Abstract: A sensor system includes a first metamaterial track mechanically coupled to a rotational shaft configured to rotate about a rotational axis, wherein the first metamaterial track is arranged at least partially around the rotational axis, and wherein the first metamaterial track includes a first array of elementary structures; at least one transmitter configured to transmit a first continuous wave towards the first metamaterial track, wherein the first metamaterial track is configured to convert the first continuous wave into a first receive signal based on a rotational parameter of the rotational shaft; and at least one quadrature continuous-wave receiver configured to receive the first receive signal, acquire a first measurement of a first property of the first receive signal, and determine a measurement value for the rotational parameter of the rotational shaft based on the first measurement.

Abstract: A watch winding device includes a motor driving a winding operation, an acoustic measurer of the oscillator of a watch in the winding position, and a controller analysing the signals transmitted by the measurer and comparing them to desired values that can be parameterized to regulate the operation of the motor by starting this motor when the operating amplitude of the oscillator is less than a minimum value, and by stopping this motor when the working amplitude is higher than a maximum value, these acoustic measurers are fixed in a base behind an sensing opening of the acoustic sensor. The device includes an acoustic duct which places a receiving port, located inside a chamber for housing a watch, in communication with a transmitting port movable by the motor facing this sensing opening.

Abstract: An acceleration sensor capable of improving sensitivity is provided. In the acceleration sensor, although a solder fillet is formed in a lower end of a terminal electrode exposed from a covering portion, the covering portion suppresses the rise of the solder fillet. Due to this, the operation of the acceleration sensor is not easily limited by the solder fillet, and the acceleration sensor can generate electric charge which corresponds to a load more accurately. Therefore, the sensitivity of the acceleration sensor can be improved.

Abstract: Embodiments of the present invention provide for a transmission line stub that includes a via stub of a conductive via. The conductive via includes a via stub and a coupling element, wherein a first transmission line configured to transmit a signal is coupled to the conductive via at the intersection of the via stub and the coupling element. The coupling element is configured to transmit the signal from the first transmission line. A line stub electrically coupled to the via stub, wherein the length of the line stub is selected such that the transmission line stub having a length of the sum of the lengths of the via stub and the line stub is configured to suppress a preselected frequency.

Abstract: Methods and devices relating to measuring a landing position and mass of an analyte adsorbed to a nanomechanical resonator by resolving adsorbate-induced frequency shifts in at least two modes of a resonator resonance frequency, where during the resolving of the frequency shifts in the at least two modes analysis is so that the transformation (G) from the fractional-frequency shift pair to the analyte mass-position pair is one-to-one. Complex protein mixtures can be analyzed at high sensitivity and resolution.

Abstract: A method for configuring an electrical circuit comprising several functional blocks having characteristic quantities of the same type and the values whereof are mutually proportional, the functional blocks being built by means of at least one set of electrical elements of a similar type and means for connecting said electrical elements to one another and/or to the rest of the electrical circuit according to different connection configurations, comprising the steps consisting of: measuring a value of a parameter of the electrical circuit for each of a set of connection configurations tested, selection, from among the coupling configurations tested, of one configuration for which the value of the measured parameter corresponds to the case where the mismatch between the values of the characteristic quantities of at least one pair of functional blocks is the smallest, and positioning the connecting means according to the configuration selected.

Abstract: An electrical waveform generator for driving an electromechanical load includes a digital signal processor connected to a waveform generator component in turn connected to an amplifier section with a filter network, the latter being connected to sensing and conditioning circuit componentry that is in turn connected to analog-to-digital converter circuitry. A digital memory stores digitized voltage and current waveform information. The processor determines a phase difference between voltage and current waveforms, compares the determined phase difference to a phase difference command and generates a phase error or correction signal. The processor also generates an amplitude error signal for inducing the amplifier section to change its output amplitude to result in a predetermined amplitude error level for a respective one of the voltage and current waveforms.

Abstract: A frequency measuring device according to an embodiment of the invention includes a first resonator provided with a first adsorption film, a second resonator provided with a second adsorption film, a first oscillation circuit which is connected to the first resonator and is provided with a first frequency regulator that can regulate the frequency of a first oscillation signal and output the first oscillation signal, a second oscillation circuit which is connected to the second resonator and is provided with a second frequency regulator that can regulate the frequency of a second oscillation signal and output the second oscillation signal, a measuring circuit which can measure the frequencies of the first oscillation signal and the second oscillation signal, and a control circuit which can control the first frequency regulator and the second frequency regulator.

Abstract: A fully-functional radio receiver fabricated from a single nanotube is being disclosed. Simultaneously, a single nanotube can perform the functions of all major components of a radio: antenna, tunable band-pass filter, amplifier, and demodulator. A DC voltage source, as supplied by a battery, can power the radio. Using carrier waves in the commercially relevant 40-400 MHz range and both frequency and amplitude modulation techniques, successful music and voice reception has been demonstrated. Also disclosed are a radio transmitter and a mass sensor using a nanotube resonator device.

Abstract: In an ultrasound probe (2) and a method for manufacturing the ultrasound probe (2) of the invention, an organic piezoelectric element (21) has a sheet-like form, and is directly or indirectly laminated on a part or the entirety of a plurality of inorganic piezoelectric elements (22). Accordingly, the ultrasound probe (2) can be manufactured with a less number of steps. An ultrasound diagnostic apparatus of the invention includes the ultrasound probe (2). Accordingly, the cost of the ultrasound diagnostic apparatus can be reduced.

Abstract: Embodiments of the invention provide for three-terminal pressure sensors (“3-TPS”), a method of measuring a pressure with a 3-TPS, and a method of manufacturing a 3-TPS. In some embodiments, the 3-TPS includes a semiconducting layer with cavity and a 3-TPS element having at least one piezoresistive layer overlapping at least a portion of the cavity and oriented at an angle selected to provide a desired sensitivity for the 3-TPS. The method of measuring a pressure with a 3-TPS is performed with a 3-TPS that includes an input terminal, first and second output terminals, and a 3-TPS element, the 3-TPS element overlapping at least a portion of a cavity at a predetermined angle. The method comprises providing an input signal to the input terminal of the 3-TPS, determining a difference between two output signals from the respective output terminals of the 3-TPS, and correlating the determined difference to a pressure.

Abstract: A phase comparator (4) for detecting a phase difference between a first signal and a second signal, a first oscillating circuit (1) for supplying the phase comparator with a reference signal as the first signal, and a DDS (8) as a second oscillating circuit for outputting a signal according to an output of the above-mentioned phase comparator are provided. As for a filter-thickness measuring device using the PLL circuit as a frequency measurement circuit, a crystal oscillator (11) which is made of quartz etc. and connected to the first oscillating circuit is accommodated in a vacuum chamber (C). It is arranged that the frequency measurement circuit which constitutes the PLL circuit measures a film thickness of the film forming material based on a change of a natural frequency of a piezoelectric crystal, the change being caused by the film forming material deposited on the piezoelectric element in the vacuum chamber.

Abstract: A system and method for transmitting communication data of a fixed line phone include acquiring the communication data of the fixed line phone, writing the communication data into a radio frequency identification (RFID) tag. The system and method further include establishing a communication between the fixed line phone and a handheld device using the RFID tag and a RFID reader of the handheld device, and transmitting the communication data in the RFID tag to the RFID reader.

Abstract: A system, device, method, and apparatus provide the ability to wire a voltage sensitive device to a nanoelectromechanical system (NEMS) resonator. A voltage sensitive device is configured to detect one or more voltage signals and output one or more electrical potentials in real-time. An array of piezoelectric NEMS resonators (with each resonator tuned to a unique frequency) is used to receive the output electrical potentials and convert each output electrical potential to a corresponding resonance frequency varying signal. The output signal from each resonator varies in linear proportion to the resonator's corresponding frequency variation arising from the applied electrical potential. The frequency varying signals are multiplexed together into a single readout signal path that is monitored to determine variations in vibrational amplitude. A demodulation device deconvolves the multiplexed frequency varying signals to recover and uniquely identify the output electrical signal.

Abstract: An auditory prosthesis comprising an actuator for providing mechanical stimulation to a recipient. The auditory prosthesis comprises a measurement circuit for use in determining the resonance peak(s) of the actuator. In an embodiment, the measurement circuit measures the voltage drop across the actuator and/or current through the actuator during a frequency sweep of the operational frequencies of the actuator. These measured voltages and/or currents are then analyzed for discontinuities that are indicative of a resonance peak of the actuator. In another embodiment, rather than using a frequency sweep to measure voltages and/or currents across the actuator, the measurement circuit instead applies a voltage impulse to the actuator and then measure the voltage and/or current across the actuator for a period of time after application of the impulse. The measured voltages and/or currents are then analyzed to identify resonance peak(s) of the actuator.

Abstract: Described herein are techniques for determining a board parasitic capacitance of a crystal oscillator circuit. A crystal's frequency is measured under load condition off-circuit. After coupling the crystal to the oscillator circuit, external capacitors may be adjusted to produce frequencies approximating the off-circuit measurement with upper and lower margins. Calculation of the load capacitor values at the exact frequency measured off-circuit allows for derivation of the board parasitic capacitance by subtracting the calculated capacitor values from the original total load value used in the off-circuit measurement.

Abstract: A frequency measuring device according to an embodiment of the invention includes a first resonator provided with a first adsorption film, a second resonator provided with a second adsorption film, a first oscillation circuit which is connected to the first resonator and is provided with a first frequency regulator that can regulate the frequency of a first oscillation signal and output the first oscillation signal, a second oscillation circuit which is connected to the second resonator and is provided with a second frequency regulator that can regulate the frequency of a second oscillation signal and output the second oscillation signal, a measuring circuit which can measure the frequencies of the first oscillation signal and the second oscillation signal, and a control circuit which can control the first frequency regulator and the second frequency regulator.

Abstract: The resonant device comprises an electromechanical resonator of nanometric or micrometric size that comprises a mobile element and a fixed element. Detection means provide detection signals representative of movement of the mobile element with respect to the fixed element to a feedback loop that is connected to an excitation input of the resonator. The resonator is formed on the same substrate as the detection means and feedback loop. The feedback loop comprises at most first and second transistors connected in series between a reference voltage and the excitation terminal. A capacitive load is connected between the excitation terminal and reference voltage. The detection signals control the conductivity of the first transistor.

Abstract: A phase comparator (4) for detecting a phase difference between a first signal and a second signal, a first oscillating circuit (1) for supplying the phase comparator with a reference signal as the first signal, and a DDS (8) as a second oscillating circuit for outputting a signal according to an output of the above-mentioned phase comparator are provided. As for a filter-thickness measuring device using the PLL circuit as a frequency measurement circuit, a crystal oscillator (11) which is made of quartz etc. and connected to the first oscillating circuit is accommodated in a vacuum chamber (C). It is arranged that the frequency measurement circuit which constitutes the PLL circuit measures a film thickness of the film forming material based on a change of a natural frequency of a piezoelectric crystal, the change being caused by the film forming material deposited on the piezoelectric element in the vacuum chamber.

Abstract: A process for testing the quality, in particular the stiffness and the phase, of an elastic joint for connecting two other parts while filtering vibrations transmitted between these two other parts, said elastic joint being meant to work in axial, radial or torsional direction, disposing or not disposing of one or more hydro-elastic chambers and of two cylindrical concentric support elements, the inner support element being located to a large extend inside the volume defined by the outer support element, the two support elements being connected by a set of components made of rubber or elastomer or, if applicable, of plastic and metallic parts, wherein said support elements are themselves respectively attached to the two other parts which the elastic joint connects, wherein a technique of testing by impact is applied within the timing of the production line of the elastic joint, i.e.

Abstract: Embodiments of the invention provide for three-terminal pressure sensors (“3-TPS”), a method of measuring a pressure with a 3-TPS, and a method of manufacturing a 3-TPS. In some embodiments, the 3-TPS includes a semiconducting layer with cavity and a 3-TPS element having at least one piezoresistive layer overlapping at least a portion of the cavity and oriented at an angle selected to provide a desired sensitivity for the 3-TPS. The method of measuring a pressure with a 3-TPS is performed with a 3-TPS that includes an input terminal, first and second output terminals, and a 3-TPS element, the 3-TPS element overlapping at least a portion of a cavity at a predetermined angle. The method comprises providing an input signal to the input terminal of the 3-TPS, determining a difference between two output signals from the respective output terminals of the 3-TPS, and correlating the determined difference to a pressure.

Abstract: A fully-functional radio receiver fabricated from a single nanotube is being disclosed. Simultaneously, a single nanotube can perform the functions of all major components of a radio: antenna, tunable band-pass filter, amplifier, and demodulator. A DC voltage source, as supplied by a battery, can power the radio. Using carrier waves in the commercially relevant 40-400 MHz range and both frequency and amplitude modulation techniques, successful music and voice reception has been demonstrated. Also disclosed are a radio transmitter and a mass sensor using a nanotube resonator device.

Abstract: In an ultrasound probe (2) and a method for manufacturing the ultrasound probe (2) of the invention, an organic piezoelectric element (21) has a sheet-like form, and is directly or indirectly laminated on a part or the entirety of a plurality of inorganic piezoelectric elements (22). Accordingly, the ultrasound probe (2) can be manufactured with a less number of steps. An ultrasound diagnostic apparatus of the invention includes the ultrasound probe (2). Accordingly, the cost of the ultrasound diagnostic apparatus can be reduced.

Abstract: Resonant sensors, preferably having floating bilayer symmetry, and their methods of use is determining the presence, amount or binding kinetics of an analyte of interest in a test sample are disclosed. The test sample may be a liquid or gas.

Abstract: Systems and methods for identifying problems with PZT elements of micro-actuators are provided. In certain example embodiments, a voltage (e.g., a sine voltage) may be applied to a reference unit causing it as well as a test unit to vibrate. Characteristics of the respective resonances (e.g., frequency, amplitude, phase, etc.) may be compared (e.g., by a processor) to determine whether there are problems with the test unit. The reference unit may include an HGA or an HSA of a hard disk drive device. The test unit may include corresponding parts for inspection. Such techniques make it possible to detect problems with PZT elements when there is only one PZT element per micro-actuator.

Abstract: A spectrum analyzer includes an array of frequency-selective bulk acoustic wave (BAW) resonators each tuned to a predetermined different resonant frequency. The spectrum analyzer further includes a broadband BAW resonator that generates acoustic energy when connected to a signal source. An acoustic coupling transmits the acoustic energy generated by the broadband BAW resonator to the frequency-selective BAW resonators so that one of the frequency-selective BAW resonators will generate an electrical output signal if the acoustic energy transmitted from the broadband BAW resonator contains spectral components at its predetermined resonant frequency.

Abstract: A sensor readout circuit which provides a frequency signal output including a phase detector circuit responsive to an output signal from a sensor and an input signal to the sensor and configured to detect the phase difference between the input signal and the output signal, and a drive circuit responsive to the phase detector circuit and configured to maintain a fixed phase difference between the input signal and the output signal.

Abstract: A test device and method for testing one of a disk drive microactuator and a disk drive sensor that includes two piezoelectric elements. The test device includes a signal generator, signal analyzer, and a user interface. The test device is operational to provide a reference signal (e.g. an electrical signal) to one of the piezoelectric elements in the microactuator and obtain a test measure from the other one of the piezoelectric elements. The test measure is then utilized to assess a performance parameter for the microactuator. The test measure is generated by the other one of the piezoelectric elements in response to the reference signal provided to the first one of the piezoelectric elements.

Abstract: An apparatus for detecting currents in a three-phase power transmission system includes a first detection circuit electrically coupled to a first phase of the three-phase transmission system, a second detection circuit electrically coupled to a second phase of the three-phase transmission system different than the first phase, and an event output switch electrically coupled to the first detection circuit and the second detection circuit and configured to actuate when a subsynchronous current at least one of the first phase and the second phase exceeds a pre-selected subsynchronous current setpoint.

Abstract: The present invention provides instruments and methods for screening combinatorial libraries that addresses many of the problems encountered when using conventional instruments. For example, the disclosed instruments can measure mechanical properties of library members in rapid serial or parallel test format, and can perform tests on small amounts of material, which are easily prepared or dispensed using art-disclosed liquid or solid handling techniques. Compared to conventional instruments, the disclosed instruments afford faster sample loading and unloading, for example, through the use of disposable libraries of material samples.

Abstract: The effects of electromigration have been shown to lead to damage of metal electrodes of electronic devices such as thin film resonator (TFR) devices in only a few hours, for a test input power that is within the operational range of these devices. It has been determined that this failure is sensitive to the frequency of the input power. The present invention provides a method and apparatus for determining high power reliability in electronic devices, so as to enable an accurate determination of the failure time of the electronic device, and hence projected lifetime. This determination is independent from the frequency of an input power applied to the electronic device as part of the method for testing the device. Based on the above results, a TFR device has been developed, which includes a protective or electromigration-reducing layer such as titanium being deposited atop an electrode of the device.

Abstract: The present invention provides instruments and methods for screening combinatorial libraries that addresses many of the problems encountered when using conventional instruments. For example, the disclosed instruments can measure mechanical properties of library members in rapid serial or parallel test format, and can perform tests on small amounts of material, which are easily prepared or dispensed using art-disclosed liquid or solid handling techniques. Compared to conventional instruments, the disclosed instruments afford faster sample loading and unloading, for example, through the use of disposable libraries of material samples.

Abstract: A mechanical-force sensor includes two piezoelectric vibrators which are arranged such that stresses in mutually opposite directions are applied thereto by a mechanical force such as an acceleration. A current-voltage converter and signal-summing circuit converts current signals that flow through the two piezoelectric vibrators into voltage signals. A voltage-amplifier and amplitude limiter circuit amplifies a sum signal of the two voltage signals, and provides a positive feedback of a voltage signal that is in phase with the current signals, thereby causing an oscillating operation. A phase difference-voltage converter circuit generates a voltage signal that is proportional to the phase difference between the voltage signals yielded by the conversion. An amplifier and filter circuit DC-amplifies the voltage signal and removes unwanted frequency components therefrom.

Abstract: Methods are included for determining deviations from &phgr;=0° in test resonators based on the quasi-pure modes' displacement ratio variations with &phgr; angle. A direct relationship between deviation from &phgr;=0° and the c-mode displacement ratio has been observed, so that the larger the deviation from &phgr;=0°, then the larger is the change in the normalized frequency of the c-mode upon immersion in, or contact with, a fluid. The method includes measuring &thgr; and &phgr; angles in reference resonators with different small &phgr; angles and quasi-pure mode frequencies of reference resonators in both air and a test fluid at ambient temperatures, calculating the normalized frequency changes between the air and fluid measurements as a reference point, measuring the test resonator in air then in the fluid and comparing the results.

Abstract: A method for measuring harmonic load-pull including supplying a fundamental frequency signal to a frequency multiplication device under test and obtaining a target even-order multiplied frequency signal. The fundamental load impedance and an even-harmonic load impedance are independently controlled with a load mechanical tuner having an open-ended stub that is one-quarter wavelength long at the fundamental frequency and satisfies a short-circuit condition with respect to the fundamental signal. A fundamental source impedance and an even-harmonic source impedance of an input signal applied to the device under test are independently controlled with a source mechanical tuner having a short-circuit stub that is one-quarter wavelength long at the fundamental frequency and satisfies a short-circuit condition with respect to even-harmonics.

Abstract: The present invention relates to a measuring device and a method for contactless detection of an angle of rotation or a torsional rotation. The measuring device includes a first resonator (2) and a second resonator (4). The two resonators (2, 4) have an essentially circular circumference, on which at least one protrusion and/or one recess is disposed. The two resonators (2, 4) are coplanar to one another and are also rotatable relative to one another. In addition, an exciter device (6) for exciting the resonators and a receiver device (6) for measuring a backscattered signal are present. Upon a relative rotation of the two resonators (2, 4) to one another, the resonant frequency changes, which is used as a measure for ascertaining the angle of rotation.

Abstract: An apparatus using a resonator probe for determining an electronic property of a conductor across a dielectric. The apparatus has a device for inducing lateral mechanical oscillations of the resonator probe and a voltage source for producing a voltage difference between the resonator probe and the conductor to create an electronic drag between the conductor and resonator probe, thus damping the mechanical oscillations of the probe. The electronic property, such as charge carrier mobility, surface resistance, charge carrier lifetime and the number of charge carriers is determined from the damping experienced by the probe.

Abstract: A piezoactuator has a diaphragm, and the diaphragm has flat piezoelectric elements that oscillate in a longitudinal oscillation mode and a sinusoidal oscillation mode. A first electrode for detecting oscillation in the longitudinal oscillation mode, and a second electrode for detecting the amplitude of oscillation in the sinusoidal oscillation mode, are disposed on the surface of the diaphragm. When the piezoactuator is driven with a drive signal, the phase difference of a first detection signal output from the first electrode and a second detection signal output from the second electrode is detected. The frequency at which the detected phase difference becomes the maximum phase difference is then obtained, and a drive signal of a matching frequency is applied to the piezoelectric elements.

Abstract: Redundant rate sensor and method in which inertial rate is monitored with a plurality of vibratory sensing elements mounted in a single enclosure, signals from the sensing elements are processed to provide an independent rate output signal for each of the sensing elements, and the independent rate output signals are delivered to a connector which is accessible externally of the enclosure.

Abstract: A resonator device utilizes two small mechanical resonators that are electrostatically coupled. A first resonator receives an input signal near its resonant frequency, and the input signal and a second signal are summed and provided to a second resonator. The resonant frequency of the second resonator is approximately equal to the second signal frequency. A width of response of the amplifier is tuned by varying the pump voltage. Resonant frequencies of corresponding individual oscillators are tuned by adjusting bias voltages.

Abstract: Redundant rate sensor and method in which inertial rate is monitored with a plurality of vibratory sensing elements mounted in a single enclosure, signals from the sensing elements are processed to provide an independent rate output signal for each of the sensing elements, and the independent rate output signals are delivered to a connector which is accessible externally of the enclosure.

Abstract: An acceleration sensor includes a bimorph type acceleration detection element including a first resonator and a second resonator, each resonator formed of a piezoelectric body and having electrodes arranged on both main surfaces thereof, and an intermediate layer. The acceleration detection element is produced by bonding the first resonator and the second resonator with the intermediate layer interposed therebetween. The acceleration detection element is supported at one longitudinal end or opposed longitudinal ends thereof so that the first and second resonators are integrally deflected under acceleration. The intermediate layer is hard enough to transfer flexural stress in one of the first and second resonator to the other of the first and second resonators and the vibration of the one of the first and second resonators is attenuated when the vibration is transmitted from the one to the other of the first and second resonators.

Abstract: An electrical circuit having an oscillator and additional structural elements that are connected to the oscillator. In an iterative method, upon variation of circuit parameters of the additional structural elements, the following steps are carried out for each instance of the circuit parameters: a stability analysis of the circuit is carried out for each respective instance, and if the circuit oscillates, a first value is assigned to the instance in a matrix in which all the instances being examined are stored. Otherwise, a second value is assigned to the instance in the matrix.

Abstract: A thermoacoustic driver incorporates a linear electrodynamic motor having electrical terminals and a moving part, a driver suspension housing, a piston, and a stiffness-enhancing device for raising the mechanical resonance frequency of the electrodynamic motor without reducing the piston stroke. The stiffness enhancement is accomplished by the use of specially optimized suspension spring structures and/or by attaching one or more electrical inductors to the electrical terminals of the driver. The stiffness enhancement using mechanical springs incorporates one or more starfish structures extending between the driver suspension housing and the piston and rigidly clamped to both. The starfish structures comprise radially extending legs, which are leaf springs or beams of varying width. The shape of the beams and the shape of the overall spring structure are optimized to enhance flexural or torsional stiffness and relieve arc tension within the constraints of cost-effectiveness.

Abstract: A method is provided for measuring harmonic load-pull for frequency multiplication to obtain a load impedance and a source impedance for which frequency multiplication performance of a frequency multiplication device is optimized. A fundamental frequency signal is supplied to a frequency multiplication device under test from a source measurement system that includes a source mechanical tuner for adjusting a fundamental source impedance of an input signal. A load impedance frequency is obtained at which multiplication performance of the frequency multiplication device is optimum from a load measurement system that includes a load mechanical tuner for adjusting a load impedance of a target even-order multiplied signal among harmonics included in signal output of the frequency multiplication device.

Abstract: A method and apparatus for measuring the frequency of a desired resonant mode of a crystal arrangement, or other two-port device, during an automated operation. The crystal arrangement, or other two-port device, is placed into a test circuit and subjected to a sinusoidal test signal of known frequency. Based upon the output response of the crystal arrangement to the test signal, the frequency of the test signal is changed such that the test signal rapidly converges on a desired mode of operation of the crystal arrangement. This is accomplished by first noting a desired increase in amplitude of the output response of the crystal arrangement, followed by measuring an error signal related to the desired crystal arrangement mode of operation. When the error equals a predetermined value the frequency of the sinusoidal test signal is the frequency of the desired mode.