A system includes sensor-actuator units fixed onto a plate to be actuated according to at least one predetermined vibratory mode, each sensor-actuator unit having an electromechanical actuator and a deformation or vibratory speed sensor, wherein the electromechanical actuator and the sensor are colocated on the surface, that is to say that the measurement by the sensor is performed in immediate proximity to the electromechanical actuator, this proximity being such that the actuator and the sensor can respectively actuate and measure the same predetermined vibratory mode.

A driving device generates a driving signal and outputs the driving signal to a piezoelectric element, the driving signal having a waveform obtained by using, as a first modulated wave, a first low-frequency wave having a frequency of 1 Hz or more and less than 100 Hz, using, as a second modulated wave, a waveform obtained by modulating an amplitude of a second low-frequency wave having a frequency of 100 Hz or more and 300 Hz or less with the first modulated wave, and modulating a high-frequency wave having a frequency of 20 kHz or more and 100 kHz or less with the second modulated wave.

Electroacoustic device (5) for generating at least one acoustic wave (Fv,Vx), the device comprising a piezoelectric substrate (10) and first (15) and second (20) groups of electrodes (60,65,70,75) arranged on the substrate, each electrode of the first and second groups comprising a track (80.sub.a-f,85.sub.a-f,90.sub.a-d,95.sub.a-d), the tracks (90.sub.a-d,95.sub.a-d) of the electrodes of the first group spiralling around a same spiral axis (Z) along a first winding direction (W.sub.1), and the tracks (80.sub.a-f,85.sub.a-f) of the electrodes of the second group spiralling around said spiral axis along a second winding direction (W.sub.2) opposite to the first winding direction.

An ultrasonic surgical tool system with a tip capable of simultaneously vibrating in plural modes. The system includes a console capable of supplying a drive signal to the tip that includes plural components. Each component has a frequency characteristic that is based in part on the equivalent of current through the mechanical components of the tip. The frequency components are different from each other. Based on the application of drive signal the tip undergoes non-linear vibrations.

A multi-frequency ultrasound therapy apparatus is configured to operate at its center frequency and at the higher harmonic of its center frequency. The center frequency can be for the entire apparatus or for each ultrasound source element. At least one source element can generate ultrasound energy at its center frequency while, simultaneously, at least another source element can generate ultrasound energy at the higher harmonic of its center frequency. In addition, the same source element can generate ultrasound energy at its center frequency and the higher harmonic of its center frequency, respectively, but at different times. A data storage unit that stores encrypted and encoded data is disposed on the apparatus. The encoded data includes a unique identification code of the apparatus, the condition of use of the apparatus, the center frequency of each source element, the ultrasound efficiency of each source element, and/or other parameters relating to the apparatus.

A vibration apparatus may include a vibration device and an adhesive member at a surface of the vibration device. A modulus of the vibration device may be equal to a modulus of the adhesive member or may be greater than the modulus of the adhesive member.

A wearable element is disclosed. In an embodiment a wearable element includes at least one piezoelectric element configured to vibrate so that a haptic impression of an acoustic signal is generated, wherein the wearable element is wearable on a body.

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.

A method of providing a haptic signal is described therein, the method comprising the steps of providing a first source signal, filtering a mid-range band of the first source signal for restricting a bandwidth of the first source signal to the mid-range band, integrating the filtered mid-range band of the first source signal to identify an amplitude of the filtered first source signal, providing a voltage control amplifier with a proportional calibrated voltage on a basis of the integration of the filtered first source signal for adjusting an amplitude of the filtered source signal, isolating a trans-conductance voltage control amplifier high impedance output from a second source signal with a buffer, filtering the filtered source signal with a low pass filter to identify original sub-frequencies of an audio program and combining the identified original sub frequencies of the audio program with transposed midrange frequencies in a haptic signal.

Provided is a driving apparatus that sets a signal wave in a low-frequency region having a frequency of 10 Hz or more and 250 Hz or less as a modulating wave and outputs to a piezoelectric actuator a driving signal having a waveform obtained by modulating an amplitude of a sine wave in a high-frequency region having a frequency of 20 kHz or more and 40 kHz or less with the modulating wave.