Abstract: A sensor output compensation circuit includes a differential amplifier circuit to amplify a sensor output that is outputted as a differential voltage between outputs of first and second composite arithmetic circuits, based on predetermined detection voltages measured in detection signal output terminals of two TMR sensors. The two TMR sensors are located at relative positions between which the influence of a residual magnetic field in the TMR sensors is canceled out, and a voltage is applied thereto in opposite directions. The first composite arithmetic circuit adds the detection voltages that are measured in the detection signal output terminals of the two TMR sensors in a first phase. The second composite arithmetic circuit adds the detection voltages that are measured in the detection signal output terminals of the two TMR sensors in a second phase.

Abstract: A sensor output compensation circuit includes a differential amplifier circuit to amplify, as a sensor output, a differential voltage between detection voltages measured in two detection signal output terminals of a sensor including a sensor element that has a resistance value that changes depending on a detected physical quantity and that is connected by bridge connection, a temperature sensor circuit to detect an ambient temperature, and a temperature coefficient sensitivity compensation circuit to apply, to two power terminals of the sensor, a bias voltage to cancel a variation in sensitivity of the sensor output as the ambient temperature changes, based on the ambient temperature that is detected by the temperature sensor circuit.

Abstract: A sensor output compensation circuit includes a linearity compensation circuit to adjust linearity of a sensor output by changing a resistance value of a first variable resistor, a compensation circuit to adjust sensitivity temperature characteristics of a sensor output by changing a resistance value of a second variable resistor, and a compensation circuit to adjust temperature characteristics of an offset voltage of the sensor output by inputting a reference voltage to a reference voltage terminal of an operational amplifier of an amplifier circuit for compensation.

Abstract: A frequency synthesizer includes: an oscillating section that generates a first signal; a frequency ratio measuring section that measures a frequency ratio of the first signal and a second signal by using the first signal and the second signal; a comparing section that compares the frequency ratio, which is measured by the frequency measuring section, with a target value of a frequency ratio; and a filter that is disposed on a preceding stage of the comparing section. A frequency of the first signal of the oscillating section is adjusted on the basis of a comparison result of the comparing section.

Abstract: A frequency synthesizer includes: an oscillating section that generates a first signal; a frequency ratio measuring section that measures a frequency ratio of the first signal and a second signal by using the first signal and the second signal; a comparing section that compares the frequency ratio, which is measured by the frequency measuring section, with a target value of a frequency ratio; and a filter that is disposed on a preceding stage of the comparing section. A frequency of the first signal of the oscillating section is adjusted on the basis of a comparison result of the comparing section.

Abstract: A frequency synthesizer includes: an oscillating section that generates a first signal; a frequency ratio measuring section that measures a frequency ratio of the first signal and a second signal by using the first signal and the second signal; a comparing section that compares the frequency ratio, which is measured by the frequency measuring section, with a target value of a frequency ratio; and a filter that is disposed on a preceding stage of the comparing section. A frequency of the first signal of the oscillating section is adjusted on the basis of a comparison result of the comparing section.

Abstract: A frequency synthesizer includes: an oscillating section that generates a first signal; a frequency ratio measuring section that measures a frequency ratio of the first signal and a second signal by using the first signal and the second signal; a comparing section that compares the frequency ratio, which is measured by the frequency measuring section, with a target value of a frequency ratio; and a filter that is disposed on a preceding stage of the comparing section. A frequency of the first signal of the oscillating section is adjusted on the basis of a comparison result of the comparing section.

Abstract: An MEMS vibrator includes a substrate, a fixation section disposed above a principal surface of the substrate, a support section extending from the fixation section, and a vibrating body (an upper electrode) separated from the substrate and supported by the support section in a node part of a vibration, and the vibrating body is a 2n-fold rotationally symmetric body having 2n beams radially extending from a node part of a vibration, wherein n is a natural number.

Abstract: A physical quantity sensor includes: a diaphragm that can deflect and deform; a peripheral wall portion that is disposed around the diaphragm and has a thickness increasing in a direction away from the diaphragm; a deflection amount sensor that detects a deflection amount of the diaphragm; and a temperature sensor that is disposed in the peripheral wall portion.

Abstract: An MEMS vibrator includes a substrate, a fixation section disposed above a principal surface of the substrate, a support section extending from the fixation section, and a vibrating body (an upper electrode) separated from the substrate and supported by the support section in a node part of a vibration, and the vibrating body is a 2n-fold rotationally symmetric body having 2n beams radially extending from a node part of a vibration, wherein n is a natural number.

Abstract: A MEMS vibration element 100 includes a substrate 1, a fixing part 23 provided on a principal surface of the substrate 1, a supporting part 22 extending from the fixing part 23, and an upper electrode 21 (a vibration body) supported by the supporting part 22, isolated from the substrate 1. The upper electrode 21 includes a cut section extending from the peripheral portion of the upper electrode 21 toward the central portion of the upper electrode 21, the cut section 30 exposing a side surface portion of the upper electrode 21. The upper electrode 21 includes a joining part provided at a side surface portion 31 oriented in a direction from the central portion toward the peripheral portion, among the side surface portion exposed by the cut section 30, and the joining part is connected to the supporting part 22.

Abstract: A MEMS vibration element 100 includes a substrate 1, fixing parts 23 provided on a principal surface of the substrate 1, supporting parts (supporting beams 22 and connection beams 21) extending from the fixing parts 23, and an upper electrode (a vibration body) supported by the supporting parts, isolated from the substrate 1. The upper electrode 20 includes cut sections 30 each extending from the peripheral portion of the upper electrode 20 toward the central portion of the upper electrode 20, the cut sections 30 exposing side surfaces 31 of the upper electrode 20. The upper electrode 20 includes joining parts provided at the side surfaces 31 oriented in a direction from the peripheral portion toward the central portion of the upper electrode 20, and the joining parts are connected to the supporting parts 22.

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 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: 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: An oscillator includes: a substrate; a reference oscillation circuit including a first MEMS oscillator disposed above the substrate, the reference oscillation circuit outputting a first oscillation signal; at least one voltage-controlled oscillation circuit including a second MEMS oscillator disposed above the substrate, the oscillation frequency of the at least one voltage-controlled oscillation circuit being controlled based on a control signal, the at least one voltage-controlled oscillation circuit outputting a second oscillation signal; a frequency division circuit dividing the frequency of the second oscillation signal and outputting a frequency division signal; and a phase-comparison circuit outputting the control signal based on a phase difference between the frequency division signal and the first oscillation signal, wherein the first MEMS oscillator and the second MEMS oscillator each have a first electrode and a second electrode, the second electrode has a movable part disposed so as to face the fi

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 oscillator circuit includes a first terminal, a second terminal, a resonator that is connected to the first terminal and the second terminal, a first capacitor that is connected to the first terminal and a ground line supplying the ground electric potential, a second capacitor that is connected to the second terminal and the ground line, m inverters, where m is an odd number equal to or larger than three, which are connected in series between the first terminal and the second terminal, and a third capacitor that is connected to an input terminal of the n-th (where n is an integer satisfying 1?n<m) inverter, counted from an input side of the inverter array and an output terminal of the (n+1)-th inverter.

Abstract: An oscillation circuit includes a cross-coupled circuit having a first active element and a second active element which are differentially connected to each other. The oscillation circuit oscillates in a resonance frequency of a resonator connected between the first active element and the second active element.

Abstract: A surface acoustic wave oscillator includes: a cross-coupled circuit including first and second active elements differentially connected to first and second output terminals; first and second surface acoustic wave elements having different resonance frequencies and connected to the cross-coupled circuit in parallel; a first variable capacitance circuit including a first variable capacitance element and changing the resonance frequency of the first surface acoustic wave element; and a second variable capacitance circuit including a second variable capacitance element and changing the resonance frequency of the second surface acoustic wave element, wherein the first surface acoustic wave element is connected to the first variable capacitance circuit, the second surface acoustic wave element is connected to the second variable capacitance circuit, and oscillating outputs from combining outputs of the first and second surface acoustic wave elements are outputted by the cross-coupled circuit.