Abstract: An apparatus and method for scanning a body of water for fish and other underwater articles with a sonar depth finder of a type having a transducer that can transmit an acoustic wave and receive sonar returns on both a narrow acoustic wave beam mode and on a wide acoustic wave beam mode, in which the sonar depth finder repetitively determines the approximate depth of the body of water by repetitively transmitting in the wide beam mode and receiving and displaying the sonar returns from each transmission initially in the wide beam mode and then in the narrow beam mode, with the duration of receiving in the narrow acoustic wave beam mode being a function of the determined depth from a prior transmission.

Abstract: A method and system for compensating for steering anomalies by adjusting aperture in steered phased array transducer systems adjusts the aperture of a transducer array to effectively compensate for the steering anomalies. The aperture of the transducer array can be varied depending upon the steering angle of the beam and the resultant steering angle anomalies.

Abstract: The invention pertains a bathymetric sonar system involving a single swept transmit beam projector system which compensates for ship attitude and positioning changes. A sonar transducer array has a matrix of acoustic projector elements arranged in a plurality of substantially parallel rows and a plurality of substantially parallel columns; and means for causing each of the projector elements to generate an acoustic signal at a frequency and phase independently from each other projector element. Preferably the transducer array is operated by causing the projector elements to generate an acoustic signal at a frequency and phase independently from each other projector element, at a frequency and phase which is initially the same as the frequency and phase of each other element in its column and such that the frequency and phase of the projector elements in each column is different from each other column. Thus a single swept beam is projected toward the ocean floor.

Abstract: The interferometer, which is preferably in the form of a sonar, can have a single projector array and a single receiver array. The projector array comprises a first subset of projector elements that function as a first pseudo projector and a second subset of projector elements that function as a second pseudo projector. One or more of the projector elements belong in both the first and the second subsets, such that one or more of the projector elements function as part of both the first and the second pseudo projectors. A receiver is operative for receiving reflected portions of the signals emitted by the pseudo projectors. A processing system analyzes the signals received by the receiver to at least partially determine the position of an object.

Abstract: New apodization functions providing an effective rejection of side lobe amplitude level within wide range of beam steering angles are described in this invention. A central amplitude apodization function (13) reduces amplitudes for the central section of transmit and receive array individual elements. A time apodization function (14) changes a duration of transmit pulses. A duration of transmit pulses is short for central section of transmit array and increases for outlying transmit individual elements. A frequency apodization function (15) changes frequency of transmit pulses for different transmit individual elements. The use of new apodization function allows realization of portable acoustic scanners. Some versions of a portable acoustic scanner design and a version with time compression of echo signals are described.

Abstract: A sonar sensor array having a multi-layer tiling arrangement for the indiual elements that increases surface area available for each element while maintaining the inter-element spacing required to avoid spatial aliasing when the received signals are combined to form a sonar beam. The array comprises outer and inner arrays of transducer elements for converting an acoustic signal to an electrical response. The transducer elements of the outer array are positioned such than a grid of isolation spaces separates each of the transducer elements. The transducer elements of the inner array are also positioned such that a grid of isolation spaces separates each one of the transducer elements. The electrical response generated by the transducer elements of the inner and outer arrays are coupled to a beamformer which processes the responses to produce an output signal.

Abstract: An acoustic imaging apparatus and method that achieves desired delays with coded signals. Linear, curved linear and sector scanning is provided in 1-D arrays and planar, curved planar and sector scanning is provided in 2-D arrays. Composite and non-linear implementations are presented. Dynamic and discrete dynamic focusing is disclosed for the relevant arrays. The 2-D array makes possible 3-D imaging.

Abstract: A sonar array which has a resolving power which is double that of convental sonar arrays includes an array of hydrophones each having an acoustic center, a first projector positioned proximate a first endmost one of the hydrophones for launching a first sound signal during a first transmission time period, a second projector positioned proximate a second endmost one of the hydrophones for launching a second sound signal during a second transmission time period, wherein the hydrophones receive first echo signals and convert the first echo signals into first electrical echo signals during the first transmission time period, and receive second echo signals and convert the second echo signals into second electrical echo signals during the second transmission time period, and, a receiver for receiving and storing the first and second electrical echo signals, and for coherently summing the stored first and second electrical echo signals, to thereby produce a beam having a half-power beam width which is one-half tha

Abstract: A transducer capable of generating a phase-encoded wavefield is described. The encoded phase is related to the angular co-ordinates of direction of transmission. By decoding the phase values of the received wavefield, a direction can be obtained. Therefore, in navigation applications this transmitter gives additional location information not available from a single received signal using traditional methods such as "range-range" and "hyperbolic" systems. In its simplest configuration, the new transducer comprises two transducers which can be individually controlled. In more complex constructions use of more than two transducers increases the controllability of the desired phase characteristics of the resulting wavefield.

Abstract: In a digital ultrasound imaging system, artifacts due to spurious ultrasound reflections from a highly reflective object outside the region of interest are reduced in magnitude by apparatus included in the beamforming system of the digital imaging system. A null is formed in a specified direction in the ultrasound beam patterns by perturbing the time delay on each receive channel. After estimating the direction of the highly reflective, interfering object and computing a time delay perturbation using a very fast algorithm, a null approximately 10 dB deep is introduced into each beam in the direction of the interfering object. This null reduces the magnitude of artifacts in the image, thereby providing image enhancement.

Abstract: A transfer device an ultrasonic sensor having an oscillating section for oscillating an ultrasonic beam toward wafers which are horizontally arranged in a carrier and a receiving section for receiving a reflected ultrasonic wave, and driving mechanism for vertically moving the ultrasonic sensor relative to the carrier so as to sequentially radiate an ultrasonic beam to the end faces of the wafers. The presence/absence of a wafer and projection of the wafer in and from the carrier are detected based on the reflected wave received by the receiving section.

Abstract: A sonar system includes an interactive sonar viewing apparatus for facilitating operator selection of a variety of features. The interactive sonar viewing apparatus can include a screen display for displaying a graphical representation of characterization data representative of the predetermined signal characteristics of each of the transducers. The characterization data can include data representative of the predetermined orientation and predetermined cone angle of each of the transducers. Based upon the graphical representation of the characterization data, the operator can select the specific transducers to be activated. Thus, the operator can selectively reconfigure the sonar system. Alternatively, the interactive sonar viewing apparatus can include a screen display which displays a graphical representation of orientation data representative of a number of display frames.

Abstract: An ultrasonic transducer is provided which has multiple apertures in at least the elevation direction, and preferably in both the elevation and azimuth direction. Each aperture has a selected focal length, with the focal length increasing with the size of the aperture. By transmitting multiple scan lines at a given angle using the different apertures and line splicing received echo signals, resolution is enhanced by utilizing only the portion of each received scan line for which the corresponding elevation aperture is focused. While different controlled elevation apertures may be utilized for transmit and receive, the same aperture is preferably used for both. Additional techniques are discussed for both further enhancing resolution and for mitigating the decrease in frame rate which results from shooting multiple scan lines at a given angle.

Abstract: A beamformer system is disclosed which includes an array of sensors such as ydrophones which produce signals from which information relating to a target is to be determined. The beamformer system includes a channel for each sensor, the channel including a varable length shift register which provides bulk delay to received signals, a FIR interpolation filter which provides vernier delay and shading. The system also includes a summation tree which adds the received signals and a sign extension/bit reversal filter to avoid authmetic overflow.

Abstract: A beam former for a ultrasonic diagnostic apparatus is arranged to have low-bit analog-to-digital converters and enables to obtain an excellent echo signal from blood flow. The beam former further includes a sample and hold circuit for sampling an echo signal of a pulse reflected from the inside of a human body. A delaying circuit serves to delay the output of the sample and hold circuit by a delay time corresponding to an integer multiple of a transmitted pulse period and is subtracted from the output of the sample and hold circuit. The subtracted output is analog-to-digital converted and is stored in a memory. The memory reads out the data asynchronously with the storage. The delaying circuit is composed of an analog-to-digital converter, a memory and a digital-to-analog converter and has a delay time corresponding to an integer multiple of the transmitted pulse period.

Abstract: A device is provided for processing an echo received by an array of N receiving elements from a target at range R ensonified by an LFM signal of bandwidth B transmitted for a duration T. The device receives each elements output f.sub.n (t) over the elements total receiving time and selects time window element outputs f'.sub.n (t), which are discrete portions of f.sub.n (t), each time window extending from an arbitrary initial time T.sub.0 to time T.sub.f and is spaced from T.sub.0 no more than T and, if there is a target within the window, an echo is received at time T.sub.n. Further the device produces element frequency difference outputs g.sub.n (t) from the frequency difference between a replica of at least a portion of the transmitted LFM signal and the time window element outputs f'.sub.n (t), the outputs g.sub.n (t) being tones with frequencies directly proportional to the time T.sub.n of the target from the time T.sub.0 so that the target range R=(c/2)(T.sub.0 +T.sub.n)+.DELTA.R.sub.

Abstract: Variations in the position of a part of a living object within the measurement space of magnetic resonance apparatus are determined by an ultrasound device in which bursts of ultrasonic waves having a frequency F.sub.US are transmitted towards the object in response to start signals generated to the repetition frequency F.sub.R, and ultrasonic waves reflected by the object are received and an analog echo signal is detected which is converted into a digital echo signal made up of a sequence of echo pulses having a repetition frequency F.sub.US. The device includes a controller for generating a time-window, for determining whether a predetermined edge of an echo pulse occurs within the time-window, and for setting the time for generating the next time-window at 1/F.sub.R -1/2F.sub.US after an echo pulse has occurred within the time-window.

Abstract: A system for producing reliable navigation data for a mobile vehicle, such as a robot, combines multiple range samples to increase the "confidence" of the algorithm in the existence of an obstacle. At higher vehicle speed, it is crucial to sample each sensor quickly and repeatedly to gather multiple samples in time to avoid a collision. Erroneous data is rejected by delaying the issuance of an ultrasonic energy pulse by a predetermined wait-period, which may be different during alternate ultrasonic firing cycles. Consecutive readings are compared, and the corresponding data is rejected if the readings differ by more than a predetermined amount. The rejection rate for the data is monitored and the operating speed of the navigation system is reduced if the data rejection rate is increased. This is useful to distinguish and eliminate noise from the data which truly represents the existence of an article in the field of operation of the vehicle.

Abstract: The objects of the present invention are achieved by temporarily suspending sonar beam transducer means at a first underwater location within sonar beam range of said scoured area; scanning a first portion of said scoured area with said sonar beam in a first substantially vertical plane that points in a first azimuth direction, so as to generate signals indicative of the range and bearing of said scanned first portion from said transducer means; and scanning at least a second different portion of said scoured area with said sonar beam in a second different substantially vertical plane that points in a second different azimuth direction, so as to generate signals indicative of the range and bearing of said scanned second portion from said transducer means. In actual practice, scanning by the sonar beam occurs in many different vertical planes and also can be done from different underwater locations.

Abstract: This switch device for detecting an object comprises a transducer for emitting and receiving ultrasonic signals to and from an object, a transmitter for driving the transducer, a receiver for receiving a signal from the transducer, a gate for detecting a short-distant object, a gate for detecting a long-distant object, and a circuit for setting the timings of the gates in accordance with the detecting ranges of the object.

Abstract: A PASS ultrasonic system performs a scan in which phase errors due to aberrations in the sound media are corrected prior to the acquisition of each beam. Phase errors are measured by cross correlating each of a set of reference beams with the desired beam to produce beam forming errors as a function of beam angle. This function is Fourier transformed to produce phase corrections that are employed by the ultrasonic system to offset the phase errors.

Abstract: The train of echoes received in an ultrasound imaging system having an array of ultrasound transducers is shaped and/or focused by first and second programmable beam focusing modules (16-24) in a dynamic receive focus mode. The elemental ultrasound echo signals from a plurality of channels connected to the elements of the transducer array are selectively attenuated and/or phased shifted according to the programs prescribed for the focus zones and combined by each module. The combined echo signals are further processed in conventional fashion (34-38). The modules operates alternately. One module is being programmed, while the other module is combining the elemental echo signals for processing. Each beam focusing module comprises a delay line (56-60) having a plurality of input taps and a cross point switch (52) selectively connecting the channels to the input taps. The module is programmed by selectively closing the individual cross points of the cross point switch. Beam shaping i.e.

Abstract: This invention relates to low transient switching apparatus, and more particularly to switching arrays of low transient switching circuits which are adapted for use to substantially continuously focus transducer channel outputs in an ultrasonic scanning system. A separate switching array is provided for each channel. Each array has a switching circuit with an output for each focusing delay line tap to which a signal on the channel may be applied. Each switching circuit provides a substantially constant D.C. current output regardless of the state of the circuit. Array outputs for each delay line tap are summed, and the summed outputs are applied as the input to the tap. The DC current inputs to all taps are maintained substantially equal, preferably at zero DC current.

Abstract: An ultrasound apparatus has a first group of transmission and reception channels that are respectively allocated to elementary transducer in the active aperture of a connectable transducer array. The central transmission location generated by a transmission channel and the reception location sampled by a reception channel coincide and lie on the allocated elementary transducer. In addition, a second group of transmission and/or reception channels is present, each being respectively simultaneously connectable to a plurality of elementary transducers via transmission and/or reception transfer stages for generating a virtual transmission and/or reception location that lies between the elementary transducers.

Abstract: A phased array acoustic transducer apparatus has a controller and an array of ultrasonic transducers mounted in a water tight housing. Also included in the water tight housing are a transmitter circuit which sends phased excitation signals to the array of ultrasonic transducers so as to generate a directed beam of acoustic energy. A receiver circuit, located in the water tight housing, processes and combines signals received by the array of ultrasonic transducers to generate an output signal. The controller sends both power and control signals via a cable to the transmitter and receiver circuits. The cable uses a simple serial data line and a clock signal line to transmit beam angle control signals, thereby minimizing the size of the cable. The controller sends transmitter gating signals over a gate signal line on the cable to enable and disable operation of the transmitter circuit, such as is required for a pulse-echo mode of operation.

Abstract: A beam former method and an apparatus therefor in an ultrasonic imaging system, in which switching of delay elements is performed by means of delay switches in a section in which no ultrasonic wave transmission/reception is performed and switching noise generated in this section is stored as a noise signal into a memory. The stored noise signal is subtracted from a reception signal which is obtained through ultrasonic wave transmission/reception and which contains switching noise superimposed thereon to thereby obtain a reception signal from which the noise has been eliminated.

Abstract: An array of sonar transmitting and receiving transducers are so physically rranged and their signal voltage so combined as to form beams pointing to various points of the compass. In this invention a signal is formed on a different conductor for each beam and the conductors are wiped in rapid succession to determine the presence of any beam signal. Since any signal may be short-lived the total sampling process must be in milliseconds. Any signal that occurs is converted to digital form and is fed into a first recirculating delay line time compression storage loop. All signals are stored in the first loop. Then the cluster of signals pertaining to one beam is read out to a second recirculating delay line time compression storage loop from when it is read out to a variable frequency super-heterodyne and displayed on a cathode ray tube.

Abstract: A method for imaging a sample with a beam of vibratory energy from an array of transducers excites the array with successive ones of a plurality M of coded excitation signal sets with each set occurring in a different one of successive excitation time intervals. Each different set has signals with a different code. An excitation beam, produced by the array, is focused into the sample at successively smaller distances, along a selected ray path from the array, during each successive excitation time interval. A reception beam is focused along the ray path at successively greater distances from a minimum distance away from the array during each successive one of a like plurality of reception time intervals, for receiving, during each reception time interval, return response signals reflected from the sample.

Abstract: A switch device is disclosed for detecting an object which comprises a transducer for emitting and receiving ultrasonic signals to and from an object, a transmitter for driving the transducer, a receiver for receiving a signal from the transducer, a gate for detecting a short-distant object, a gate for detecting a long-distant object, and a circuit for setting the timings of the gates in accordance with the detecting ranges of the object.

Abstract: A detection system forms a plurality of reception beams successively in angular directions by receiving incoming signals from various directions in a manner that the Doppler effect is produced to vary the carrier frequency of the incoming signals. The detection system displays underwater conditions on an indicator. To determine the underwater conditions, the detection system uses a plurality of ultrasonic transducers for receiving incoming signals, a plurality of preamplifiers for amplifying the reception signals produced by the ultrasonic transducers. A first coupling device which connects at least two of the ultrasonic transducers to a single preamplifier, and a matched filter for pulse-compressing reception signals produced by the ultrasonic transducers. A second coupling device successively couples the output terminals of the preamplifiers to an input terminal of the matched filter. The indicator displays output signals from the matched filter.

Abstract: A compensating beamformer which requires orders of magnitude fewer calculations that prior art methods. A compensating beamformer is provided which comprises a plurality of sensing elements and a plurality of analog-to-digital converters, for converting incoming analog signals to digital form. Digital signals from at least four such elements are used to compute phase angle information which is combined to form a matrix of input data in the frequency domain. An unweighted steering vector is determined to sample data from the target direction. A corrector matrix is calculated based on input data from sensing elements. That corrector matrix along with its inverse, which is determined recursively, is used in combination with the unweighted steering vector to determine an optimal steering vector. The input data in the frequency domain are then multiplied by the optimal steering vector to obtain signals in the directions of interest.

Abstract: In a sonar used to determine the characteristics of the underwater mines, the emission diagram in the vertical plane is modified to obtain two main lobes separated by a central zero value. At reception, the bearing/frequency display system shows a dark strip separated by two luminous strips. When the echo from a mine persists, in going through the dark zone, it is recognized that it pertains to a moored mine floating in the water, thus enabling moored mines to be identified and their submersion depth measured.

Abstract: The intensity profile of an ultrasound beam in an ultrasound imaging system is adjusted by driving the individual piezoelectric crystals with drive signals having adjustable pulse durations. The duration of the drive pulse determines the frequency spectrum of the pulse and therefore determines the amplitude of the emitted ultrasound wave. The pulse durations may be selected such as to compose a desired profile of the ultrasound beam.

Abstract: An object detecting system including an ultrasonic transducer element array including first to N-th ultrasonic transducer elements, a first means for intermittently supplying burst driving pulses to the ultrasonic transducer elements at different times in each of successive intermittent periods. Also, the object detecting system includes a second means coupled between each of the first to N-th ultrasonic transducer elements and the first means for applying the burst driving pulses to the first to N-th ultrasonic transducer elements, successively.

Abstract: A switch matrix for a transceiver of ultrasonic waves containing a configuration of electroacoustic transducer elements in which in succession proceeding over the arrangement a group of transducer elements can be activated, contains a number of inputs (K1, K2, K3, K4), the number corresponding to the number of transducer elements of a group which are each connected to one of the activated transducer elements, an equal number of outputs (R1, R2, R3, R4) connected to delay elements and a large number of switches T11, T12, . . . , T44) to establish each of the connections required for electronic focusing between the inputs and the outputs. Each input line (K1) is connected to a number of switches (T11, T12, T13, T14), this number corresponding to the number of transducer elements of a group. The switches of the switch matrix are activated through a control circuit (50) over a number of control lines (L1, L2, L3, L4), this number corresponding to the number of transducer elements of a group.

Abstract: Ultrasonic apparatus for use in detecting an object having a transducer. The transducer has an array of at least one element coupled directly into air. The apparatus also includes a transmitter which may be multi-channel, a receiver which may be multi-channel, a transmit receive switch, and a computer for causing operation of said transmit receive switch to cause sequential supplying of pulses of energy from the transmitter to the element or elements of the transducer and for receiving energy received by the transducer. The element or elements of the transducer are provided with a roughened surface to produce high frequency ultrasonic energy.

Abstract: An ultrasonic wave sensor wherein the transmitter and receiver include a linear array of transducers. Each of the transducers of the transmitter are driven by plural pulsed signals in each of a plurality of intermittent time periods. The timing of the pulsed signals to each of the transducers is controlled to produce wave fronts that interfere to produce combined wave fronts at angles to the array of transducers. Three-phase charge coupled devices in conjunction with three-phase clocking pulses are used to produce pulsed signals of predetermined delays to each of the transducers. The receiver uses three-phase charge coupled devices and three-phase clocking pulses to process returned signals.

Abstract: An apodization attenuation circuit to achieve a selected percent Gaussian apodization of a focused ultrasound wavefront when transmitted from a linear or phased array. The circuit uses a string of resistors, one resistor positioned between the drivers of each element in the transducer array. Each node of the resistor string functions as the reference potential input for one driver. Each node includes a pair of normally open switches, one of which may be closed to common and one of which may be closed to full reference potential. By closing four switches, two to common and two to full reference potential, a profile of potential of a selected percent Gaussian apodization can be achieved such that the output pulse magnitude of each transducer element in an aperture varies as a Gaussian function of its distance from the center of the aperture.

Abstract: In the ultrasonic wave phase matching diagnostic apparatus described in the specification, an array of ultrasonic transducers is arranged to transmit ultrasonic waves to an object to be investigated and to receive ultrasonic waves returned from the object. Focusing of the waves to a point in the object is accomplished by selective delaying of the transmitted signals from each of the ultrasonic transducers, and similar delays are imposed on received signals to define a focal point for signals received from the object. Scanning of the object is provided by stepwise changes in the ultrasonic transducers used for transmitting and receiving ultrasonic signals, and half-pitch scanning may be effected by using different numbers of ultrasonic transducers for transmission and reception of the ultrasonic waves.

Abstract: Phased-array apparatus has a number of ultrasonic transducer elements (E1 to E64) to which are associated delay line elements (M1, T1 to M64, T64, W1-1, W1-2, N1 to W16-1, W16-2, N16; W1 to W16; VL1 to VL64, VR1 to VR16) to provide reception. In order that the control angle may be adjusted with high accuracy, according to the inventive principles delay line elements are provided for the received signals with a short and with a long delay, and several adjacent channels are combined for signal processing. Due to this arrangement, economical constructions of embodiments of the invention are realized.

Abstract: A transmitter/receiver for suppling a pulse power to a transducer and receiving a signal from the transducer comprises a parallel connection of a first circuit including a first switch element connected in series with a power supply having one terminal thereof connected to a common potential point, a second circuit including a second switch element connected in series with a receiver having one end thereof connected to the common potential point, and a third circuit including the transducer having one end thereof connected to the common potential point.

Abstract: Ultrasound imaging apparatus having an array of electro-acoustic transducer rings, means for exciting said transducer rings in sequence so as to cause them to transmit successive pulses of pressure waves along a path at intervals at least equal to the time of transit of the pressure waves to a maximum range and back to the array, dynamically controlled delays respectively coupled to each transducer ring that bring the electrical signals the transducers supply in response to pressure of waves of each pulse that are reflected along a given range into reasonable phase coherence, processing means coupled to the delays so as to provide a composite signal, and a summing memory coupled to receive the composite signal.

Abstract: A wide dynamic range digital receiver for radar or sonar applications wherein the wide dynamic range is achieved by increasing the sampling rate of the received signals through the use of a special purpose microprogrammed digital receiver processor implemented with a plurality of processing elements especially designed for performing sum of products' computations on a pipelined basis. The processing elements utilize VHSIC technology to achieve multiplication of two 24-bit operands at nanosecond rates.

Abstract: An ultrasonic imaging processing system includes transducers and means to generate in an analog fashion, in-phase and quadrature phase signals. These signals are converted to digital form and a butterfly phase rotator circuit is employed to correct for phase differences in beam steering and focusing. In particular, speed and simplicity is achieved through the utilization of read only memory means providing appropriate function values for phase correction in conjunction with digital multiplication and summing circuitry.

Abstract: A device for electronic focusing of ultrasonic waves in which the focusing means comprise a hierarchized assembly of elementary circuits each provided with a delay line connected in parallel with a direct line to a centralizing unit and in which the time-delay of the delay line in a circuit is a function of the relative time-delay which must exist between the two cells or the two circuits connected to said circuit. It is shown that, in the invention, a technological advance is achieved by thus minimizing the maximum time-delays to be established in the case of each delay line.

Abstract: An ultrasound apparatus permitting dynamic variation of the position of the reception focus of a prescribable number of ultrasound transducer elements has a reception channel including a time-delay circuit for the received ultrasound echo signal following every ultrasound transducer element. For switching between different, prescribed time-delay values (T.sub.1, T.sub.2, . . . T.sub.n), the time-delay circuit is connected to a control device. A part of the time-delay circuit is redundantly designed, so that first and a second sub-circuits for forming the time-delayed ultrasound echo signal are present. A dissolve circuit is provided which causes the second sub-circuit to be faded in the reception channel when the first sub-circuit, in a blanked condition, is switched to a different time-delay value (T.sub.1, T.sub.2, . . . T.sub.n), and vice versa, by a control device. Significant time is thus saved when switching between the different focus positions of the ultrasound apparatus.

Abstract: An ultrasonic distance sensing method and apparatus are disclosed in which a transducer periodically transmits a pair of bursts of acoustic energy along an acoustic path toward a target object, an echo of the first acoustic burst in each burst pair is used to establish a peak reference level, and an echo of the second burst in each pair is used to determine distance to the target object only if its level exceeds a predetermined fraction of the peak reference level.

Abstract: A plurality of ultrasonic transmitting elements and ultrasonic receiving elements are provided and are electrically switched in a sequential manner to change a region over which the existence of an object is to be detected, thus allowing the existence of an object to be detected over an extended range. The distance to the object and a particular region in which it is detected are displayed. The ultrasonic transmitting elements and the ultrasonic receiving elements are alternately disposed in a linear array. When switching the region over which the existence of an object is to be detected, the switching of the ultrasonic transmitting elements takes place in an alternate fashion with the switching of the ultrasonic receiving elements, thus changing the region at an interval corresponding to one pitch with which the elements are disposed in the array.

Abstract: An obstacle detection system has a sensor unit including a plurality of ultrasonic transducers and sequentially changes the number of pulses provided to groups of transducers, thereby performing front center sensing, front right sensing and front left sensing. The time between emission of ultrasonic waves and reception of waves reflected by an obstacle is calculated by a timer. A microcomputer computes the distance data and position data of the obstacle in accordance with obtained timer data and sensing region data.

Abstract: In the scanning type ultrasonic equipment provided with a probe a plurality of transducer elements and with a phasing circuit for signals which are delivered from the transducer elements on the basis of a received ultrasonic wave, the phasing circuit includes constant current circuits each for converting selected ones of the signals from the transducer elements into a constant current signal, and a delay line having taps which are connected to the constant current circuits, in order to reduce the number of parts included in the phasing circuit and the number of adjusting operations performed therein.