A transducer for non-invasive measurement includes: a piezoelectric element; a base plate; and driver electronics. The piezoelectric element is mounted to a first face of the base plate. A second face of the base plate is mountable to a wall of a vessel that holds a liquid. The driver electronics drive the piezoelectric element at a plurality of activation frequencies. When the second face of the base plate is mounted to the wall of the vessel, the transducer when activated excites acoustic waves in the base plate and to launch an acoustic wave into the liquid. The transducer is designed such that an angular divergence of the acoustic wave launched into the liquid varies as a function of at least the activation frequency and a dimension of an emitter.

Sonar systems and related methods are provided. A sonar system for generating one or more sonar images includes first and second transducer elements each having at least one emitting face. The sonar system also includes a sonar signal processor in electronic communication with the first and second transducer elements to cause transmission of signals from the first and second transducer elements to cause at least one first acoustic beam to be emitted from the first emitting face in a first beam direction and at least one second acoustic beam to be emitted from the second emitting face in a second beam direction. The first and second transducer elements are positioned such that a gap is formed therebetween. The gap is configured to facilitate movement of a fluid therein so as to contribute to an emission of sound power in both the first beam direction and the second beam direction.

An acoustic transducer (30), comprising: a support structure (36); an active assembly comprising a base plate (32) supported by the support structure (36) and a piezoelectric body (34) supported by the base plate (32); and a passive vibrator (38) supported by the support structure (36) and coupled via the support structure (36) to the active assembly (32, 34) so that vibration of the active assembly (32, 34) drives the passive vibrator (38). The active assembly (32, 34) and the passive vibrator (38) have the same resonant frequency.

Techniques are disclosed for systems and methods to provide accurate and reliable compact sonar systems for mobile structures. A sonar system includes multiple sensor channels, each comprising a sonar transmitter and a sonar receiver, and a logic device configured to provide control signals and receive sensor signals from the sensor channels. The logic device is configured to provide transmission signals to sonar transducer assemblies, where signal patterns of the transmission signals are differentiated based at least in part on frequency content. Acoustic returns are processed using the signal patterns to reduce inter-channel pickup between the sensor channels. Resulting sonar data and/or imagery may be displayed to a user and/or used to adjust a steering actuator, a propulsion system thrust, and/or other operational systems of the mobile structure.

Techniques are disclosed for systems and methods to provide transmission signal shaping for transmission signal-based sensor systems, such as radar and/or sonar sensor systems. A low noise signal shaping transmitter includes a digital to analog converter configured to convert a digital shaping control signal to an analog shaping control signal, a signal shaping circuit configured to convert the analog shaping control signal into a shaped voltage, and a power amplifier configured to provide a shaped transmission signal based on the shaped voltage and a digital transmission control signal. Each element of the transmitter may be formed from relatively slow switching analog and/or digital circuitry components. Resulting shaped transmission signals may be used to excite radar antennas, sonar transducers, sound cells, and/or other elements of sensor systems.

Apparatus for controlling algae and bio-organisms in bodies of liquids, such as water. The algae control system includes a first set of ultrasonic transducers and a second set of ultrasonic transducers where at least the second set of transducers emits ultrasonic waves 360 degrees around a vertical axis of a submergible sonic head that includes the sets of transducers. The first set of transducers are controlled to emit ultrasonic waves within a first range of frequencies with a first selected duty cycle and said second set of transducers are controlled to emit ultrasonic waves within a second range of frequencies with a second selected duty cycle. The first and second range of frequencies target different species of organisms. The second set of transducers include one or more groups of transducers that are spaced horizontally around the vertical axis of the sonic head. The multiple groups operate independently of each other.

Transducers and processes of forming the transducers are described. The transducers are produced as a monolithic body of a ceramic material and electrodes embedded in and encased by the ceramic material, with the ceramic material and the electrodes being co-fired to produce the monolithic body. By embedding the electrodes in the ceramic material, the ceramic material protects the electrodes and isolates the electrodes from the environment, eliminating or reducing the need for separate sealing or potting material to isolate the electrodes from the surrounding environment. In addition, unique transducer designs can be produced, and the electrodes can have configurations and can be located in the transducer in locations that are not possible with traditional transducer production techniques.

A multi-resonance flextensional low frequency acoustic projector of the present disclosure includes a piezoelectric actuator; a plurality of staves attached to an outer surface of the piezoelectric actuator to convert longitudinal vibration generated by the piezoelectric actuator into lateral vibration perpendicular to the outer surface of the piezoelectric actuator; and an acoustic window surrounding an exterior of the staves and water-tightening the inside of the projector. The plurality of staves is configured in shapes different from each other to generate two or more types of resonance vibration modes, so there is an effect of allowing low frequency acoustic transmission in a wide frequency band.

Apparatus for controlling bio-organisms in bodies of water. The algae control system includes a power unit and a transducer unit that radiates in multiple directions. The transducer unit includes a variable power driver and a transducer subassembly. The power from the driver varies to maintain a maximum, constant transducer sonic output over its bandwidth. The transducer assembly includes at least one transducer that includes a pair of blocks with at least one piezoelectric element therebetween. One embodiment has a single, disc-shaped element adhesively secured between said blocks. The transducer is excited by applying power to the pair of blocks. Another embodiment has at least one ring-shaped elements compressed between the two blocks by way of a fastener. The transducer is excited by applying power, in one embodiment, between the blocks and a conductor between a pair of ring-shaped elements, or in another embodiment, between the pair of blocks.

An acoustic transducer (30) deployable in a sonobuoy application. The acoustic transducer (30) having a support structure (36) connecting a base plate (32) of an active assembly, comprising a base plate (32) and a piezoelectric body (34) supported by the base plate (32) to a passive vibrator (38) supported by the support structure (36). Such that bending vibration of the active assembly (32, 34) is mechanically coupled via the support structure (36) to drive bending vibration of the passive vibrator (38). Multiple acoustic transducers of this type can be used to form a transducer array for a sonobuoy.