Abstract: The present disclosure provides an acoustic wave transducer and a driving method thereof. The acoustic wave transducer includes cell groups, at least part of which each include acoustic wave transducer cells configured to perform a same operation, each acoustic wave transducer cell being configured to perform at least one of: converting an acoustic wave signal into an electrical signal and converting an electrical signal into an acoustic wave signal; and array element signal terminals, each of which is coupled to at least two adjacent cell groups, and is coupled to different cell groups through different switch devices, each switch device being configured to control connection and disconnection between the array element signal terminal and the cell group coupled to the switch device, and the cell groups coupled to an array element signal terminal and the cell groups coupled to an adjacent array element signal terminal are partly the same.

Abstract: A system, method, and device for monitoring one or more sensors at a remote location. The system allows a user to register multiple sensors to the user's account. When the sensors are deployed at a remote location for measuring various properties of their surrounding environments, they collect data which is then transmitted to a server. The user may then monitor the data by connecting to the server via a client device, and receive alerts when the data satisfies certain conditions.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) may be configured to be positioned in different possible physical configurations and may identify its current physical configuration based on a modem-based sensor. The UE may transmit a signal from a first antenna element and receive an echo of the signal at a second antenna element different than the first antenna element. The UE may then generate an echo signature for the echo of the signal and determine that the UE is in a first physical configuration (e.g., its current physical configuration) from the possible physical configurations by comparing the generated echo signature to a set of echo signatures that correspond to each of the possible physical configurations. Accordingly, based on the determined first physical configuration, the UE may perform an operating system function that corresponds to the first physical configuration.

Abstract: Apparatuses and methods for electrohydraulic generation of Shockwaves at a rate of between 10 Hz and 5 MHz, and/or that permit a user to view a region of a patient comprising target cells during application of generated Shockwaves to the region. Methods of applying electro-hydraulically generated Shockwaves to target tissues (e.g., for reducing the appearance of tattoos, treatment or reduction of certain conditions and/or maladies).

Abstract: Apparatuses and methods for electrohydraulic generation of shockwaves at a rate of between 10 Hz and 5 MHz, and/or that permit a user to view a region of a patient comprising target cells during application of generated shockwaves to the region. Methods of applying electro-hydraulically generated shockwaves to target tissues (e.g., for reducing the appearance of tattoos, treatment or reduction of certain conditions and/or maladies).

Abstract: Micromachined ultrasonic transducer (MUT) arrays capable of multiple resonant modes and techniques for operating them are described, for example to achieve both high frequency and low frequency operation in a same device. In embodiments, various sizes of piezoelectric membranes are fabricated for tuning resonance frequency across the membranes. The variously sized piezoelectric membranes are gradually transitioned across a length of the substrate to mitigate destructive interference between membranes oscillating in different modes and frequencies.

Abstract: Various techniques are described that relate to the manner in which marine devices may generate and display a water depth contour map while navigating a body of water. The contour map includes contour lines associated with determined contour line data that indicate geolocations of underwater terrain existing at depths of the body of water specified by the contour lines. A boundary enclosing a region of interest for the body of water may be determined and the contour map may include contour lines determined using the determined contour line data within the region of interest. The boundary may correspond to a natural shoreline along the perimeter of a body of water or a portion of the body of the water. The boundary corresponding to a shoreline may be automatically identified based on a stored map by identifying geographic locations along the perimeter of the body of water.

Abstract: Methods and systems for storing and processing a plurality of fractions of imaging data thereby minimizing the amount of cache memory necessary while controlling data loss and the resulting image quality.

Abstract: A capacitive micromachined ultrasonic transducer (CMUT) having at least two deflectable membranes. The membranes are spaced from each other, and the membranes contribute to and/or are responsive to receive or transmit an ultrasonic signal. Spacing between the at least two deflectable membranes is adjustable through application of a voltage to cause deflection of at least one of the deflectable membranes, to affect the receive/transmit properties of the CMUT.

Abstract: A method and system for determining a velocity of a moving object such as a body or a stream. The object is irradiated in a non-collinear configuration with multiple ultrasound waves overlapping in a region-of-interest (ROI) of the object. An response wave, resulting from the non-linear interaction among the incident waves and the object, is detected and the frequency variations of the response wave are determined. Data representing a Doppler-shift of this frequency is further determined and processed to calculate the velocity of the moving object.

Abstract: An apparatus for determining location of a moveable object in relation to an input device includes an array of one or more piezoelectric micromachined ultrasonic transducer (pMUT) elements and a processor. The array is formed from a common substrate. The one or more pMUT elements include one or more transmitters and one or more receivers. The processor configured to determine a location of a moveable object in relation to an input device using sound waves that are emitted from the one or more transmitters, reflected from the moveable object, and received by the one or more receivers.

Abstract: A first controller can have a greater number of output lines than a second controller has input lines. The first controller can receive an ultrasonic transducer control signal and provide a first portion of the control signal to the first processor, where the length of the first portion is less than or equal to the number of input lines of the second processor. The first processor can send portions of the control signal to a plurality of second processors. Each of the plurality of second processors can have a number of input lines less than the number of output lines of the first processor. Portions of the control signal can be sent through the output lines of the first processor to the plurality of second processors at substantially the same time.

Abstract: A sonar system is provided with the system having comparatively reduced power consumption, data bandwidth and data storage requirements. A sensor array of the system is configured to a sleep mode, low-resolution mode and high-resolution mode. In the sleep mode, all sonar sensors are configured in the mode and no acoustic signals are detected or processed. In the low-resolution mode, a limited number of sonar sensors are powered and acoustic signals received by the sensors are processed with reduced bandwidth and dynamic range, and then stored on a data storage device. In the high-resolution mode, the acoustic signals detected by the sonar sensors are processed with full signal bandwidth and dynamic range and then stored on the data storage device. A 10 bit mu-Law encoding scheme is used to reduce the amplitude scale of measurement or dynamic range of the digitized acoustic signals.

Abstract: A transducer for sub-ocean bottom imaging includes: a housing capable of withstanding hydrostatic pressure of about 9,000 pounds per square inch; a transmitting layer positioned within the housing to transmit two primary high frequency transmit beams that generate a low frequency signal whose frequency is an arithmetic difference between the two primary beams for high resolution sub-ocean bottom imaging while maintaining high spatial resolution or directivity; and a receiving layer collocated with the transmitting layer within the housing that is mechanically tuned to resonate at the difference frequency producing high receive sensitivity.

Abstract: An apparatus comprises a test signal generator (401) which generates an ultrasonic test signal by modulating an audio band test signal on an ultrasonic signal. The ultrasonic test signal is radiated from a parametric loudspeaker (403) and is demodulated by non-linearities in the air. A reflected audio signal may arise from reflections of an object, such as a wall. An audio band sensor (405) generates an audio band captured signal which comprises the demodulated reflected audio band signal. A distance circuit (407) then generates a distance estimate for the distance from the parametric loudspeaker (403) to the object in response to a comparison of the audio band captured signal and the audio band test signal. Specifically two signals may be correlated to determine a delay corresponding to the full path length. Based on the distance estimates an audio environment may be estimated and a sound system may be adapted accordingly.

Abstract: A method includes identifying a ping forecast time window given a current set of target tracks to hold, discretizing the ping forecast time window with more than one potential ping time, calculating, given more than one ping source and ping waveform, a ping control metric for each combination of potential ping time, ping source, and ping waveform, and creating a ping command using the maximum calculated ping control metric. The ping command includes a specific ping source from the more than one ping source, a specific ping waveform from the more than one ping waveform, and a specific ping time from the more than one potential ping time. The ping control metric may be a user-defined metric that is a function of predicted signal-to-noise ratios and predicted target tracks, and may contain aspect dependent target strength and target position and velocity data for a particular potential ping time.

Abstract: A method, which allows, in an acoustic pulse-echo ranging system, the direct use of a digitized raw echo signal for correlation-based echo distance estimation, where an acoustic pulse having a carrier frequency is transmitted, a digital expected echo shape is provided with a time resolution higher than the carrier frequency, an echo is received from the acoustic pulse, the received echo is sampled and digitized at a sampling frequency higher than the carrier frequency, correlation values are created from the digitized received echo and the digital expected echo shape, the correlation values are weighted by emphasizing stronger correlation values, and the echo distance is determined from the center of mass of the weighted values.

Abstract: An acoustic transducer has a first transducer which transmits an acoustic primary wave having two frequency components, and a second transducer which, in order to receive a reflected wave of an acoustic secondary wave generated with propagation of the acoustic primary wave, is disposed so that a region for receiving the reflected wave is superimposed on the first transducer as seen along the direction of transmission of the acoustic primary wave.

Abstract: Provided is a measuring apparatus, including: a moving mechanism for moving a probe in an elevation direction; a first delay and sum circuit for performing delay and sum of reception signals at individual positions along the elevation direction to output a first add signal; a signal extraction circuit for letting an output of the first delay and sum circuit to pass through delay circuits to output in parallel first add signals obtained at different positions; a second delay and sum circuit for performing delay and sum of the first add signals output from the signal extraction circuit to output a second add signal; and an image processing circuit for generating image data by using the second add signal. Accordingly, image resolution in the elevation direction may be improved with a simple structure without deteriorating an image obtaining speed in the measuring apparatus for obtaining an ultrasonic image.

Abstract: A guiding device controls the directivity of a sound that is reproduced from a speaker in accordance with an attribute of contents.

Abstract: A method and apparatus for generating a seismic source signal are provided for generating energy in the form of a plurality of time sequence vibratory signals, the vibratory signals being partitioned as a function of time and/or frequency, wherein each of the plurality of signals comprises a distinguishing signature.

Abstract: An imaging system comprises a device to excite mechanical waves in elastic tissue, a device for measuring the resulting tissue motion at a plurality of locations interior to the tissue at a number of time instances, a computing device to calculate the mechanical properties of tissue from the measurements, and a display to show the properties according to their location. A parameter identification method for calculating the mechanical properties is based on fitting a lumped dynamic parametric model of the tissue dynamics to their measurements. Alternatively, the mechanical properties are calculated from transfer functions computed from measurements at adjacent locations in the tissue. The excitation can be produced by mechanical vibrators, medical needles or structures supporting the patient. The measurements may be performed by a conventional ultrasound imaging system and the resulting properties displayed as semi-transparent overlays on the ultrasound images.

Abstract: A sonar imaging system for a watercraft is disclosed. The sonar imaging system comprises a transducer coupled to the watercraft and having at least one side scanning element and at least one bottom scanning element, an electronic control head unit coupled to the transducer and configured to display sonar images. The downward acoustic elements may be circular and the side scan acoustic elements may be rectangular. A software filter may be provided to remove noise generated by a spark plug or other operation of a motor for the watercraft.

Abstract: A multiple resonances type ultrasonic transducer for a ranging measurement with high directionality using a parametric transmitting array in air, includes an ultrasonic actuator unit formed with a regularly mixing array of first unit actuators having a resonance frequency of f1 and second unit actuators having a resonance frequency of f2. The ultrasonic actuator unit generates a difference frequency wave (fd=f1?f2) with high directionality by forming a parametric transmitting array in air through generating two ultrasonic waves with high pressure in air. Further, the transducer includes an ultrasonic sensor unit formed with one or more unit sensors having a resonance frequency of the difference frequency (fd=f1?f2), for sensing a reflected ultrasonic pulse signal from a target.

Abstract: A multiple resonances type ultrasonic transducer for a ranging measurement with high directionality using a parametric transmitting array in air, includes an ultrasonic actuator unit formed with a regularly mixing array of first unit actuators having a resonance frequency of f1 and second unit actuators having a resonance frequency of f2. The ultrasonic actuator unit generates a difference frequency wave (fd=f1?f2) with high directionality by forming a parametric transmitting array in air through generating two ultrasonic waves with high pressure in air. Further, the transducer includes an ultrasonic sensor unit formed with one or more unit sensors having a resonance frequency of the difference frequency (fd=f1?f2), for sensing a reflected ultrasonic pulse'signal from a target.

Abstract: The present invention is directed towards an acoustic concealed item detector and related methods for detection using acoustics. In an illustrative embodiment, a multi-frequency ultrasonic wave generator generates in a gaseous medium at least first and second ultrasonic waves. The multi-frequency ultrasonic wave generator is arranged such that in operation, the first ultrasonic wave and the second ultrasonic wave mix in a prescribed mixing zone to produce a difference-frequency acoustic wave. A receiver sensor detects the difference-frequency acoustic wave and produces corresponding electromagnetic signals. The electromagnetic signals are processed by a system processor and signals indicative of concealed items are identified. Preferably the ultrasonic waves are focused to a small prescribed mixing zone. Parametric and multi-transducer embodiments are disclosed.

Abstract: The present invention is directed to a sonar system that includes a transmitter configured to direct multi-frequency transmit signals into a propagation channel. Each multi-frequency transmit signal includes a first frequency and a second frequency. A receiver is tuned to receive multi-frequency return signals propagating in the propagation channel. Each multi-frequency return signal includes a first frequency return signal and a second frequency return signal. The first frequency return signal has a first phase and the second frequency return signal having a second phase. A signal processor is coupled to the receiver. The signal processor is configured to extract the first phase and the second phase from the multi-frequency return signal and calculate a phase difference. The phase difference is the difference between the first phase and the second phase.

Abstract: An ultrasonic ranging method for measuring a distance to an object in an air includes the steps of generating a first and a second primary ultrasonic waves having a frequency f1 and f2, respectively, transmitting the first and the second primary ultrasonic waves in a same direction, wherein a secondary ultrasonic wave having a frequency corresponding to the difference of two frequencies fd=f1?f2 is created by a nonlinear property of the air and radiated to the object, detecting an echo pulse of the secondary ultrasonic wave reflected from the object, and measuring the distance to the object based on a propagation time of the secondary wave.

Abstract: Apparatus is disclosed for steering a directional audio beam that is self-demodulated from an ultrasound carrier. The apparatus includes means for modulating a carrier signal with an audio signal and means for adjusting the amplitude and phase of at least one of the audio signal and/or the carrier signal to steer the audio beam to a desired direction. The apparatus also includes means for generating an ultrasound beam in the desired direction driven by the modulated carrier signal. The apparatus may include means for weighting the audio and/or carrier signal by a zeroth order Bessel function to synthesize a Bessel distribution source. A corresponding method for steering a directional audio beam is also disclosed. A harmonic generator may be used to generate harmonics of low frequencies in the audio signal. The harmonics may provide (upon demodulation) a psycho-acoustic impression of improved perception of low frequencies.

Abstract: The invention is directed to a system and method for detecting defects in a manufactured object. These defects may include flaws, delaminations, voids, fractures, fissures, or cracks, among others. The system utilizes an ultrasound measurement system, a signal analyzer and an expected result. The signal analyzer compares the signal from the measurement system to the expected result. The analysis may detect a defect or measure an attribute of the manufactured object. Further, the analysis may be displayed or represented. In addition, the expected result may be generated from a model such as a wave propagation model. One embodiment of the invention is a laser ultrasound detection system in which a laser is used to generate an ultrasonic signal. The signal analyzer compares the measured ultrasonic signal to an expected result. This expected result is generated from a wave propagation model. The analysis is then displayed on a monitor.

Abstract: A parametric sonar for use in a liquid medium includes a first signal generator which transmits a first acoustic signal and a second signal generator transmitting a second acoustic signal which interatct to produce a difference frequency signal at an interference region. A cavitation generator is provided to transmit a cavitation acoustic wave causing cavitation vapor bubbles in the liquid medium at the interference region. The cavitation vapor bubbles improve the efficiency of generating the difference frequency signal.

Abstract: A piezoelectric embedded monolithic active surface for transmitting a directed acoustic beam comprising a monolithic active surface, a plurality of piezoelectric elements embedded on the surface forming an array comprising, a plurality of coupled frequency pairs comprising, a first primary frequency row extending in a frequency steered direction the first primary frequency row enabled to accept a first primary frequency signal, and a second primary frequency row extending in the frequency steered direction and located adjacent to the first primary frequency row the second primary frequency row enabled to accept a second primary frequency signal, wherein the plurality of coupled frequency pairs repeat in a delay-steered direction and wherein each of the coupled frequency pairs are enabled to accept a time delayed copy of the first and second primary frequency signals.

Abstract: A piezoelectric embedded monolithic active surface for transmitting a directed acoustic beam comprising a monolithic active surface, a plurality of piezoelectric elements embedded on the surface forming an array comprising, a plurality of coupled frequency pairs comprising, a first primary frequency row extending in a frequency steered direction the first primary frequency row enabled to accept a first primary frequency signal, and a second primary frequency row extending in the frequency steered direction and located adjacent to the first primary frequency row the second primary frequency row enabled to accept a second primary frequency signal, wherein the plurality of coupled frequency pairs repeat in a delay-steered direction and wherein each of the coupled frequency pairs are enabled to accept a time delayed copy of the first and second primary frequency signals.

Abstract: The invention concerns a warning system to help preventing drowning accidents. The system comprises at least a sonar (1). Each sonar (1) comprises at least a transmission antenna and a reception antenna having transmission (4) and reception (5) apertures. The sonar (1) is a parametric sonar with high spatial directive gain along said transmission (4) and/or reception (5) apertures. The angular opening of the transmission (17) and/or reception (18) lobes of said transmission and/or reception antennae is of the order of one degree or less than one degree. The system comprises a processing calculator. The sonar (1) comprises amplifier means and transmission means for amplifying and transmitting the electric signals coming from said reception antenna.

Abstract: Vibrator comprising a single vibration generator coupled with the medium by a coupling element and means for controlling the generator, suited to apply thereto, on each emission, a single pilot signal obtained by combination of at least two signals of different frequencies (f1, f2), fixed or preferably variable within at least partly separate frequency bands, and non-linear elastic transmission means suited to generate in the medium vibrations at a frequency depending on the frequency difference of the two vibrational signals. The exploration method comprises using the vibrator in order to emit very low-frequency vibrations in the medium reception by pickups (R) of the waves reflected by the medium in response to the vibrations emitted and recording thereof, and selection by correlation of the vibrational signals with a synthetic signal whose frequency is connected with the frequency difference of the signals forming the pilot signal.

Abstract: A force is produced within an object by two intersecting ultrasonic beams. The frequency of this force is equal to the beat frequency of the two intersecting beams when their frequencies are made different, or the force may vary as a function of a baseband audio signal f(t) that is used to modulate one of the two beams. The sonic waves produced at the intersection of the two beams can be used to detect the presence of objects or to image objects based on their mechanical properties, or to regenerate desired audio signals at the intersection.

Abstract: Active sonar apparatus, especially adapted for detecting submarine targets under ice, includes means for providing first and second pulsed, underwater acoustic signals respectfully having a high frequency, f.sub.H, and a low frequency, f.sub.L. The high frequency, f.sub.H, is selected for causing the signal to be reflected at the submerged, water-ice interface and and the low frequency, f.sub.L, selected for enabling the signal to be propagated through the ice with no significant reflection at the water-ice interface while then causing the signal to be reflected at the above-water, air-ice interface. Included are means for separately receiving and processing the reflected signals from the first and second acoustic signals and for detecting possible target reflections (which may include ice reflections) as a function of range and angle cells.

Abstract: A ground-penetrating sonar echo locating device uses acoustic energy to locate underground structures, such as piping. A transducer, driven with two frequencies whose amplitudes would be rapidly attenuated in surface or through-the-ground transmission, is directed toward the ground through a silastic waveguide having a non-linear characteristic that produces a narrow beam of acoustic energy having neglible side lobes at a third frequency that is relatively unattenuated in ground transmission to produce reflections indicative of sub-soil conditions.

Abstract: A sonar system has at least two separated bottom-mounted acoustic modules, each module including a projector for generating horizontal sound beam, a vertical line receive array for monostatic and bistatic detection, and a high frequency, upward-directed transducer for providing a steerable vertical beam to ensure full water column coverage by the use of surface reflections to minimize shadowing caused by high relief bottom topography.

Abstract: A platform borne sonar system for the detection of targets includes a transmitting projector suspended beneath the water surface from a platform for generating a virtual parametric acoustic array in a water column, forming a beam of acoustic energy. The beam is scannable in azimuth to steer the direct beam in particular directions. A plurality of detectors are arranged to receive the acoustic energy scattered or reflected from any submerged objects present in said direct beam, wherein one or more of the detectors are located the of said direct beam for bistatic reception of the beam reflected off the target. A detector may be suspended beneath the projector for monostatic reception. The direct beam may be scannable in elevation. The direct beam may be narrower vertically than horizontally.

Abstract: A sonar system for use in a water body includes a projector on the bottom of a water body for generating and transmitting a direct beam of acoustic energy. A receiving array is immersed in the water body outside the direct beam for detecting reflections from an target in the direct beam. The receiving array may be a horizontal or vertical linear array of hydrophones in the water body. The array of hydrophones may have output signals coupled to an A/D convertor and a multiplexor for digitizing and multiplexing the signals to prepare for transmission and analysis of the signals. A pair of separated projectors on the bottom of the water body may generate parametric acoustic arrays for transmitting direct beams of acoustic energy through the water body towards each other. A receiving array immersed in the water body outside the direct beams detect any reflections from an object in the acoustic beams.

Abstract: A positionable transducer array on a stationary platform proximate a layered site on the seabed coherently insonifies locations at the site with a signal having a selected power, resultant center frequency, beamwidth, bandwidth, shape and incident angle. A positionable receiver array on the platform captures the return signals. Sub-surface acoustical properties of the location are then predicted from the return signals and a calculation of the speed of sound in water at the site. Subsequent locations at the site are then interrogated and an interpolation is made of acoustical properties between locations to develop a model of the acoustical properties at the site.

Abstract: This invention relates to a parametric source Doppler acoustic wind profiler for measuring atmospheric wind conditions. It includes a parametric acoustic source excited by a transmitter generating a pair of primary frequencies and radiates an intermodulation difference frequency. Echoes of the difference frequency are produced by wind induced scatter at the difference frequency which is significantly lower than the transmitted primary frequencies and detected by a single microphone or an array of microphones.

Abstract: A self-guidance system for submarine vehicles containing a parametric sonar including preformed channel, transmission device and, in each channel, two beams at the primary frequencies formed simultaneously. Reception takes place with preformed beams at the primary and the secondary frequencies followed by a filter giving frequential channels. An echo comparator receives the signals at the primary and secondary frequencies and enables interference echoes from decoys in particular to be eliminated and the rudders to be controlled.

Abstract: The invention concerns an application of linear system parameter estimation techniques to finite amplitude sonar devices, to extract fine grained angular position information about echo sources. The invention makes use of the fact that the waveform return by a reflecting object within the sonar's beam varies according to its relative angular position from the receiver, and a discovery that this variation may be fit to a linear system model using autoregressive estimation theory to extract the nature of the variation. In all cases, the information is extracted without the mechanical or electrical steering of the sonar transmitting beam.

Abstract: Sonar ice thickness measurement comprises transmitting an AM and subsequent CW sonic radiant energy signals from the water toward the sonic signal reflecting ice cap. Reflection of the CW signal from the water-ice interface and reflection from the water-air interface of the modulating frequency, generated by non-linear or parametric effects in the water by the modulated transmit signal, causes the CW signal to be modulated to generate side bands at the modulating frequency on each side of the carrier frequency to provide an FM high frequency signal. Detection of the FM signal determines the time of arrival of the echo of said detected FM signal relative to the detection of the reflected modulated signal from the water-ice interface.

Abstract: A method for synthesizing arbitrary broadband signals for a parametric ar which computes the input waveform needed to a parametric array source to obtain a received signal of a prescribed waveform. The method uses Fourier transform and the inverse transform of digitized received signal in order to make computation in either the frequency domain or the time domain depending upon the computational simplicity in a particular domain. The method uses a iterative process to obtain the received signal very close to the received signal of the desired waveform.

Abstract: An interferometric sonar in non-linear acoustics for high-resolution observations of objects located in the vicinity of the sea floor includes two end transducers for simultaneous transmission at two high frequencies F.sub.1 and F.sub.2 of the order of 200 kHz. Reception is performed by hydrophones placed between the sending transducers at the low frequency F.sub.2 -F.sub.1 of the order of 20 kHz. Angular channels are formed during two transmission sequences. Transmission takes place in phase at the frequency F.sub.2 -F.sub.1 in one sequence and in phase opposition in the other sequence in the case of the two sources generated by non-linear effects.

Abstract: A sonar system comprises a vehicle (1) capable of moving over the bottom of an extent of water, with an emitter of acoustic pulses and a receiver of acoustic energy mounted on said vehicle. Signal processing and display circuitry (e.g. on board a surface vessel 2) are connected to receive signals representative of the acoustic waves emitted by the emitter, of the acoustic waves received by the receiver, and of parameters describing the motion of the vehicle. The signal processing and display circuitry generates an image of objects hidden in the water bottom on the basis of the signals. The emitter of acoustic pulses is provided with at least one parametric transducer having a spot radiation pattern capable of forming a plurality of channels that bathe spots of the water bottom in sound waves, and an electronic pointing system for scanning the channels.

Abstract: A sonic energy scanning apparatus in which two directional primary sonic energy beams at two different frequencies are radiated into a medium capable of producing nonlinear acoustic effects to produce a third sonic energy beam having a given directional characteristic and a frequency equal to the difference between the frequencies of the primary beams. Scanning with the third beam is effected by varying the direction of the axes of, and the frequency difference between, the two primary beams in discrete steps for correspondingly varying the direction of the axis of the third beam over a selected angular sector and the frequency of the third beam such that each direction of the third beam axis is associated with a respectively different frequency, and by identifying the direction to a source of echoes of the third beam by determining the frequency of such echoes.