An ultrasonic transducer is described. The ultrasonic transducer comprises a membrane and a substrate disposed opposite the membrane such that a cavity is formed therebetween. The substrate comprises an electrode region and pedestals protruding from a surface of the substrate and having a height greater than a height of the electrode region, the pedestals being electrically isolated from the electrode region.

An acoustic sensor includes a piezoelectric plate including a conductor plate with first and second surfaces, and a piezoelectric element on the second surface, a cover facing the first surface of the conductor plate, a support substrate facing the second surface of the conductor plate and the piezoelectric element, a first connector including a conductor between the piezoelectric element and the support substrate and electrically connecting the piezoelectric element and the support substrate, a first insulating structure including an insulator between the second surface of the conductor plate and the support substrate at an outer edge of the second surface of the conductor plate, and a second connector including a conductor on an outer edge of the first surface of the conductor plate and electrically connecting the conductor plate and the cover.

The infrasound generating device based on a displacement-feedback type vibration exciter comprises a displacement-feedback type vibration exciter system, an infrasound generating chamber (3) and a laser vibrometer (1); the displacement feedback mechanism is adopted in the vibration exciter (2). The piston (31) is driven by the vibration exciter to move in a sinusoidal manner in the cavity (35) of the airtight infrasound generating chamber (3) and the standard infrasonic pressure signal with low harmonic distortion can be achieved. The displacement of the moving part (22) of the vibration exciter (2) can be measured by the laser vibrometer (1) through the measurement beam (15) injecting into the vibration exciter (2) through the optical channel running through the vibration exciter and the standard infrasonic pressure can also be obtained. The value of the standard sound pressure produced by the infrasound generating chamber is calculated. Such value is used as the calibration reference for the infrasound sensors (4) to be calibrated in order to achieve the primary calibration of the infrasound sensors. The standard infrasonic sensor can be installed inside the infrasound generating chamber (3) and the output of the standard infrasonic sensor can be used as the reference for the infrasonic sensor (4) to be calibrated in order to achieve the secondary calibration of the infrasound sensors. This invention has the advantages of technical maturity, high feasibility, easy to realize, high calibration accuracy and so on.

An ultrasonic vibration sub-element including a substrate, a ground layer, a first insulation layer, a second insulation layer, a first electrode layer, a third insulation layer, and a second electrode layer is provided. The first electrode layer is configured to receive a direct current voltage. The second electrode layer is configured to receive an alternating current signal. Before the ultrasonic vibration sub-element is driven, there is a cavity between the first insulation layer and the second insulation layer. When the ultrasonic vibration sub-element is driven, the first electrode layer receives the direct current voltage and is configured to at least drive the second insulation layer to shrink toward the cavity. The second electrode layer receives the alternating current signal and is configured to at least drive the third insulation layer to vibrate. An ultrasound probe is also provided.

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.

One or more systems, devices, computer-implemented methods and/or computer program products of use provided herein relate to ultrasound coexistence in an FMS. A system can comprise a memory that can store computer-executable components. The system can further comprise a processor that can execute the computer-executable components stored in the memory, wherein the computer-executable components can comprise a frequency generation component that can use a variable frequency generator circuitry to generate electronic signals at one or more different frequencies in at least one fetal sensor device (FSD) of a fetal monitoring system (FMS), wherein the electronic signals can cause a transducer of the at least one FSD to generate ultrasound signals at the one or more different frequencies.

Control consoles and methods for supplying a drive signal to a surgical tool are provided. The control console comprises a transformer with primary and secondary windings. The primary winding receives an input signal from a power source and induces the drive signal in the secondary winding to supply the drive signal to the surgical tool. A first current source comprising a leakage control winding is coupled to a path of the drive signal. The primary winding induces a first cancellation current in the leakage control winding to inject into the path of the drive signal to cancel leakage current. A sensor coupled to the path of the drive signal outputs a sensed signal to provide feedback related to leakage current. The sensor may connect to a second leakage current cancellation source and/or a fault detection stage. The power source may be variable and may also energize the second current source.

A system and method for detecting an anomaly in a structure using an adaptive filter to compensate for variations in piezoelectric transducer performance due to environmental factors such as temperature. A first voltage signal having a first amplitude is sent to a reference piezoelectric actuator. Thereafter, a first reference voltage signal is received from a reference piezoelectric receiver which is acoustically coupled to detect the guided wave generated by the reference piezoelectric actuator. A second amplitude is determined using an optimization algorithm of an adaptive filter to compensate for nonlinear behavior of the reference piezoelectric actuator and receiver based on the first reference voltage signal. Then the adaptive filter sends a second voltage signal having the second amplitude to the reference and test piezoelectric actuators. Reference and test voltage signals are received from the reference and test piezoelectric receivers in response to the second voltage signal. A difference voltage signal representing differences between the reference and test voltage signals received is then recorded.

The invention refers to a driving circuit (2) for a piezoelectric ultrasonic transducer (4) in an ultrasonic transducer system (1), comprising: a transformer (21) having at least one primary-side winding (22, 22, 22); a switching unit having a semiconductor switch (24, 24) connected to the at least one primary-side winding (22, 22, 22) via a switched connection (A, A); and, a control unit (5) which is configured to alternately apply an operating voltage (U.sub.B) to the at least one primary-side winding (22, 22, 22) or to disconnect it therefrom, a protection circuit (25) which is electrically coupled to the switched connection (A, A) and which has a Zener diode (ZD1) which limits a switch-off voltage at the switched connection (A, A) in terms of magnitude to a limiting voltage (U.sub.G) which corresponds to at least twice the operating voltage.

A frequency tracking method and system for ultrasonic transducer and an ultrasonic device are disclosed. The frequency tracking method for ultrasonic transducer includes the following steps: calculating the phase difference of voltage and current based on acquired voltage and current signals; determining whether the phase difference of the voltage and current is greater than a target phase difference; if not, reducing the operating frequency and calculating the adjusted operating frequency; if yes, calculating a phase difference change rate, determining whether to increase or decrease the operating frequency based on the phase difference change rate, and calculating the adjusted operating frequency. When performing ultrasonic transducer frequency tracking, the method uses the phase difference change rate to distinguish the working state of the ultrasonic transducer, thereby avoiding the problem that frequency locking fails because the minimum value of the phase difference of voltage and current corresponding to the working frequency range is greater than the phase-locking phase, and that the ultrasonic device is unable to work normally. At the same time, automatic frequency tracking is effectively realized, and the working efficiency and stability of the ultrasonic device are improved.