A method for inspecting a crystal unit, the method includes: generating a sub-vibration in a crystal blank of the crystal unit by applying an input signal to a plurality of electrodes formed on the crystal blank; obtaining frequency characteristics of impedance between the plurality of electrodes from an output signal of the plurality of electrodes; and comparing the frequency characteristics obtained with reference frequency characteristics indicating quality of the crystal unit.

An acoustic module is coupled to an acoustic passage. The acoustic module includes an acoustic transducer coupled to a diaphragm. A controller or other circuitry measures an impedance of the acoustic transducer. Based on the impedance, the controller determines whether the impedance indicates that the acoustic passage is blocked. The controller may determine that the acoustic passage is blocked by liquid that is present in the acoustic passage. When the controller determines based on the impedance that liquid is present in the acoustic passage, the controller may drive out, purge, and/or otherwise remove the liquid, such as by using the acoustic transducer to vibrate the diaphragm.

An acoustic module is coupled to an acoustic passage. The acoustic module includes an acoustic transducer coupled to a diaphragm. A controller or other circuitry measures an impedance of the acoustic transducer. Based on the impedance, the controller determines whether the impedance indicates that the acoustic passage is blocked. The controller may determine that the acoustic passage is blocked by liquid that is present in the acoustic passage. When the controller determines based on the impedance that liquid is present in the acoustic passage, the controller may drive out, purge, and/or otherwise remove the liquid, such as by using the acoustic transducer to vibrate the diaphragm.

Disclosed are a device and a method for testing impedance characteristic and expansion performance of a sound absorption material. The device includes a first cavity and a second cavity which are both sealed. The first cavity is communicated with the second cavity through a slit channel. The second cavity is used for placing a sound absorption material therein. The device further includes a sound excitation source whose sounding face is located in the first cavity and used to provide a testing sound pressure. The device further includes two sound pickup sensors whose sound pickup surfaces are respectively arranged in the first cavity and the second cavity and respectively used to detect sound pressure in the first cavity and the second cavity. The device further includes a material for enclosing the first cavity and the second cavity is a hard sound insulation material.

Disclosed are a device and a method for testing impedance characteristic and expansion performance of a sound absorption material. The device includes a first cavity and a second cavity which are both sealed. The first cavity is communicated with the second cavity through a slit channel. The second cavity is used for placing a sound absorption material therein. The device further includes a sound excitation source whose sounding face is located in the first cavity and used to provide a testing sound pressure. The device further includes two sound pickup sensors whose sound pickup surfaces are respectively arranged in the first cavity and the second cavity and respectively used to detect sound pressure in the first cavity and the second cavity. The device further includes a material for enclosing the first cavity and the second cavity is a hard sound insulation material.

Some surgical instruments become partially or fully disabled at a device firmware level after being used in a surgical procedure in order to prevent overuse or abuse of the surgical instrument that could create patient safety concerns. A reconditioning device may be used by the end user of such a surgical instrument to perform diagnostics and reconditioning of the surgical instrument so that the surgical instrument may be placed back into service without the direct intervention of the manufacturer. The reconditioning device provides power to the surgical instrument, analyzes device usage history, activates and tests the surgical instrument cutting and gripping functions, and measures electrical characteristics and mechanical characteristics of the surgical instrument. Gathered data is used to determine if the surgical instrument may be safely reconditioned for further use. If reconditioning is possible, the device will be reconfigured for safe use, reactivated, and then sterilized for subsequent re-use.

Systems and methods for detecting faults are provided. A method for determining a fault condition for a component of a drivetrain in a wind turbine can include receiving an acoustic signal from an acoustic signal measuring device. The method can further include receiving a vibration signal from a vibration signal measuring device. The method can further include analyzing the acoustic signal to determine an analyzed acoustic signal. The method can further include analyzing the vibration signal to determine an analyzed vibration signal. The method can further include determining a fault condition for the component based at least in part on the analyzed acoustic signal and analyzed vibration signal. The fault condition can further be determined based at least in part on an analyzed electrical signal.

A method comprising: receiving, by an electronic device, a first signal having a first frequency; identifying, by the electronic device, at least one of a strength of the first signal or a signal-to-noise ratio of the first signal; outputting, by the electronic device, a second signal having a second frequency that is different from the first frequency, the second signal being output based on at least one of the strength of the first signal or the signal-to-noise ratio of the first signal; receiving the second signal by the electronic device; and detecting whether the electronic device is at least partially immersed in a liquid based on the received second signal.

A method comprising: receiving, by an electronic device, a first signal having a first frequency; identifying, by the electronic device, at least one of a strength of the first signal or a signal-to-noise ratio of the first signal; outputting, by the electronic device, a second signal having a second frequency that is different from the first frequency, the second signal being output based on at least one of the strength of the first signal or the signal-to-noise ratio of the first signal; receiving the second signal by the electronic device; and detecting whether the electronic device is at least partially immersed in a liquid based on the received second signal.

The invention relates to a system for measuring vibration on a machine, with a carrier (14) for placing onto a measuring point (12) of the machine, a sensor (16) arranged on the carrier for detecting vibrations, an arrangement (16, 22, 28, 30) for detecting the electromechanical impedance of the sensor and also a monitoring device (22, 24, 26) for monitoring the current coupling of the carrier at the measuring point by means of evaluating the detected electromechanical impedance. The current coupling is in this case determined from the difference between the currently detected electromechanical impedance and the electromechanical impedance detected for a prescribed optimum coupling of the carrier to the measuring point.