A method for controlling at least two mechanical oscillators, more particularly in a motor vehicle, where each oscillator oscillates at a frequency during operation and where the frequency can be controlled by the power applied to the oscillators, includes arranging a single sound transducer at a distance from the oscillators and capturing an electrical signal, where the electrical signal is subjected to a Fourier transform and thus a Fourier spectrum is determined. The frequency of each oscillator is determined from extreme values of the Fourier spectrum.

A method for controlling at least two mechanical oscillators, more particularly in a motor vehicle, where each oscillator oscillates at a frequency during operation and where the frequency can be controlled by the power applied to the oscillators, includes arranging a single sound transducer at a distance from the oscillators and capturing an electrical signal, where the electrical signal is subjected to a Fourier transform and thus a Fourier spectrum is determined. The frequency of each oscillator is determined from extreme values of the Fourier spectrum.

A system comprising a first electroacoustic transducer connected to an interrogation unit and at least one second electroacoustic transducer connected to a resonator, wherein the first electroacoustic transducer and the second electroacoustic transducer form an acoustic channel and the second electroacoustic transducer forms with the resonator a passive cooperative target which, upon receiving an interrogation signal from the interrogation unit, transmits a response signal via the acoustic channel, and the interrogation signal has a higher energy than the response signal.

A system comprising a first electroacoustic transducer connected to an interrogation unit and at least one second electroacoustic transducer connected to a resonator, wherein the first electroacoustic transducer and the second electroacoustic transducer form an acoustic channel and the second electroacoustic transducer forms with the resonator a passive cooperative target which, upon receiving an interrogation signal from the interrogation unit, transmits a response signal via the acoustic channel, and the interrogation signal has a higher energy than the response signal.

An apparatus includes a mass detection circuit coupled to a surface covered with a plurality of electrodes. The mass detection circuit is configured to detect a mass of a first droplet present on the surface. The apparatus further includes a transducer circuit coupled to a transducer, which is coupled to the surface and form a lens unit. The transducer circuit configured to excite a first vibration of the surface at a resonant frequency to form a high displacement region on the surface. The apparatus also includes a voltage excitation circuit coupled to the plurality of electrodes. In response to the detection of the mass of the first droplet, the voltage excitation circuit is configured to apply a sequence of differential voltages on one or more consecutive electrodes which moves the first droplet to the high displacement region.

An apparatus includes a mass detection circuit coupled to a surface covered with a plurality of electrodes. The mass detection circuit is configured to detect a mass of a first droplet present on the surface. The apparatus further includes a transducer circuit coupled to a transducer, which is coupled to the surface and form a lens unit. The transducer circuit configured to excite a first vibration of the surface at a resonant frequency to form a high displacement region on the surface. The apparatus also includes a voltage excitation circuit coupled to the plurality of electrodes. In response to the detection of the mass of the first droplet, the voltage excitation circuit is configured to apply a sequence of differential voltages on one or more consecutive electrodes which moves the first droplet to the high displacement region.

An electro-acoustical transducer such as a Piezoelectric Micromachined Ultrasonic Transducers is coupled with an adjustable load circuit having a set of adjustable load parameters including resistance and inductance parameters. Starting from at least one resonance frequency or at least one ring-down parameter of the electro-acoustical transducer a set of model parameters is calculated for a Butterworth-Van Dyke (BVD) model of the electro-acoustical transducer. The BVD model includes an equivalent circuit network having a constant capacitance coupled to a RLC branch and the adjustable load circuit is coupled with the electro-acoustical transducer at an input port of the equivalent circuit network of the model of the electro-acoustical transducer. The adjustable load parameters are adjusted as a function of the set of model parameters calculated for the BVD model of the electro-acoustic transducer to increase the bandwidth or the sensitivity of the electro-acoustic transducer.

An electro-acoustical transducer such as a Piezoelectric Micromachined Ultrasonic Transducers is coupled with an adjustable load circuit having a set of adjustable load parameters including resistance and inductance parameters. Starting from at least one resonance frequency or at least one ring-down parameter of the electro-acoustical transducer a set of model parameters is calculated for a Butterworth-Van Dyke (BVD) model of the electro-acoustical transducer. The BVD model includes an equivalent circuit network having a constant capacitance coupled to a RLC branch and the adjustable load circuit is coupled with the electro-acoustical transducer at an input port of the equivalent circuit network of the model of the electro-acoustical transducer. The adjustable load parameters are adjusted as a function of the set of model parameters calculated for the BVD model of the electro-acoustic transducer to increase the bandwidth or the sensitivity of the electro-acoustic transducer.

A measurement method includes: generating second measurement data by performing filter processing on first measurement data; calculating a first deflection amount based on an approximate equation of deflection of a structure; calculating a second deflection amount by performing filter processing on the first deflection amount; calculating a third deflection amount based on the second deflection amount and a first-order coefficient and a zero-order coefficient which are calculated based on the second measurement data and the second deflection amount; calculating an offset based on the zero-order coefficient, the second deflection amount, and the third deflection amount; calculating a static response by adding the offset and a product of the first-order coefficient and the first deflection amount; calculating a first dynamic response by subtracting the static response from the first measurement data; calculating a second dynamic response by attenuating an unnecessary signal from the first dynamic response; and calculating an attenuation rate of the second dynamic response based on an envelope amplitude of the second dynamic response.

A measurement method includes: generating second measurement data by performing filter processing on observation data-based first measurement data; calculating a first deflection amount of a structure based on an approximate equation of deflection of the structure, observation information, and environment information; calculating a second deflection amount by performing filter processing on the first deflection amount; calculating a third deflection amount based on the second deflection amount and a first-order coefficient and a zero-order coefficient which are calculated based on the second measurement data and the second deflection amount, and the second deflection amount; calculating an offset based on the zero-order coefficient, the second deflection amount, and the third deflection amount; calculating a first static response by adding the offset and a product of the first-order coefficient and the first deflection amount; and calculating a first dynamic response by subtracting the first static response from the first measurement data.