Abstract: A transducer assembly includes an ultrasonic transducer element having an acoustic radiative surface and configured to emit acoustic radiation over a drive frequency range with a center frequency fc, along a normal to the surface. The assembly also includes a divergent acoustic lens acoustically coupled to the surface at a proximal surface of the lens. The lens receives the radiation at the proximal surface and transmits it through a distal surface. The lens is characterized by a maximum height h, measured from the proximal surface to the distal surface in the direction of the normal, where ¾?c?h?2?c and ?c=clens/fc, where clens is a longitudinal sound speed of the center frequency fc. Alternatively or in addition, the acoustic lens may have an acoustic impedance in a range from 1.0 MegaRayls (MRayls) to 2.0 MRayls at fc.

Abstract: A method of optimizing acoustic transducer performance, and corresponding system, can include mechanically coupling a transducer to a fluid barrier, calibrating the acoustic transducer by measuring response as a function of drive frequency to determine one or more optimum drive frequencies, optimized for the transducer actually coupled to the fluid barrier, and storing the one or more optimum drive frequencies for use in operating the acoustic transducer. Shims may also be used between the transducer and fluid barrier, such as a boat hull, to optimize transducer performance. Embodiments can enable improved in-hull transducer depth sounding, as well as improved fluid level measurements in tanks.

Abstract: In some embodiments, the methods (and systems) may generate, from the aft direction of a marine vessel, one or more pulses of sound. The methods (and systems) may receive, at the aft direction of a marine vessel, one or more echoes, in response to the generated one or more pulses of sound interacting with one or more physical objects. The methods (and systems) may perform an analysis on the received one or more echoes based upon the generated one or more pulses of sound. The analysis may be performed based upon space-time Doppler filtering. The physical objects may include game fish. The analysis may be based upon the size and/or location of atleast one of the one or more physical objects. The analysis may include acoustic detection, localizing, tracking, and/or sizing of at least one of the one or more physical objects.

Abstract: In an embodiment, an acoustic transducer includes an element with an acoustic radiative surface having two warped edges at opposing sides. In another embodiment, an acoustic transducer includes first and second elements, each divided into at least two spatially separated portions electrically coupled to each other, the portions configured to interleave. In a further embodiment, an acoustic transducer includes first and second transducer elements. The second element is situated adjacent to the first element and includes a radiative surface with an edge having periodic elongations. In yet another embodiment, an acoustic transducer includes a transducer element with an acoustic radiative surface that has a skewed diamond shape.

Abstract: A method of optimizing acoustic transducer performance, and corresponding system, can include mechanically coupling a transducer to a fluid barrier, calibrating the acoustic transducer by measuring response as a function of drive frequency to determine one or more optimum drive frequencies, optimized for the transducer actually coupled to the fluid barrier, and storing the one or more optimum drive frequencies for use in operating the acoustic transducer. Shims may also be used between the transducer and fluid barrier, such as a boat hull, to optimize transducer performance. Embodiments can enable improved in-hull transducer depth sounding, as well as improved fluid level measurements in tanks.

Abstract: In an embodiment, an acoustic projector includes an acoustic transmit transducer capable of producing a sound pressure radiation in response to a driver signal received from a transmit source, an acoustic receive transducer capable of producing a source level signal in response to receiving at least a portion of the sound pressure radiation, and a controller configured to monitor the source level signal and report the source level signal monitored.

Abstract: In an embodiment, an acoustic projector includes an acoustic transmit transducer capable of producing a sound pressure radiation in response to a driver signal received from a transmit source, an acoustic receive transducer capable of producing a source level signal in response to receiving at least a portion of the sound pressure radiation, and a controller configured to monitor the source level signal and report the source level signal monitored.

Abstract: Embodiments relate to a speed sensor and a speed sensing method for measuring relative speeds of receivers with respect to particles in a fluid by detecting individual particles. A receiver generates a plurality of signals related to reflections from particles in a region being monitored. A sampling circuit samples the signals, and a processing device processes the signals according to a particle detection scheme to determine speed. Concomitant use of the same receivers allows depth measurement.

Abstract: Embodiments relate to a speed sensor and a speed sensing method for measuring relative speeds of receivers with respect to particles in a fluid by detecting individual particles. A receiver generates a plurality of signals related to reflections from particles in a region being monitored. A sampling circuit samples the signals, and a processing device processes the signals according to a particle detection scheme to determine speed. Concomitant use of the same receivers allows depth measurement.

Abstract: In an embodiment, an acoustic transducer includes an element with an acoustic radiative surface having two warped edges at opposing sides. In another embodiment, an acoustic transducer includes first and second elements, each divided into at least two spatially separated portions electrically coupled to each other, the portions configured to interleave. In a further embodiment, an acoustic transducer includes first and second transducer elements. The second element is situated adjacent to the first element and includes a radiative surface with an edge having periodic elongations. In yet another embodiment, an acoustic transducer includes a transducer element with an acoustic radiative surface that has a skewed diamond shape.

Abstract: An acoustic transducer for producing sonar waves features a piezoelectric structure with a radiating surface. A plurality of elements is attached to the radiating surface, and at least two of the plurality of elements have different acoustic properties. The acoustic transducer is designed for a wider beam angle for a thickness vibration mode while maintaining other desired vibration frequencies, maximum input power and low cost.

Abstract: In an embodiment, an acoustic projector includes an acoustic transmit transducer capable of producing a sound pressure radiation in response to a driver signal received from a transmit source, an acoustic receive transducer capable of producing a source level signal in response to receiving at least a portion of the sound pressure radiation, and a controller configured to monitor the source level signal and report the source level signal monitored.

Abstract: Embodiments relate to a speed sensor and a speed sensing method for measuring relative speeds of receivers with respect to particles in a fluid by detecting individual particles. A receiver generates a plurality of signals related to reflections from particles in a region being monitored. A sampling circuit samples the signals, and a processing device processes the signals according to a particle detection scheme to determine speed. Concomitant use of the same receivers allows depth measurement.

Abstract: Embodiments relate to a speed sensor and a speed sensing method for measuring relative speeds of receivers with respect to particles in a fluid by detecting individual particles. A receiver generates a plurality of signals related to reflections from particles in a region being monitored. A sampling circuit samples the signals, and a processing device processes the signals according to a particle detection scheme to determine speed. Concomitant use of the same receivers allows depth measurement.

Abstract: Embodiments relate to monitoring the temperature of a transducer and controlling the temperature as a function of adjusting one or more characteristics of the transducer.

Abstract: An acoustic transducer for producing sonar waves features a piezoelectric structure with a radiating surface. A plurality of elements is attached to the radiating surface, and at least two of the plurality of elements have different acoustic properties. The acoustic transducer is designed for a wider beam angle for a thickness vibration mode while maintaining other desired vibration frequencies, maximum input power and low cost.

Abstract: In one embodiment a method and corresponding apparatus are arranged to determine an accurate device heading by continuously combining an average magnetic heading with the compensated inertial heading. The example embodiment obtains the compensated inertial heading by compensating for a time delay of an inertial heading.

Abstract: Embodiments relate to monitoring the temperature of a transducer and controlling the temperature as a function of adjusting one or more characteristics of the transducer.

Abstract: In one embodiment a method and corresponding apparatus are arranged to determine an accurate device heading by continuously combining an average magnetic heading with the compensated inertial heading. The example embodiment obtains the compensated inertial heading by compensating for a time delay of an inertial heading.

Abstract: An ultrasound hyperthermia applicator suitable for medical hyperthermia treatment, and method for using the same, includes two ultrasound sources producing focused ultrasound beams of frequencies f.sub.0 and f.sub.1. An aiming device directs the two ultrasound beams so that they cross each other confocally at the target. A controller activates the two ultrasound sources so that the target is simultaneously irradiated by the two focused ultrasound beams. The two ultrasound sources provide acoustic energy sufficient to cause significant intermodulation products to be produced at the target due to the interaction of the two ultrasound beams. The intermodulation products are absorbed by the target to enhance heating of the target. In preferred embodiments the ultrasound sources include pair of signal generator for producing gated ultrasound output signals driving single crystal ultrasound transducers.