Abstract: A method is provided for tuning a microelectromechanical systems (MEMS) oscillator comprising an acoustic resonator and a tuning and amplification circuit arranged in a loop. The method comprises determining an initial oscillation frequency of the oscillator, modifying a capacitance of the tuning and amplification circuit according to the initial oscillation frequency, and adjusting a power level of the oscillator according to the modified capacitance.

Abstract: An oscillation apparatus comprising: a frame; a first proof mass coupled to the frame via a spring; a driving circuit operatively coupled to the first proof mass and the frame, wherein the driving circuit is configured to induce oscillatory motion of the first proof mass relative to the frame at a resonant frequency in a first direction; a first electron-tunneling position switch operatively coupled to the first proof mass such that the first position switch is configured to pass through a closed state during each oscillation of the proof mass, wherein the position switch comprises first and second single-atom-thick tunneling electrodes; and a sensing circuit coupled to the position switch, the sensing circuit configured to output a signal whenever the position switch passes through the closed state.

Abstract: A method of configuring a device comprising a MEMS resonator includes initiating operation of the device, estimating a first parameter of the MEMS resonator based on the initiated operation, the first parameter not varying with the bias voltage, monitoring the operation of the device at a plurality of levels of the bias voltage, calculating a second parameter of the MEMS resonator based on the monitored operation, the second parameter varying with the bias voltage, determining an operational level of the bias voltage based on the estimated first parameter and the calculated second parameter, and configuring the device in accordance with the determined operational level of the bias voltage.

Abstract: A MEMS device and method for amplitude regulation of a MEMS device are disclosed. In a first aspect, the MEMS device comprises a MEMS resonator, a limiter coupled to the MEMS resonator, and a regulator coupled to the limiter. The MEMS device includes an amplitude control circuit coupled to the MEMS resonator. The amplitude control circuit controls a supply of the limiter via the regulator to regulate oscillation loop amplitude of the MEMS device. In a second aspect, the method includes coupling a regulator to the limiter, coupling an amplitude control circuit to the MEMS resonator, and controlling a supply of the limiter via the regulator to regulate oscillation loop amplitude of the MEMS device.

Abstract: A periodic signal generator is configured to generate high frequency signals characterized by relatively low temperature coefficients of frequency (TCF). This generator may include an oscillator containing a pair of equivalent MEMs resonators therein, which are configured to support bulk acoustic wave and surface wave modes of operation at different resonance frequencies. Each resonator includes a stack of layers including a semiconductor resonator body (e.g., Si-body), a piezoelectric layer (e.g., AIN layer) on the resonator body and interdigitated drive and sense electrodes on the piezoelectric layer. The oscillator is configured to support the generation of first and second periodic signals having unequal first and second frequencies (f1, f2) from first and second resonators within the pair. These first and second periodic signals are characterized by respective first and second temperature coefficients of frequency (TCf1, TCf2), which may differ by at least about 10 ppm/° C.

Abstract: A microelectromechanical system (MEMS) device includes a resonator anchored to a substrate. The resonator includes a first strain gradient statically deflecting a released portion of the resonator in an out-of-plane direction with respect to the substrate. The resonator includes a first electrode anchored to the substrate. The first electrode includes a second strain gradient of a released portion of the first electrode. The first electrode is configured to electrostatically drive the resonator in a first mode that varies a relative amount of displacement between the resonator and the first electrode. The resonator may include a resonator anchor anchored to the substrate. The first electrode may include an electrode anchor anchored to the substrate in close proximity to the resonator anchor. The electrode anchor may be positioned relative to the resonator anchor to substantially decouple dynamic displacements of the resonator relative to the electrode from changes to the substrate.

Abstract: A resonator element includes a base section, a pair of vibrating arms projecting toward the same side from the base section, and disposed side by side in a predetermined direction, a support arm projecting from the base section toward the same side as the pair of vibrating arms, disposed between the pair of vibrating arms, and having a recessed portion disposed on one principal surface, and a first electrically-conductive pad and a second electrically-conductive pad disposed side by side across the recessed portion.

Abstract: An electronic device includes a substrate, a cavity part formed above the substrate with a functional device placed therein, a coating structure that defines the cavity part, and the coating structure has a first surrounding wall formed around the cavity part above the substrate, a second surrounding wall formed around the cavity part above the first surrounding wall, a coating layer that defines an upper surface of the cavity part, wherein the second surrounding wall is located inside the first surrounding wall in a plan view.

Abstract: A method of manufacturing a MEMS resonator formed from a first material having a first Young's modulus and a first temperature coefficient of the first Young's modulus, and a second material having a second Young's modulus and a second temperature coefficient of the second Young's modulus, a sign of the second temperature coefficient being opposite to a sign of the first temperature coefficient at least within operating conditions of the resonator. The method includes the steps of forming the resonator from the first material; applying the second material to the resonator; and controlling the quantity of the second material applied to the resonator by the geometry of the resonator.

Abstract: Provided is a piezoelectric oscillator to attain high-frequency performance and frequency stabilization with the use of reflection characteristics of a reflective element. A piezoelectric oscillator is configured such that: a resonant circuit is connected to a gate of a field effect transistor; an output terminal is connected to a drain and a power supply voltage V is applied to the drain; a piezoelectric resonator is connected to a source, as a reflective element; and a resonance frequency of the resonant circuit and an oscillation frequency of the piezoelectric resonator as a reflective element are set to substantially the same frequency, and further, the piezoelectric oscillator may be configured such that a first matching circuit is provided between the resonant circuit and the gate, a second matching circuit is provided between the drain and the output terminal, and a third matching circuit is provided between the source and the reflective element.

Abstract: An oscillation circuit includes a plurality of MEMS vibrators each having a first terminal and a second terminal, and having respective resonant frequencies different from each other, an amplifier circuit (an inverting amplifier circuit) having an input terminal and an output terminal, and a connection circuit adapted to connect the first terminal of one of the MEMS vibrators and the input terminal to each other, and the second terminal of the MEMS vibrator and the output terminal to each other to thereby connect the one of the MEMS vibrators and the amplifier circuit (the inverting amplifier circuit) to each other.

Abstract: An ovenized micro-electro-mechanical system (MEMS) resonator including: a substantially thermally isolated mechanical resonator cavity; a mechanical oscillator coupled to the mechanical resonator cavity; and a heating element formed on the mechanical resonator cavity.

Abstract: An oscillating circuit for determining a resonant frequency of an electro-mechanical oscillating device and for driving the electro-mechanical oscillating device at the determined resonant frequency includes a driving circuit and a start-up, impetus injection circuit. The driving circuit is configured to receive one or more reference signals and further configured to provide a driving signal related to the reference signals to the electro-mechanical oscillating device. The start-up, impetus injection circuit is operably coupled to the electro-mechanical oscillating device and configured to selectively provide a start-up excitation signal to the electro-mechanical oscillation device. The start-up, impetus injection circuit is activated upon start-up of the oscillating circuit to drive the electro-mechanical oscillation device and the driving circuit determines a resonant frequency by measuring a parameter related to the resonant frequency of the electro-mechanical oscillating device.

Abstract: An oscillator includes: a plurality of MEMS vibrators each having a first terminal and a second terminal, and having respective resonant frequencies different from each other; an amplifier circuit having an input terminal and an output terminal; a connection circuit adapted to connect the first terminal of one of the MEMS vibrators and the input terminal to each other, and the second terminal of the one of the MEMS vibrators and the output terminal to each other; a signal reception terminal adapted to receive a switching signal used to switch a state of the connection circuit; and a switching circuit adapted to make the connection circuit switch the MEMS vibrator to be connected to the amplifier circuit based on the switching signal, wherein the MEMS vibrators are housed in an inside of a cavity, and the signal reception terminal is disposed outside the cavity.

Abstract: A MEMS resonator system that reduces interference signals arising from undesired capacitive coupling between different system elements. The system, in one embodiment, includes a MEMS resonator, electrodes, and at least one resonator electrode shield. In certain embodiments, the resonator electrode shield ensures that the resonator electrodes interact with either one or more shunting nodes or the active elements of the MEMS resonator by preventing or reducing, among other things, capacitive coupling between the resonator electrodes and the support and auxiliary elements of the MEMS resonator structure. By reducing the deleterious effects of interfering signals using one or more resonator electrode shields, a simpler, lower interference, and more efficient system relative to prior art approaches is presented.

Abstract: Micromechanical resonating devices, as well as related methods, are described herein. The resonating devices can include a micromechanical resonating structure, an actuation structure that actuates the resonating structure, and a detection structure that detects motion of the resonating structure. A bias structure separated from the mechanical resonating structure is provided to tune a resonance frequency of the mechanical resonating structure.

Abstract: Methods of testing packaged thin-film piezoelectric-on-semiconductor (TPoS) microelectromechanical resonators having hermetic seals include measuring a quality factor (Q) of resonance of the packaged resonator at at least two unequal temperatures to determine whether a ?Q/?T is significantly different (e.g, by at least 50%) over a temperature range (?T) spanning a smallest and largest of the at least two temperatures. These measurements are performed for a packaged resonator having a QAIR<QTED, where QAIR is the quality factor of resonance of the packaged resonator due to air damping and QTED is the quality factor of resonance of the packaged resonator due to thermoelastic damping.

Abstract: Provided is an oscillator including a piezoelectric vibrator (10), a vibration member (20) that constrains the piezoelectric vibrator (10) on one surface thereof, an elastic member (40) that is provided on one surface of the vibration member (20) or the other surface opposite to one surface and provided so as to be located between edges of the piezoelectric vibrator (10) and the vibration member (20) when seen in a plan view, a fixing member (42) that is provided on one surface or the other surface of the vibration member (20) and provided so as to be located between the piezoelectric vibrator (10) and the elastic member (40) when seen in a plan view, and a supporting member (30) that supports the vibration member (20) through the elastic member (40) and the fixing member (42).

Abstract: Provided is an oscillator (100) including a piezoelectric body (70) that has a plurality of protrusions (72) on one surface thereof, a plurality of electrodes (80) that are respectively provided on the plurality of protrusions (72) so as to be separated from each other, and a plurality of electrodes (82) that are provided on the other surface opposite to the one surface of the piezoelectric body (70) so that each of the electrodes faces only one electrode (80). Thus, it is possible to prevent variation in acoustic characteristics from occurring. Therefore, the oscillator capable of improving the acoustic characteristics of an electronic device is provided.

Abstract: A MEMS circuit comprises a MEMS device arrangement with temperature dependent output; a resistive heating circuit; and a feedback control system for controlling the resistive heating circuit to provide heating in order to maintain a MEMS device at a constant temperature. The heating is controlled in dependence on the ambient temperature, such that a MEMS device temperature is maintained at one of a plurality of temperatures in dependence on the ambient temperature. This provides power savings because the temperature to which the MEMS device is heated can be kept within a smaller margin of the ambient temperature.

Abstract: A micromechanical component and a method for providing the oscillation excitation of an oscillation element of a micromechanical component, the micromechanical component having a frame, which is connected to a carrier substrate by an outer suspension element, in which the frame being tiltable about a first axis and oscillatory about a second axis that is positioned perpendicular to the first axis, and in which the micromechanical component having an oscillation element that is connected to the frame by an inner suspension element, and is tiltable about the second axis, the outer suspension element being provided to be dimensioned in such a way that a first oscillation of the frame about the second axis and a second oscillation of the oscillation element about the second axis have a maximum coupling.

Abstract: This invention provides a micromechanical resonator oscillator structure and a driving method thereof. As power handling ability of a resonator is proportional to its equivalent stiffness, a better power handling capability is obtained by driving a micromechanical resonator oscillator at its high equivalent stiffness area. One of the embodiments of this invention is demonstrated by using a beam resonator. A 9.7-MHZ beam resonator via the high-equivalent stiffness area driven method shows better power handling capability and having lower phase noise.

Abstract: A driver circuit includes a comparator (drive signal generation section) that generates a drive signal based on a signal obtained by converting an oscillation current of a vibrator that has been input via a first signal line into a voltage using an I/V conversion circuit (current/voltage conversion section), and supplies the drive signal to the vibrator via a second signal line, an oscillation detection circuit (oscillation detection section) that detects whether or not the oscillation current has reached a predetermined value after the vibrator has started to oscillate, a startup oscillation circuit (startup oscillation section) that assists an oscillation operation of the vibrator until the oscillation current reaches the predetermined value, and a switch that separates a capacitor from the second signal line until the oscillation current reaches the predetermined value, and connects the capacitor to the second signal line when the oscillation current has reached the predetermined value.

Abstract: A method of actuating a system comprising a movable component and an actuator configured to move the movable component comprises providing a control signal representative of a desired motion of the movable component. The control signal is supplied to one or more resonators. Each of the one or more resonators has a mode of oscillation representative of at least one elastic mode of oscillation of the system. The control signal is modified by subtracting from the control signal a signal representative of a response of the one or more resonators to the control signal. The actuator is operated in accordance with the modified control signal. Thus, undesirable elastic oscillations of the system which might occur if the system were operated with the original control system can be reduced.

Abstract: Systems and methods for operating with oscillators configured to produce an oscillating signal having an arbitrary frequency are described. The frequency of the oscillating signal may be shifted to remove its arbitrary nature by application of multiple tuning signals or values to the oscillator. Alternatively, the arbitrary frequency may be accommodated by adjusting operation one or more components of a circuit receiving the oscillating signal.

Abstract: The present invention relates to a pressure sensor, which may include a first electrode plate, a second electrode plate, a third electrode plate, a fourth electrode plate and a fifth electrode plate, which are successively laminated on a substrate, wherein the first electrode plate, the third electrode plate and the fourth electrode plate are fixed to the substrate, the first electrode plate and the second electrode plate are disposed opposite to each other and have a gap formed therebetween, the second electrode plate is suspended over the first electrode plate to constitute a first capacitor; the second electrode plate and the third electrode plate are disposed opposite to each other and have a gap formed therebetween, to constitute a second capacitor; and the fifth electrode plate is suspended over the fourth electrode plate to constitute a third capacitor, and can move along a direction perpendicular to the substrate.

Abstract: MEMS oscillators, which include a silicon-type, in particular piezoresistive resonators, can be used to provide a fixed, stable output frequency. Silicon has a natural temperature dependence of Young's modulus, therefore, as ambient temperature changes and/or the piezoresistive resonator is powered, the resonator temperature changes, and the resonance frequency of the resonator drifts. In order to account for the temperature drift of the piezoresistive resonator, the piezoresistive resonator itself is used as a temperature sensor. The relative resistance change of the piezoresistive resonator depends only on the relative temperature change and material property of the resonator. Therefore, an accurate temperature can be sensed directly on the piezoresistive resonator. The temperature drift information is provided to a frequency adjuster, which corrects the output frequency of the circuit.

Abstract: Microelectromechanical resonators include a resonator body with a built-in piezoelectric-based varactor diode. This built-in varactor diode supports passive frequency tuning by enabling low-power manipulation of the stiffness of a piezoelectric layer, in response to controlling charge build-up therein at resonance. A resonator may include a composite stack of a bottom electrode, a piezoelectric layer on the bottom electrode and at least one top electrode on the piezoelectric layer. The piezoelectric layer includes a built-in varactor diode, which is defined by at least two regions having different concentrations of electrically active dopants therein.

Abstract: A MEMS oscillator having a feedback-type oscillation circuit including a MEMS resonator and an amplifier, a voltage control unit operable to control a bias voltage applied to an oscillating member of the MEMS resonator, and an auto gain control unit which receives an output from the amplifier and, based on a level of the output, to output an amplitude control signal for controlling a gain of the amplifier to the amplifier such that the level of the output from the amplifier comes to be a predetermined level, wherein the voltage control unit controls the bias voltage applied to the oscillating member based on an operating temperature of the MEMS resonator such that a peak gain of the MEMS resonator comes to have a predetermined value regardless of the operating temperature, and the voltage control unit derives the operating temperature of the MEMS resonator by monitoring the amplitude control signal.

Abstract: A piezoresistive MEMS oscillator uses an output circuit to control the voltage across the resonator body. This results in a DC bias of the resonator. A current path is provided between the output of the output circuit and the resonator body, such that changes in current through or voltage across the resonator body, resulting from changes in resistance of the resonator body, are coupled to the output. This arrangement uses the bias current flowing through the resonator to derive the output. In this way, the same DC current is used to provide the required DC resonator bias and to drive the output circuit to its DC operating point.

Abstract: A semiconductor integrated circuit capable of reliably detecting oscillation stop of a vibrator-type oscillation circuit and reliably restarting the oscillation circuit when oscillation stop is detected is provided. The semiconductor integrated circuit includes one or more main oscillation circuits configured to generate a main clock signal by a vibrator, a ring oscillator configured to always operate independently of the main oscillation circuit, a main clock detection circuit configured to monitor the main clock signal on the basis of an output clock signal of the ring oscillator and to determine an operation state of the main oscillation circuit, and an switch circuit configured to switch a combination of elements making up the main oscillation circuit in response to a detection result of the main clock detection circuit.

Abstract: A MEMS resonator including: an input port which is applied with an input voltage; an output port which outputs an output current; and N MEMS resonating units (N being an integer greater than or equal to 2), the MEMS resonating unit each including a vibrator and being connected to the input port and output port, in which the N MEMS resonating units are serially connected to the input port.

Abstract: A resonator includes a CMOS substrate having a first electrode and a second electrode. The CMOS substrate is configured to provide one or more control signals to the first electrode. The resonator also includes a resonator structure including a silicon material layer. The resonator structure is coupled to the CMOS substrate and configured to resonate in response to the one or more control signals.

Abstract: A MEMS oscillator including: an oscillator unit being capable of outputting an output from an amplifier as an original oscillator signal that includes a feedback type oscillator circuit including a MEMS resonator and an amplifier, and an automatic gain controller receiving the output from the amplifier and controlling a gain of the amplifier based on a level of the output to maintain a level of the output from the amplifier constant; and a corrector unit that receives the original oscillator signal, that generates from the original oscillator signal a signal of a predetermined set frequency, and that outputs the generated signal of the predetermined set frequency as an output signal.

Abstract: A method of multi-stage substrate etching and a terahertz oscillator manufactured by using the method are provided. The method comprises the steps of forming a first mask pattern on any one surface of a first substrate, forming a hole by etching the first substrate using the first mask pattern as an etching mask, bonding, to the first substrate, a second substrate having the same thickness as a depth to be etched, forming a second mask pattern on the second substrate bonded, forming a hole by etching the second substrate using the second mask pattern as an etching mask, and removing an oxide layer having the etching selectivity between the first substrate and the second substrate.

Abstract: A crystal oscillator and manufacturing method thereof are provided.

Abstract: Techniques are generally described for low average power communications that can be used for communications between one or more bionic implants and/or one or more control units. Bionic implants and/or control units can be adapted to provide stimulus control and/or sensory or other feedback back from the bionic implants. An example system may include implant devices configured to exchange brief messages between other devices. Some examples may rely on coarse message timing that can be derived from a quartz tuning fork type of resonator. Carrier frequency control can be derived from an on-chip MEMS resonator adapted for high frequency use. An electrical stimulation power supply in each implant can be configured for use in nerve/muscle excitation and/or as a polarizing voltage source for the MEMS resonator. Various compensation mechanisms are described that can be used to compensate for the imprecise and/or temperature dependent frequency in the MEMS resonator.

Abstract: Doubly-clamped nanowire electromechanical resonators that can be used to generate parametric oscillations and feedback self-sustained oscillations. The nanowire electromechanical resonators can be made using conventional NEMS and CMOS fabrication methods. In very thin nanowire structures (sub-micron-meter in width), additive piezoresistance patterning and fabrication can be highly difficult and thus need to be avoided. This invention shows that, in piezoresistive nanowires with homogeneous material composition and symmetric structures, no conventional and additive piezoresistance loops are needed. Using AC and DC drive signals, and bias signals of controlled frequency and amplitude, output signals having a variety of frequencies can be obtained. Various examples of such resonators and their theory of operation are described.

Abstract: A method of operating a micro-electromechanical system, comprising a resonator; an actuation electrode; and a first detection electrode, to filter and mix a plurality of signals. The method comprises applying a first alternating voltage signal to the actuation electrode, wherein an actuation force is generated having a frequency bandwidth that is greater than and includes a resonant bandwidth of a mechanical frequency response of the resonator, and wherein a displacement of the resonator is produced which is filtered by the mechanical frequency response and varies a value of an electrical characteristic of the first detection electrode. The method also comprises applying a second alternating voltage signal to the first detection electrode, wherein the second voltage signal is mixed with the varying value to produce a first alternating current signal. The first alternating current signal is detected at the first detection electrode.

Abstract: A microelectromechanical device includes a body, a movable mass, elastically connected to the body and movable in accordance with a degree of freedom, and a driving device, coupled to the movable mass and configured to maintain the movable mass in oscillation at a steady working frequency in a normal operating mode. The microelectromechanical device moreover includes a start-up device, which is activatable in a start-up operating mode and is configured to compare a current oscillation frequency of a first signal correlated to oscillation of the movable mass with a reference frequency, and for deciding, on the basis of the comparison between the current oscillation frequency and the reference frequency, whether to supply to the movable mass a forcing signal packet so as to transfer energy to the movable mass.

Abstract: Devices having piezoelectric material structures integrated with substrates are described. Fabrication techniques for forming such devices are also described. The fabrication may include bonding a piezoelectric material wafer to a substrate of a differing material. A structure, such as a resonator, may then be formed from the piezoelectric material wafer.

Abstract: A MEMS oscillator includes a resonator body and primary and secondary drive electrodes to electrostatically drive the resonator body. Primary and secondary sense electrodes sense motion of the resonator body. The primary and secondary drive and sense electrodes are configured to be used together during start-up of the MEMS oscillator. The secondary drive electrode and secondary sense electrode are disabled after start-up, while the primary drive and sense electrodes remain enabled to maintain oscillation.

Abstract: The present invention is a method for reducing phase noise in oscillator signals. For example, the oscillator may be a low phase noise MEMS-based oscillator and may include a resonator (ex.—a MEMS resonator). Further, the resonator of the oscillator may be operated near a bifurcation point. Still further, the MEMS resonator may be parametrically pumped in such a way so as to redistribute the quadrature signal noise (ex.—phase noise) to in-phase noise (ex.—amplitude noise).

Abstract: A MEMS oscillator having a feedback-type oscillation circuit including a MEMS resonator and an amplifier, a voltage control unit operable to control a bias voltage applied to an oscillating member of the MEMS resonator, and an auto gain control unit which receives an output from the amplifier and, based on a level of the output, to output an amplitude control signal for controlling a gain of the amplifier to the amplifier such that the level of the output from the amplifier comes to be a predetermined level, wherein the voltage control unit controls the bias voltage applied to the oscillating member based on an operating temperature of the MEMS resonator such that a peak gain of the MEMS resonator comes to have a predetermined value regardless of the operating temperature, and the voltage control unit derives the operating temperature of the MEMS resonator by monitoring the amplitude control signal.

Abstract: A hybrid system having a non-MEMS device and a MEMS device is described. The apparatus includes a non-MEMS device and an integrated circuit including a MEMS device, the integrated circuit formed on a substrate. The integrated circuit includes a control circuit for the non-MEMS device and a MEMS control circuit for the MEMS device.

Abstract: A piezoresistive MEMS oscillator comprises a resonator body, first and second drive electrodes located adjacent the resonator body for providing an actuation signal; and at least a first sense electrode connected to a respective anchor point. The voltages at the electrodes are controlled and/or processed such that the feedthrough AC current from one drive electrode to the sense electrode is at least partially offset by the feedthrough AC current from the other drive electrode to the sense electrode.

Abstract: A dual in-situ mixing approach for extended tuning range of resonators. In one embodiment, a dual in-situ mixing device tunes an input radio-frequency (RF) signal using a first mixer, a resonator body, and a second mixer. In one embodiment, the first mixer is coupled to receive the input RF signal and a local oscillator signal. The resonator body receives the output of the first mixer, and the second mixer is coupled to receive the output of the resonator body and the local oscillator signal to provide a tuned output RF signal as a function of the frequency of local oscillator signal.

Abstract: Methods and apparatus for tuning devices having resonators are described. Phase shifters are included in the circuits and used to shift the phase of the output signal(s) of the resonators. In some implementations, the phase shifters are configured in a feedback loop with the resonators. One or more of the apparatus described herein may be implemented as part, or all, of a microelectromechanical system (MEMS).

Abstract: Self powered microelectromechanical oscillators are provided for various applications.

Abstract: Provided is an oscillator using an MEMS resonator, which can reduce an influence of noise of a TIA and improve phase noise characteristics of an oscillator output. The oscillator includes an MEMS resonator, a TIA, a buffer amplifier, and a current/voltage converter that couples, by electromagnetic induction, with a wiring line via which an output of the MEMS resonator is fed to the TIA, so as to convert a current flowing in the wiring line to a voltage and output the voltage to the buffer amplifier. Thus, the oscillator output is extracted from the current/voltage converter. Further, the current/voltage converter is provided in the form of an oscillation output coil provided so as to surround the wiring line in a noncontact manner, in which oscillation output coil one end is connected to ground and the other end is connected to the buffer amplifier.