The present invention relates to an electromagnetic acoustic transducer excitation system comprising a tone burst generator, the tone burst generator comprising: an oscillator device configured to produce a radio frequency signal; an analog switch configured to produce an output based on the radio frequency signal produced by the oscillator device and a control signal; a pre-amplifier configured to amplify the output of the analog switch and produce a tone burst output signal; and a control module configured to produce the control signal for providing to the analog switch.

An ultrasonic device includes a substrate, first ultrasonic elements having a resonance characteristic of a first frequency, and second ultrasonic elements having a resonance characteristic of a second frequency lower than the first frequency. The first ultrasonic elements are arranged along a first direction to make a first to an n-th high-frequency ultrasonic element lines. The second ultrasonic elements are arranged along the first direction to make a first to an n-th low-frequency ultrasonic element lines. The first to the n-th high-frequency ultrasonic element lines and the first to the n-th low-frequency ultrasonic element lines are arranged along a second direction. The first and second ultrasonic elements have an opening, a vibrating membrane, and a piezo element part. A length in the second direction of the opening of the first ultrasonic element is shorter than a length in the second direction of the opening of the second ultrasonic element.

A tactile sense presentation device includes a vibration unit including a piezoelectric element and having a resonance point in a tactile sense frequency band; and a self-oscillation circuit electrically coupled to the vibration unit, in which the piezoelectric element self-oscillates in a frequency band based on the resonance point by a drive voltage input from the self-oscillation circuit according to contact with the vibration unit.

Road vehicle comprising at least one electric motor; an acoustic system, which comprises at least one reproduction device, which generates a sound that can be associated with the electric motor; wherein the electric motor is mechanically connected to the reproduction device so as to be able to excite a resonant frequency thereof; and a control unit configured to control the electric motor so as to inject at least one sonority current or voltage, as an input, to the electric motor itself; wherein said at least one sonority current or voltage excites a frequency resulting in a vibration of said at least one reproduction device, which emits, due to the vibration, in the form of acoustic waves, a sound as a function of the injected sonority current or voltage.

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.

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.

Disclosed herein is an ultrasonic barrier chamber for fluid systems, for example, which facilitates making fluid lines airless using ultrasonic signals. In some examples, the fluid lines may include an extracorporeal blood circuit, for instance, for use in a dialysis process. In one example, a device for monitoring an extracorporeal circuit in which a blood pump is disposed to convey blood may include one or more ultrasonic transducers positioned in a predetermined vicinity of a vent of a drip chamber of the extracorporeal circuit, and a controller coupled to the one or more ultrasonic transducers, the controller configured to cause the one or more ultrasonic transducers to emit ultrasonic signals that displace particles in contents of the drip chamber away from the vent. Other embodiments are described.

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.

A bat deterrent system to deter bats from approaching wind turbines may include a first deterrent box having a first and second transducer bank. The first transducer bank may include a first set of transducers located on a first plane and a second set of transducers located on a second plane. The second plane may be different from the first plane. The bat deterrent system may also include a second deterrent box having a third and fourth transducer bank. The third transducer bank may include a third set of transducers located on a third plane and a fourth set of transducers located on a fourth plane. The fourth plane may be different from the third plane. At least one transducer may simultaneously emit a different ultrasonic output waveform than the ultrasonic output waveform emitted from another transducer.

In a deburring device configured to remove burrs of the molded product through radiation of ultrasonic waves, a height of the storage tank is set to 1.25 mm when a wavelength of an ultrasonic wave is set to mm. A frequency range of ultrasonic wave radiating means arranged on a bottom side of the washing water storage tank is set to from 18 KHz to 28 KHz, and power density is set to 2 W/cm.sup.2 or higher. Further, there is arranged oscillating means configured to allow the molded product immersed in the washing water to vertically move with a stroke of at least 1/2 mm in a vertical direction. Further, an amount of dissolved oxygen in the washing water is set to 1 mg/litter or less, and a water temperature of the deburring washing water is set to from 4 C. to 8 C.