Abstract: An ultrasonic defect monitor for a moving workpiece is disclosed, including first and second test probes on opposite sides of an area of interest. The detected signals are processed for display by both a threshold monitor circuit, and an integrator-threshold-monitor circuit each connected to an output indicating unit for providing defect indications.

Abstract: An ultrasonic transmitting and/or receiving transducer is disclosed which includes a piezoelectric body with electrodes at opposite faces thereof. At least one of the electrodes is in the form of an elongated strip conductor such that the transducer also functions as a lossy delay line. The beam pattern of the transducer is dependent upon the delay of the delay line. A high permeability member such as a ferrite body is located adjacent the elongated strip conductor to increase the distributed inductance of the delay line and, consequently, the delay thereof. The permeability of the ferrite body is controlled by use of a drive coil adjacent thereto. By time varying the drive current to the coil, the acoustic beam pattern is time varied. By using a spiral shaped elongated strip conductor on a cylindrical shaped piezoelectric body, a focusing transducer is provided.

Abstract: The device comprises a transducer (1) which consists of two or more transducer layers (11) and (12) and which is connected to a transmitter circuit (2) which consists of a transmission network (21) and a control network (22) which comprises a first correction circuit (223) for the correction of the transfer function of the tranmission network (21). The transducer is furthermore connected to a receiver circuit (3) which consists of a receiver network (31) and an auxiliary network (32) which comprises a second correction circuit (323) for the correction of the transfer function of the receiver network (31). The correction circuits (223) and the (323) consist of an adder circuit with a number of inputs, each of which is connected to an output of a delay line (227i, 327i) whose input is connected to the output of an attenuator (226i, 326i).

Abstract: An ultrasonic inspection apparatus for inspecting a test piece includes an ultrasonic transducer for transmitting test signals into the test piece, for receiving associated response signals reflected back thereto, and for generating a defect signal when a response signal indicates an abnormal condition in the test piece. A control signal generator generates a control signal at predetermined intervals of distance of movement of the transducer relative to the test piece while the transducer generates test signals at a frequency independent the control signal frequency. A principal counter counts the control signals and generates an alarm signal when its count exceeds a value indicating that sufficient defect signals have been generated during movement of the transducer over a predetermined distance to confirm the presence of an unacceptable abnormal condition.

Abstract: An ultrasonic imaging apparatus comprises transducers for transmitting ultrasonic waves and receiving acoustic. The apparatus also transmits ultrasonic waves of different frequencies simultaneously from a plurality of transducers.The frequency characteristics of the transducers are determined in a manner so as to produce the function of frequency filters. An electric filter is additionally provided for compensation. Thus, crosstalk is eliminated even when the frequency difference between the transmitting ultrasonic waves is kept small.

Abstract: An automatic digital backfat meter. An apparatus and method primarily for measuring the thickness of backfat in an animal which automatically adjusts sensitivity and notifies the user when a proper reading is obtained. The transducer (62) produces pulses which pass amplifier (64), threshold detector (68), and are counted in counter (74). If two counts are received, indicator (76) is activated. If two counts are not received, the cycle is repeated and the amplifier (64) has its gain increased by sensitivity control (66) in a stepwise increment until indicator light (76) is activated. Time delay (78) prevents the first echo from being counted at counter (74).

Abstract: An ultrasonic method and apparatus are provided for detecting and imaging clusters of small scattering centers in the breast wherein periodic pulses are applied to an ultrasound emitting transducer and projected into the body, thereafter being received by at least one receiving transducer positioned to receive scattering from the scattering center clusters. The signals are processed to provide an image showing cluster extent and location.

Abstract: A dynamically variable electronic delay line for real time ultrasonic imaging systems is disclosed which controllably phases the signals associated with an array of electromechanical transducer elements and thereby enables selective scanning and dynamic focusing of a target. A controllable variable electronic time delay apparatus is coupled to each of the electromechanical transducer elements of the array having separate write-in and read-out addressing capabilities. The signals associated with a respective ultrasonic transducer element are fed in at selected write-in addresses and subsequently read-out and extracted after an initial time delay interval. The write-in and read-out address pointers of the memory system are continuously sequenced during operation of the device and the time delay interval is a function of the difference between the addresses and the clock rate.

Abstract: A three-dimensional ultrasonic scanning apparatus produces projection pictures on the surface of an object under inspection or examination and on planes perpendicular thereto. The amplitudes of the echo pulses produced by the ultrasonic scanning appartus, which uses an angle probe, are stored in a memory having at least one storage position relating to each projection of a reflecting point within the examined area. Only the highest echo amplitude originating from all the reflecting points lying on a projection line at right angles to the projection plane in question is recorded--not the highest amplitude from each reflecting point on the projection line. Thus, only those echo pulse amplitudes necessary to produce a projection picture of the object are stored in the memory thereby substantially reducing the required memory capacity.

Abstract: A device for testing sheet material, such as wood veneer, includes a rolling transducer for introducing ultrasonic signals into the veneer so as to cause travel of the signals generally in the plane of the veneer. Coupling oil filling this transducer facilitates the transmission of the signals into the veneer. Another similar rolling transducer is provided to detect the travelling ultrasonic signals. Each rolling transducer includes a special rim with an annular focusing ring for directing the ultrasonic signals to and from the veneer. A timer circuit produces a signal representing the travel time taken for an ultrasonic signal to pass between the transducers. An averaging circuit obtains an average of such travel times for each sheet and a grading circuit causes the sheet to be marked with a grade corresponding to the average travel time. A signal threshold detector prevents travel times for detected signals of a magnitude less than a preselected minimum level from being included in the average.

Abstract: A signal, which is the sum of an ultrasonic wave echo signal and a group of PPM (pulse-position-modulated) pulses representative of a reference signal, is applied to a cathode ray tube (CRT) and is swept along one axis by a first sweeping signal with a first frequency and along a second axis by a second sweeping signal of lower frequency. The ultrasonic echo signal and the group of PPM pulses are concurrently displayed on the CRT. Ultrasonic wave rate pulses synchronous with the first sweeping signal are applied at the first frequency to an ultrasonic transducer to emit ultrasonic waves which upon receipt are converted to an ultrasonic wave echo signal. A sawtooth wave generator circuit is provided for generating a sawtooth wave with a second frequency n times the first frequency. Here, n is an integer and equal to or larger than 2. The reference signal, such as an electrocardiographic signal, is modulated by the sawtooth wave to produce a train of pulse-position-modulated (PPM) pulses.

Abstract: In the illustrated embodiment, an electronic receiving gate is inserted between the image display device and the ultrasonic echo receiver so as to allow only echo impulses from a selected depth of field to pass through to the image display device. The depth selection is effected without any change in the line and image scanning rates by shifting the receiving gate between its transmitting and blocking states in the rhythm of the line sweep pulses and by adjusting the moment of emission of the ultrasonic pulses within the blocking phase of the receiving gate.

Abstract: An ultrasonic test system for inspection of structural material includes a test electronics for controlling a plurality of ultrasonic transmitter and receiver channels. This test electronics is operated by sequencing the system through the several channels, but the evaluating circuit is common to the receive channels. The duration of the test, timing of launching, timing of beginning receiving response signals, time and duration of looking windows for identifying and timing particular responses, and comparison data, all are operating and acquisition parameters for operating the electronics. These parameters are furnished from external sources and are programmable and exchangeable, e.g., from test to test. At least some of these parameters are updated on the basis of data as acquired during the test.

Abstract: A dynamically variable electronic delay line for real time ultrasonic imaging systems is disclosed so as to controllably phase the signals associated with an array of electro-mechanical transducer elements and thereby enable the selective scanning and dynamic focusing of a target. A controllable variable electronic time delay apparatus is coupled to each of the electromechanical transducer elements of the array and in one embodiment thereof constitutes an electronic memory having separate write-in and read-out addressing capabilities. The signals associated with a respective ultrasonic transducer element are fed in at selected write-in addresses and subsequently read-out and extracted after an initial time delay interval. The write-in and read-out address pointers of the memory are continuously sequenced during operation of the device and the time delay interval is a function of the difference between the addresses, as well as the clock rate.

Abstract: Ultrasonic response signals resulting from interaction of a test pulse with the structural material are recognized by dynamically tracking the noise level and adding thereto a fixed level; a response signal to be recognized must exceed the resulting variable threshold level.

Abstract: Apparatus and method for producing maps of thickness or elastic constant iations of nominally plane sheet or plate materials. Amplitude variation at a set frequency on a normal resonance peak is recorded to determine resonance peak variation and thus specimen thickness or elastic constant variation. A mechanical scanner moves a transducer across the material submerged in a water tank for performing an ultrasonic C-scan. A transmitter or pulse generator repeatedly pulses the transducer to produce a focused narrow pulse of ultrasound which reverberates within the material. Echoes from the material in response to the pulse are received by the same or another synchronously moving transducer, whose resulting signal then passes through a gate, which removes extraneous signals and selects the number of multiple echoes and thus amplitude range desired, and a variable filter controlled by a function generator which selects the desired frequency, to a pen recorder.

Abstract: An ultrasonic nondestructive testing system of the pulse-echo type is disclosed including an echo-signal-translator exhibiting a bandwidth that is varied to achieve excellent near-surface resolution while affording deep inspection of an object under test.

Abstract: A system for inspection of adhesively bonded structures utilizing a piezoelectric transmitting transducer for transmitting a fixed frequency tone burst, e.g., 25 KHz, at a predetermined repetition rate, e.g., 100 Hz, into a part being tested and including a piezoelectric receiving transducer also coupled to the part for providing in a receiver circuit an audible output which permits the operator to distinguish amplitude variations of the 100 Hz repetition rate signal representative of the presence of an unbonded area.

Abstract: A method and apparatus for excitation and reception of ultrasonic plate waves in a workpiece in which the surface of the workpiece is acted upon by a high-frequency electromagnetic field excited by a system of flat radiators forming a comb-shaped structure and positioned discretely in the direction of radiation with a pitch divisible by the wave length. A magnetizing field, whose vector is parallel to the surface of the workpiece under test, is introduced into the workpiece in the area of the high-frequency electromagnetic field and the vector of the magnetizing field is arranged at an angle relative to the radiation direction with respect to the flat radiator array to excite transverse normal waves.

Abstract: A diaphragm formed in a substrate and having a piezoelectric surface includes a first surface acoustic wave (SAW) delay line disposed on said surface and connected in an oscillator circuit for a significant frequency sensitivity to surface strain of said diaphragm, and a second, similar oscillator with the SAW delay line thereof connected for a significant frequency sensitivity to surface strain of the diaphragm opposite in sense to that of the first oscillator, and a mixer for providing the difference in the frequencies of the two oscillators, whereby the overall sensitivity to strain is enhanced, while at the same time the sensitivity to temperature variations is reduced significantly through subtractive combination.

Abstract: In order to increase the speed at which a workpiece is tested by the ultrasonic pulse-echo method, the dead time between individual measurement time intervals is shortened by providing a minimum predetermined time interval selected for the specific test conditions. When an echo responsive signal is manifest in the receiving circuit, in order to prevent the occurrence of phantom echo signals arising in the following measuring interval, the generation of the succeeding transmit signal is inhibited for the predetermined time interval after receipt of the last echo responsive electrical signal of the measuring interval having an amplitude exceeding a predetermined minimum amplitude. The test speed therefore, is made adaptive to the condition of the receipt of the number of echo responsive electrical signals exceeding a predetermined minimum amplitude.

Abstract: The effective thickness of a piezoelectric unit comprising a plurality of contiguous layers is varied by selectively short circuiting one or more layers with switch means. This varies the electro-acoustic properties at an operating frequency that is exhibited between the respective acoustic ports of the unit and an electrical circuit coupled across the electric port of the unit. Specific embodiments of such a unit, switch means and electrical circuit are useful in a control device for acoustic-wave propagating systems.

Abstract: An ultrasonic scanner having a housing, an ultrasonic transducer disposed within the housing and mounted for movement in a predetermined path therewithin. Magnetic means are provided for effecting movement of the transducer in a predetermined path, and electrical means are provided for energizing the transducer and receiving signals therefrom.The scanner may be servo-controlled and be provided with position sensing means for determining the position of the transducer within the predetermined path, and signal processing means for receiving feedback signals from said position sensing means and adjusting said transducer position responsive to said feedback signals indicating the existence of a departure from the desired transducer position.

Abstract: Short bursts of ultrasonic energy are directed through a three-dimensional specimen to determine the spatial distribution of those structures within the specimen capable of affecting the waveform of the energy. Transducers are placed in spaced positions about the periphery of the specimen to measure the affected parameters (such as attenuation and delay time) of the energy as a result of passing through the specimen along paths between the spaced transducers. The output signals containing this transit time and energy absorption information are retained in a data storage device. Through conventional programming techniques, a computer processes the data and calculates a velocity or absorption profile for each path. The profiles are collectively used to reconstruct two-dimensional or three-dimensional images of the specimen.

Abstract: Ultrasonic reflections are received by a transducer array whose resultant signals are passed through an array of time-varying delay lines to provide focusing at all depths. The delay lines are made up of a combination of two components, one increasing and one decreasing with the distance to the axis of the array. This combination minimizes the range of delay variations required over the depth range. When using charge coupled devices as delay elements, this combination minimizes the required range of clock frequencies.