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.

A method for carrying out acoustic Thevenin calibration of probes or hearing aids comprises presenting a plurality of different acoustic loads, one acoustic load at a time, to the output of the probe or hearing aid, the source characteristic of which is to be determined. Each of the acoustic loads is characterized by a known acoustic input impedance and an additional frequency dependent complex correction factor ?Z(f). By applying the method according to the present disclosure the relationship between the sound pressure and the volume velocity at the input of the acoustic load generated by the probe can be determined for a plurality of frequencies, thereby obtaining the substantially correct source characteristic of the probe or a hearing aid. Specifically the acoustic loads are the input impedance of respective waveguides or other suitable cavities, and the known acoustic input impedances are determined analytically. The correction factors are adjusted individually for each waveguide or cavity, for instance in an iterative process.

A method for carrying out acoustic Thevenin calibration of probes or hearing aids comprises presenting a plurality of different acoustic loads, one acoustic load at a time, to the output of the probe or hearing aid, the source characteristic of which is to be determined. Each of the acoustic loads is characterized by a known acoustic input impedance and an additional frequency dependent complex correction factor ?Z(f). By applying the method according to the present disclosure the relationship between the sound pressure and the volume velocity at the input of the acoustic load generated by the probe can be determined for a plurality of frequencies, thereby obtaining the substantially correct source characteristic of the probe or a hearing aid. Specifically the acoustic loads are the input impedance of respective waveguides or other suitable cavities, and the known acoustic input impedances are determined analytically. The correction factors are adjusted individually for each waveguide or cavity, for instance in an iterative process.

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.

An earth-boring tool includes a cutting element comprising a hard material and at least one of a signal generator configured to provide an electromagnetic or acoustic signal to an interface between a surface of the hard material and a surface of a subterranean formation, and a sensor configured to receive an electromagnetic or acoustic signal from the interface. A method of forming a wellbore includes rotating the earth-boring tool within a wellbore and cutting formation material with a cutting element, transmitting a signal through the cutting element to an interface between the cutting element and the formation material, and measuring a response received at a sensor. A cutting element includes a transmitter oriented and configured to dispense a signal to an interface between the cutting surface and a surface of a formation and a sensor oriented and configured to measure a signal from the interface.

An earth-boring tool includes a cutting element comprising a hard material and at least one of a signal generator configured to provide an electromagnetic or acoustic signal to an interface between a surface of the hard material and a surface of a subterranean formation, and a sensor configured to receive an electromagnetic or acoustic signal from the interface. A method of forming a wellbore includes rotating the earth-boring tool within a wellbore and cutting formation material with a cutting element, transmitting a signal through the cutting element to an interface between the cutting element and the formation material, and measuring a response received at a sensor. A cutting element includes a transmitter oriented and configured to dispense a signal to an interface between the cutting surface and a surface of a formation and a sensor oriented and configured to measure a signal from the interface.

A sound isolation testing system and a sound isolation testing method are provided. The sound isolation testing system is adapted to test a product having a sound hole, and includes a detection device and a gas pressure detector. The detection device includes a gas cover, and the sound hole is sealed by the gas cover. The gas pressure detector is electrically connected to the detection device. The gas pressure detector determines a gas pressure change rate in the sound hole, and calculates the sound isolation value of the product according to the gas pressure change rate.

A sound isolation testing system and a sound isolation testing method are provided. The sound isolation testing system is adapted to test a product having a sound hole, and includes a detection device and a gas pressure detector. The detection device includes a gas cover, and the sound hole is sealed by the gas cover. The gas pressure detector is electrically connected to the detection device. The gas pressure detector determines a gas pressure change rate in the sound hole, and calculates the sound isolation value of the product according to the gas pressure change rate.

A system and/or method for RF interrogation to read surface properties such as ultrasonic impedance and temperature in the field of measuring signals at a distance. The system includes a substrate with one or more piezoelectric transducers, at least one antenna connected to the substrate or formed onto the substrate, and one or more antenna terminals extending from the antenna and connected to terminals of at least one piezoelectric transducer. The antenna receives a radio frequency pulse and actuates at least one piezoelectric transducer. The piezoelectric transducer generates an ultrasonic pulse that reflects off a back side of the substrate. The reflected ultrasonic pulse is received at the piezoelectric transducer and drives the antenna that initially received the radio frequency pulse.