adjustable properties are used in conjunction with an electronic control system to change the noise or vibration in a structure. The invention relates particularly to the control of quasi-periodic noise or vibration comprising one or more harmonics by using one or more adaptive resonators.

Abstract: A method and apparatus for acoustic analysis of binary gas mixtures. A binary gas sample is drawn into a first chamber. A known reference gas is drawn into a second chamber. Acoustic energy is simultaneously transmitted through the respective chambers. Arrival of the first acoustic wave at the receiver of the reference chamber starts a counter that isolates a selected received pulse. The time between receipt of that selected reference pulse and the very next sample pulse is monitored and is transferred to a short term memory and then returned to its initial zero condition. After a quiescent time delay, the sequence is repeated. The resulting signal may be output as data and/or activate alarms if the output does not remain between predetermined upper and lower thresholds, thereby indicating an undesirable binary gas mixture.

Abstract: An ultrasonic edge detector system wherein the lateral position of a moving web or sheet is monitored by projecting an ultrasonic beam from a transmitting transducer toward a receiving transducer and the web edge occludes or shadows more or less of the ultrasonic beam changing the ultrasonic energy received by the receiving transducer. Changes in output of the receiving transducer are detected as a measure of change in edge position. Accuracy in the measurement of the position of the edge is achieved by lengthening the path of acoustic energy from the transmitting transducer to the receiving transducer by positioning an acoustic reflector in said path. Reverberations are reduced by causing the angle of incidence of the ultrasonic beam to be at an angle .alpha. of greater than 0 degrees. A dual receiving transducer system is disclosed compensating for fluctuations in power to the edge detector system.

Abstract: Ultrasonic wave converged by an acoustic lens is made incident onto a sample and wave reflected from the sample is received and converted into received electric signal by a transducer. A part of this electric signal is picked up by a gate section and the signal thus picked up is applied to an attenuator where it is converted into a variable ratio of input to output. The strength of the signal thus gain-adjusted is compared with a threshold value by a comparator. Responsive to the comparison result thus obtained, the gain of the attenuator is adjusted to make the input/output ratio of the attenuator a desired value. A computer calculates the focus position of the acoustic lens from a gain curve of the attenuator changing when the acoustic lens is moved from a position, remote enough from its focus position, to the sample. Drivel signal responsive to the result thus calculated is applied to a Z-drive control section.

Abstract: In the process whereby a time gate but especially the time gate for an expected error range 58 in a device by means of which materials are tested by ultra sound according to the impulse echo process involving a test head 20 which emits pulses that impinge diagonally on the surface 28 of a test piece 24, the test head 20 that emits diagonally is firmly connected to a test head 22 from which pulses are emitted vertically. Both test heads emit at given intervals 48, 49 ultra sound impulses and subsequently receive them. The echo signal 50 of the entry of sound of the test head 22 from which pulses emit vertically is utilized to activate the time gate of the test head from which sound is emitted diagonally.

Abstract: A delay time measurement method for ultrasound of the type wherein a testing head transmits an excitation pulse that is as close as possible to the shape of a shock wave and traverses a pretravel path until it reaches the object to be examined which has a front wall and a rear wall, with at least one reflected pulse being generated at its front wall as well as at its rear wall. To improve the above-mentioned type method so that delay time measurements for thickness determinations and abnormalities can be performed reliably even on rough surfaces and if reflected pulses are missing or falsified, a time window is determined for the recording of reflected pulses that follow the excitation pulse, within which window all successive reflected pulses are digitized.

Abstract: A three dimensional object under test is measured to obtain shape data representing a shape of the three dimensional object. The object under test is measured using, for example, an ultrasonic probe LED to obtain defect test data. A processing mechanism forms a three-dimensional graphic image of a defect zone from the defect test data and a three-dimensional graphic image of the object under test from the shape data. A display mechanism is provided for displaying the three-dimensional graphic image of the defect zone superimposed over the three-dimensional graphic image of the object under test.

Abstract: The present invention is comprised of a non-intrusive microwave sensor system for measuring fluid saturation or multiple fluids contained within a flowline or a fluid saturated porous medium. Here, the microwave oil saturation scanner (MOSS) comprises a transmit portion and a measurement portion. The transmit portion generates two signals for different purposes. The first signal is used as a reference signal upon which the sample signal is eventually compared. The second signal is transmitted through the sample which causes a phase angle shift and signal attenuation. The two signals are then compared in the measurement portion where the phase angle shift and the signal attenuation is related to the concentration of oil and water in the sample mixture.

Abstract: An acoustic ash depostion monitoring apparatus for a boiler arrangement having at least one soot blower. The apparatus comprises at least one tone generating apparatus for generating a tone and at least one tone receiving apparatus, located in proximity to the tone generating apparatus, for receiving the tone generated by the tone generating apparatus. Also provided are controlling apparatus for determining when the tone received by the receiving apparatus falls below a predetermined level and for enabling a soot blower in proximity to the tone generating and tone receiving apparatus when the tone received by the receiving apparatus is determined to have fallen below the predetermined level.

Abstract: An echo tracker clamps a time window for detecting an echo at the position of an echo produced by a mobile wall receiving an ultrasonic pulse signal at a repetition rate F.sub.r. It includes a depth counter (28) which counts in order to define the beginning of the time window in relation to a pulse of the pulse signal and which when it reaches a given value, supplies an enabling signal to activate authorization means (30) and a position detector (32).Enabling means (30) provide an enabling signal for a given time which defines the detecting time window. During this time, the position detector counts until the echo is detected. The value reached at that instant is used to clamp again the time window and to modify the initial value of the depth indicator.The invention is useful in the medical field for measuring the changes of the position of an interface between two tissues.

Abstract: A multi-channel ultrasonic inspection system includes an ultrasonic inspection unit which generates ultrasonic inspection pulses, supplies the pulses to a part being inspected, produces an output signal proportional to the level of echo pulses received within a predetermined gate time window following generation of the inspection pulses, and generates an alarm signal whenever the output signal exceeds a predetermined gate level. The system also includes data recording apparatus having a microcomputer, a mathematics processor chip, a control panel, and a printer. A gate reference level for each channel is stored by the microcomputer by pressing a channel button on the control panel, supplying inspection pulses to a workpiece having a standard defect, and adjusting the gain or gate level of the ultrasonic inspection unit until an alarm signal is generated. The operator then presses a START button which causes the reference levels to be printed.

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 multiplexor 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. Calibration means are provided for correcting the output signals produced by the receiving transducers to compensate for variations in the response of individual transducers.

Abstract: In a rotor binding inspection device comprising a self-powered carriage movable about the rotor shaft and a probe-carrying arm carried by said carriage and operable to move longitudinally parallel to the axis of the rotor between the stator and the rotor binding, said arm carrying at its extremity two detector units each comprising a right angle, longitudinal wave probe and an oblique angled, transverse wave probe, additional means are provided for recording the right angle probe echoes, for recording the angled probe echoes and for defining for the angled probes, based upon the indications from the right angle probes, a variable detection threshold.

Abstract: The invention relates to a method and a device for measuring the wall thickness of bodies by means of ultrasonic pulses. The ultrasonic pulses are created in the bodies and reflected on the walls. The transit times of the ultrasonic pulses reflected on the walls are measured. The wall thickness is determined from the transit times by considering the respective sonic speed in the body. The measured signals obtained with a receiver are each compared with a threshold value that is set to a low base value (17a) at the beginning of the measurement. With each measured signal exceeding the associated threshold value (17a, 17b, 17c, 17d respectively) the threshold value is reset to the amplitude of the measured signal. The times from a specified starting time are measured up to the measured pulses that exceed the threshold values. The maximum value of the time corresponds to the transit time of the back wall echo (13).

Abstract: The invention relates to an ultrasonic test instrument for the nondestructive testing of materials. The instrument includes a transit time measuring circuit and an amplitude and time gate circuit. According to the invention, to measure the amplitudes and the corresponding transit times of a number of echo signals falling within a predetermined measurement range, the output of the amplitude and time gate circuit is connected to the input of a presettable counter which outputs a signal whenever the number of counted pulses is equal to the preset value of the counter. The counter output is connected to the transit time measuring circuit and by way of a second time gate circuit to the amplitude measuring circuit so that amplitude evaluation is carried out only during the time interval defined by the second time gate circuit.

Abstract: The invention relates to a method of suppressing unwanted indications in automated ultrasonic testing of a test piece.In order to improve the suppression of unwanted indications, in particular in the case of extended statistical suppression, a variable discriminator threshold (3) is derived from the highest of all maximum amplitudes (2) by means of a predetermined amplitude difference (4), wherein the ultrasonic signals are not evaluated as flaw signals when only said variable discriminator threshold (3) is exceeded but are evaluated as flaw signals only when additionally at least the highest of all maximum amplitudes (2) exceeds the fixed discriminator threshold (1) preset for the testing operation.

Abstract: A method and apparatus for detecting disbond in laminar workpieces. Energy is transmitted to a workpiece (8) by repetitive impacts. A transducer (12) converts energy emitted from the workpiece (8) to an electrical signal. The energy emitted in response to each of the repetitive impacts is analyzed. After filtering out the DC component (20) and amplifying the signal (30) the maximum amplitude of the energy from each impact is selected (50) and passed to a sample and hold circuit (60). The piecewise linear output of the sample and hold circuit (60) is passed through a low pass active filter (70) prior to recording on a strip chart recorder. The strip chart record is analyzed to ascertain areas of the workpiece (8) having defective clad bonding (7).

Abstract: The invention relates to a method for testing fuel element tubes by ultrasonic energy. For testing, each tube becomes disposed in the space between a transmit transducer and a receive transducer. The echo signals falling within a predetermined time interval are evaluated. Since the distance between the transducers may vary as the transducers move through the space between fuel element tubes, the transmitted signal reaching the receive transducer without passing through the tube may be confused with the revolving echo signal. Therefore, this invention discloses an arrangement for cyclically controlling the setting of the time gate before each such tube is in position between the transducers. To this end, the ultrasonic transit time of signals between the transmit transducer and the receive transducer is measured in the gap between the last tested tube and the next to be tested tube.

Abstract: The invention relates to an ultrasonic test instrument, in which a receiver amplifier is controlled in dependence upon time by means of a depth compensation signal or else the ultrasonic signal amplified independently of the depth is evaluated by means of a time-dependent variable threshold signal. The depth compensation signals and the time-dependent threshold signals are derived from the same digital signal values stored in a main memory. The test instrument comprises a microprocessor by means of which the digital signal values for each material requiring testing are automatically measured by the instrument itself in conjunction with whichever test probe is used provided a corresponding test block of this material is available.

Abstract: In order to safely interfering signals caused by interfering volumina like e.g. air bubbles existing in a coupling medium from signals generated by workpiece defects in the ultrasonic testing of workpieces according to the pulse-echo-method, it is suggested that at the appearance of a signal in the time between transmitting pulse and surface echo-signal crossing an adjustable threshold during a test cycle, all signals of the same test cycle falling within the range of anticipation for workpiece defects will be suppressed.

Abstract: A circuit for adjusting the sweep time provided by a sweep generator used in an ultrasonic test instrument is described. The adjustment takes into account three test parameters, i.e. the angle of propagation of the sound in the workpiece, the speed of propagation of sound in the workpiece, and the thickness of the workpiece. To this end, the quartz-stabilized frequency of an oscillator comprising an adjustable frequency divider is divided by the angle function value of the angle of sound propagation to which the test instrument is set. The divided frequency is fed to a frequency multiplier in a phase locked loop circuit, comprising an adjustable frequency divider by means of which the speed of propagation of the sound is adjusted. A succeeding time reference stage contains also an adjustable frequency divider by means of which the workpiece thickness is adjusted.

Abstract: Plate stock of uneven and variable thickness is tested for defects by means of ultrasonics whereby the zone adjacent the front surface and up to a depth of the minimum plate thickness is detected conventionally, but under utilization of a novel method the zone of variable thickness adjacent the rear wall is tested by detecting any echo in a gating period (15) that is returned from that zone or from the rear wall, and such an echo is used to set up a supplemental gating period during which either none or the rear wall echo will occur and in the latter case the setting up of the supplemental gating period is interpreted as having resulted from the presence of a defect (for example, echo 12) so that the occurrence of the rear wall echo 9 within the supplemental gating period is registered as an indication of a defect.

Abstract: Multi-channel automatic on-line ultrasonic inspection system for real time high-speed pulse echo testing is done across the width of a hot moving workpiece, such as steel plates and the like. In addition to a multiplexed transducer array search unit, the system includes an adjustable ultrasound fluid couplant, a main ultrasonic instrument modified with a digital multi-channel R.F. attenuation controller and a digital automatic flaw gate controller combined as on-line calibration means. The calibration means automatically corrects echo pulses for attenuation errors due to effects of variations in workpiece alloy or composition and temperature, and timing errors due to effects of variations in thickness and transducer gap, respectively. System further includes an ultrasonic data buffer/controller (UDBC) for digitizing, encoding and storing corrected or uncorrected flaw area data passed by the flaw gate during workpiece movement.

Abstract: An ultrasonic test instrument includes a pulse generator, a receiver, a cathode ray tube screen display and a time gate means providing a gated time interval for viewing only echo signals which arise from a predetermined workpiece region under test. The time gated interval is shown as a horizontal gate bar display on the screen and the length of the bar being indicative of the gated time interval. Circuitry provided generates a reference signal to cause the gate bar to appear at a height commensurate with the echo signal received in the gated intervals having the highest peak amplitude. Unless reset, the amplitude of the gate bar remains at this peak value although subsequent echo signals may have a lower amplitude.

Abstract: The results of the non-destructive testing of objects with a beam of ultrasonic energy is enhanced by generating display control signals commensurate with a precisely defined region in the test object. These region related signals may be displayed as a "gate" bar on the screen of a cathode ray tube simultaneously with the display of echo related signals. Echo related signals having a magnitude greater than a threshold level, as also defined by the "gate" bar, are detected and may be employed to energize an alarm.

Abstract: Apparatus to detect and/or locate an inhomogeneity in a medium comprises a transducer to transmit frequency-modulated ultrasonic energy through the medium and a transducer to receive reflected energy. The transducers are connected to a phase-locked loop which maintains a required relationship between the phase of the transmitted modulation and the phase of the received modulation by adjustment of the modulation frequency. The modulation frequency adjustment is kept within predetermined upper and lower frequency limits so that the loop can lock only on to received ultrasonic energy which has travelled a distance within a predetermined region in the medium. The energy may be scanned across the region to produce a profile of the inhomogeneity, such as tissue at a certain depth within a limb.