An amplifier circuit to be used in a sonar is described. The amplifier circuit includes a transducer and a matching circuit. The transducer has an impedance characteristic having a resonance frequency and an anti-resonance frequency higher than the resonance frequency. The matching circuit is connected to the transducer. The impedance characteristic of the transducer connected to the matching circuit has a first resonance frequency and a second resonance frequency higher than the first resonance frequency.

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.

Systems and methods for the ultrasonic disruption of biofilm and algae growth on underwater structures utilize an ultrasonic actuator that produces a natural frequency in the ultrasonic range. In some embodiments, the ultrasonic actuator includes one or more piezoelectric transducers.

The method and system uses ultrasound (US) transducers in contact with an inboard surface underwater portions of marine vessels or structures. By first digitally generating disruptive, multi-frequency, interfering US waveform signals (complex waveforms, typically replicating a Bessel function) and then converting the signals into analog, the transducers generate disruptive, multi-frequency, interfering US waveforms through the underwater portions of the marine vessels and structures which waveforms disrupt unwanted marine growth on the water-side of the vessel or structure. The digital signals, and also the analog signals, are complex waveform signals, typically produced with a Bessel function. The US transducers are either circular membrane transducers or surface transducers. A computer processor coupled to a memory, generates the complex waveform signals fed to the US transducers.

This invention claims a patent on the process of propagating soundwaves through bodies of water, such as oceans, to produce and direct winds, for the purpose of managing aerial weather systems. Propagating soundwaves within water can generate and direct wind for many purposes. One purpose is to effectively weaken storms, by directing wind-shear against a storm's momentum, and stripping it of precipitation. Another purpose is to guide atmospheric rivers, and manually re-direct clouds in the precipitation cycle. This inventive process grants methods to mitigate dangerous weather patterns, such as droughts and hurricanes. The invention introduces a new subject matter that distinguishes it from other inventions relevant to underwater acoustics: manual processes to moderate weather.

A sound source for acoustic communication, navigation, and networking of an underwater glider may include a cylindrical body, a rigid front section disposed anteriorly to the cylindrical body, a plurality of metal rods, a resonant pipe surrounding the rods, and a rod-mounted piezo-ceramic transducer disposed between the body and the front section. Each rod may be attached at a first end to an anterior portion of the body and at a second end to a posterior portion of the front section. The pipe may be disposed between the body and the front section. The transducer may be disposed within the pipe. A posterior end of the pipe may be separated from the anterior portion of the body by a first orifice, and an anterior end of the pipe may be separated from the posterior portion of the front section by a second orifice.

The method and system uses ultrasound (US) transducers in contact with an inboard surface underwater portions of marine vessels or structures. By first digitally generating disruptive, multi-frequency, interfering US waveform signals (complex waveforms, typically replicating a Bessel function) and then converting the signals into analog, the transducers generate disruptive, multi-frequency, interfering US waveforms through the underwater portions of the marine vessels and structures which waveforms disrupt unwanted marine growth on the water-side of the vessel or structure. The digital signals, and also the analog signals, are complex waveform signals, typically produced with a Bessel function. The US transducers are either circular membrane transducers or surface transducers. A computer processor coupled to a memory, generates the complex waveform signals fed to the US transducers.

An acoustic antenna intended to equip a sonar, the antenna being centred around a first longitudinal axis and includes at least a first assembly of at least two transducers and a second assembly of at least two transducers stacked along the longitudinal axis, each transducer having at least a radial mode having a resonance frequency, referred to as the radial frequency, and a cavity mode having a resonance frequency, referred to as the cavity frequency, wherein the transducers of the first assembly are configured to transmit sound waves in a first continuous frequency band extending at least between the cavity and radial frequencies of the transducers of the first assembly and the transducers of the second assembly are configured to transmit sound waves in a second continuous frequency band extending at least between the cavity and radial frequencies of the transducers of the second assembly, in that the cavity frequency of a transducer of the second assembly is equal to the radial frequency of a transducer of the first assembly plus or minus (fr1−fc1)/10, fr1 being the radial frequency of the transducer of the first assembly and fc1 being the cavity frequency of the transducers of the first assembly and wherein the transducers of the second assembly are positioned between the transducers of the first assembly and in that no transducer of the first assembly is positioned between the transducers of the second assembly.

The invention relates to hydroacoustic domain, notably to methods and devices of active location. The method of controlling intercarrier frequency wave efficiency with parametric radiating antenna is based on placing electroacoustic transducer with piezoelement with given resonance frequency (f.sub.1+f.sub.2)/2=f.sub.0 and pass band corresponding to intercarrier frequency wave diapason in locating area, feeding electric signals from radiating tract output to electroacoustic transducer piezoelement, forming in locating area spatial area of collinear distribution and non-linear interaction of intense ultrasound pimp waves, generation of intercarrier frequency wave with cyclic frequency Ω=2π|f.sub.1−f.sub.2|. New features are the following: multicomponent excitation signal if formed due to generating in radiating tract N oscillations with similar amplitude and with similar initial phase at the period of time t=0), with frequencies ω.sub.v, sequentially differing from each other by Ω=2πF_ and situated in pass band of piezoelement and coming from radiating tract output to piezoelement with resonance cyclic frequency ω.sub.0=2πf.sub.0 electric multicomponent signal of escitation, presented as sum of N oscillations and regulation of generation efficiency and adjusting of field parameters (N−1) of intercarrier frequency component wave with cyclical frequencies Ω, 2Ω, . . . , (N−1)Ω formed by parametric radiating antenna, implemented by switching off of antiphase switching on of given constituents set. The method is implemented due to the device that includes reference generator, delayed pulse-shaping circuit, (N−1) coincidence circuit, N frequency dividers, analog switch, adder, amplitude modulator, impulse generator, power amplifier, electroacoustic transducer, controlling and adjustment unit.

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.