Abstract: An integrated circuit includes a memory and peripheral circuits with a temperature sensor used to automatically adjust operating voltages. The temperature sensor includes a reference circuit that generates a first reference with a first non-zero temperature coefficient and a second reference with a second temperature coefficient having a different magnitude than the first non-zero temperature coefficient. A detector circuit on the integrated circuit, having temperature and process variation compensation, converts a difference between the first and second references into a digital signal indicating temperature on the integrated circuit.

Abstract: A circuit device includes a first terminal, a first oscillation circuit oscillating a resonator and generating a first voltage for automatic gain control for controlling amplitude of a signal output from the resonator, a digital signal generation circuit generating a digital signal corresponding to the first voltage, and a first interface circuit outputting the digital signal to the first terminal.

Abstract: A passive radio frequency identification (RFID) reader is configured to dynamically vary the Q factor of its resonant antenna coil circuit in order to optimize its performance under different conditions. This RFID reader suitably provides optimal performance for both transponder reading and transponder writing operations, rather than being designed for optimal performance for only one operation or the other, or some fixed compromise between them.

Abstract: A vibrator device includes a semiconductor substrate, a base, a vibrating element, and a lid. The semiconductor substrate has a first surface and a second surface which is in a front-back relationship with the first surface. The base includes an integrated circuit disposed on a first surface or a second surface. The vibrating element is electrically coupled to the integrated circuit and is disposed on the first surface side. The lid is joined to the base at a joining portion of the base to accommodate the vibrating element. The integrated circuit includes a passive element, and the passive element is disposed such that at least a part of the passive element overlaps with the joining portion in a plan view from a direction orthogonal to the first surface.

Abstract: An integrated circuit includes a first coupling terminal and a second coupling terminal disposed along a first side, an oscillation circuit which is electrically coupled to a resonator element via the first coupling terminal and the second coupling terminal, a temperature sensor, a temperature compensation circuit configured to compensate a temperature characteristic of the resonator element based on an output signal of the temperature sensor, and an output circuit to which a signal output from the oscillation circuit is input, and which is configured to output an oscillation signal, wherein d1<d0 and d2<d0, in which an end-to-end distance between the temperature sensor and the output circuit is d0, an end-to-end distance between the first coupling terminal and the output circuit is d1, and an end-to-end distance between the second coupling terminal and the output circuit is d2.

Abstract: Example embodiments of systems and methods for data transmission between a contactless card, a client device, and one or more servers are provided. The memory of the contactless card may include one or more applets and a counter. The client device may be in data communication with the contactless card and one or more servers, and the one or more servers may include an expected counter value. The client device may be configured to read the counter from the contactless card and transmit it to the one or more servers. The one or more servers may compare the counter to the expected counter value for synchronization. The contactless card and the one or more servers may resynchronize the counter, via one or more processes, based on one or more reads of the one or more applets. The one or more servers may authenticate the contactless card based on the resynchronization.

Abstract: An ultra-low noise crystal oscillator uses two crystal unit; an oscillation element of an oscillation circuit section and a crystal filter of a subsequent filter section. A Butler circuit in which the capacitors (C1, C2) and the inductor (L) connected in series is connected in parallel to the oscillator circuit section. This is the crystal oscillator that simplifies the manufacturing process, improves the manufacturing quality, and has good floor noise characteristics.

Abstract: The circuit device includes a current generation circuit configured to generate a temperature compensation current based on a temperature detection voltage, and a current-voltage conversion circuit configured to perform current-voltage conversion on the temperature compensation current to output a temperature compensation voltage. The current-voltage conversion circuit includes an operational amplifier, and a feedback circuit. The operational amplifier includes a differential section having a current mirror circuit and differential pair transistors, an output section configured to output the temperature compensation voltage, and an RC low-pass filter configured to output a signal obtained by performing a low-pass filter process on an output signal of the differential section to an input node of the output section.

Abstract: A vibration element includes: a quartz crystal substrate having a first vibration part and a second vibration part; a pair of first excitation electrodes formed at two main surfaces of the quartz crystal substrate, at the first vibration part; and a pair of second excitation electrodes formed in such a way as to sandwich the second vibration part in a direction of thickness of the quartz crystal substrate, at the second vibration part. At least one second excitation electrode of the pair of second excitation electrodes is formed at an inclined surface inclined to at least one of the two main surfaces.

Abstract: An oscillator comprising an RC oscillator and a bandgap reference source, wherein the bandgap reference source provides a reference current for the RC oscillator, and a temperature coefficient of the reference current is adjustable. Since the oscillation frequency of the RC oscillator has less dependency on a power supply, a clock source having a relatively precise frequency thus can be obtained; and based on the RC oscillator, the bandgap reference source having a temperature compensation function is added, the reference current generated by the bandgap reference source with an adjustable temperature coefficient is used for temperature coefficient compensation to the inherent temperature coefficient of the oscillation frequency of the RC oscillator, thereby reducing the effect of the temperature on the oscillator, so that the output frequency of the oscillator does not change with the temperature as far as possible, which improves the oscillation frequency precision of the oscillator.

Abstract: An oscillator includes: a base substrate having a first electrode; a temperature control element mounted on the base substrate and having a first pad electrically coupled to the first electrode; a resonator element having a first major surface and a second major surface in front-back relation with the first major surface, and mounted on the temperature control element in such a way that the second major surface faces the temperature control element; and at least one first bonding wire coupling the first major surface and the first pad together.

Abstract: A smart method is provided for a low-current oscillatory circuitry. The circuitry comprises an oscillator and a microcontroller unit (MCU). The oscillator comprises a proportional-to-absolute-temperature circuit connecting to a low-voltage regulator. The low-voltage regulator connects to a PMOS diode array and a delay unit circuit. The PMOS diode array connects to the MCU. The delay unit circuit connects to the MCU and a voltage converter. The method includes a normal temperature compensation algorithm; a smart learning algorithm of extra-high temperature compensation; and an ultra-high temperature compensation algorithm. Thus, clock variations are compensated; output frequency is stable and not affected by voltage or temperature variations; and process variations are suppressed. When process variations appear, there are not be too many errors generated.

Abstract: A semiconductor device includes transistor cells in a semiconductor portion, wherein the transistor cells are electrically connected to a gate metallization, a source electrode and a drain electrode. In one example, the semiconductor device further includes a doped region in the semiconductor portion. The doped region is electrically connected to the source electrode. A resistance of the doped region has a negative temperature coefficient. An interlayer dielectric separates the gate metallization from the doped region. A drain structure in the semiconductor portion electrically connects the transistor cells with the drain electrode and forms a pn junction with the doped region.

Abstract: A circuit device includes a control voltage input terminal to which a control voltage is inputted, an A/D conversion circuit A/D-converting the control voltage to generate control voltage data and A/D-converting a temperature detection voltage from a temperature sensor to generate temperature detection data, a processing circuit generating temperature compensation data of an oscillation frequency based on the temperature detection data and performing addition processing of the temperature compensation data and the control voltage data to generate frequency control data of the oscillation frequency, and an oscillation signal generation circuit generating an oscillation signal of the oscillation frequency set by the frequency control data, using the frequency control data and a resonator.

Abstract: Example embodiments of systems and methods for data transmission between a contactless card, a client device, and one or more servers are provided. The memory of the contactless card may include one or more applets and a counter. The client device may be in data communication with the contactless card and one or more servers, and the one or more servers may include an expected counter value. The client device may be configured to read the counter from the contactless card and transmit it to the one or more servers. The one or more servers may compare the counter to the expected counter value for synchronization. The contactless card and the one or more servers may resynchronize the counter, via one or more processes, based on one or more reads of the one or more applets. The one or more servers may authenticate the contactless card based on the resynchronization.

Abstract: In a high resolution temperature sensor, first and second MEMS resonators generate respective first and second clock signals and a locked-loop reference clock generator generates a reference clock signal having a frequency that is phase-locked to at least one of the first and second clock signals. A frequency-ratio engine within the MEMS temperature sensor oversamples at least one of the first and second clock signals with the reference clock signal to generate a ratio of the frequencies of the first and second clock signals.

Abstract: Circuits and methods for current recycling in signal buffers for switched capacitor circuits are described. A signal buffer may be coupled to an impedance element, such as a resistor, configured to provide a desired reference voltage to the switched capacitor circuit. In some embodiments, a portion of the power absorbed by the impedance element may be recycled to power one or more additional circuit. Such additional circuit(s) may include active elements. In some embodiments, the switched capacitor circuit is part of an analog-to-digital converter. In some embodiments, the additional circuit(s) are also part of the analog-to-digital converter.

Abstract: An oscillator includes a control voltage generator that generates a control voltage between a first reference voltage and a second reference voltage with a digital signal, and a voltage controlled oscillation circuit that outputs a signal at a frequency in response to the control voltage. The control voltage generator includes a first D/A conversion circuit of resistor voltage-dividing type that generates a voltage between the first reference voltage and the second reference voltage.

Abstract: A thermal sensor comprises a converter circuit, a counting circuit, and a ratio calculator. The converter circuit is configured to convert a temperature-independent signal into a first frequency signal, and to convert a temperature-dependent signal into a second frequency signal. The counting circuit is configured to receive at least one of the first frequency signal and the second frequency signal, to count a predetermined number of pulses of the first frequency signal, and to count a number of pulses of the second frequency signal for a time period corresponding to the counting of the predetermined number of pulses of the first frequency signal. The ratio calculator is configured to calculate a ratio based on the predetermined number of pulses of the first frequency signal and the counted number of pulses of the second frequency signal.

Abstract: A wireless seismic data acquisition unit with a wireless receiver providing access to a common remote time reference shared by a plurality of wireless seismic data acquisition units in a seismic system. The receiver is capable of replicating local version of remote time epoch to which a seismic sensor analog-to-digital converter is synchronized. The receiver is capable of replicating local version of remote common time reference for the purpose of time stamping local node events. The receiver is capable of being placed in a low power, non-operational state over periods of time during which the seismic data acquisition unit continues to record seismic data, thus conserving unit battery power. The system implements a method to correct the local time clock based on intermittent access to the common remote time reference. The method corrects the local time clock via a voltage controlled oscillator to account for environmentally induced timing errors.

Abstract: A semiconductor circuit device includes an oscillation circuit, an output circuit that outputs a signal output from the oscillation circuit, a temperature sensing element, a characteristic adjustment circuit that adjusts characteristics of the oscillation circuit on the basis of a signal output from the temperature sensing element, a first wiring via which power is supplied to the output circuit, and a second wiring via which a reference voltage is supplied to the output circuit in which at least one of the first wiring and the second wiring overlaps the temperature sensing element in a plan view.

Abstract: A wireless seismic data acquisition unit with a wireless receiver providing access to a common remote time reference shared by a plurality of wireless seismic data acquisition units in a seismic system. The receiver is capable of replicating local version of remote time epoch to which a seismic sensor analog-to-digital converter is synchronized. The receiver is capable of replicating local version of remote common time reference for the purpose of time stamping local node events. The receiver is capable of being placed in a low power, non-operational state over periods of time during which the seismic data acquisition unit continues to record seismic data, thus conserving unit battery power. The system implements a method to correct the local time clock based on intermittent access to the common remote time reference. The method corrects the local time clock via a voltage controlled oscillator to account for environmentally induced timing errors.

Abstract: A method of adjusting a frequency of a resonation device including a resonator element and a heating element includes performing the frequency adjustment of the resonator element while heating the resonator element by the heating element.

Abstract: A system includes an oscillator referenced to a frequency extracted from periodic intensity modulations of incident light. The incident light can be intensity modulated based on the frequency of the AC voltage that powers artificial lighting. The system includes a light-sensitive element configured to generate an output signal indicative of an intensity of incident light and a controller. The controller can receive a first input signal based on the output signal from the light-sensitive element. In the presence of artificial lighting, the first input signal has a frequency based on a reference frequency at which an intensity of light incident on the light-sensitive element periodically varies. The controller can generate a control signal based in part on the reference frequency. The controller can provide the generated control signal to the adjustable oscillator to thereby adjust the oscillator frequency.

Abstract: According to one embodiment, a radio frequency (RF) transceiver includes a local oscillator generator (LOGEN) circuit configured to receive an adaptive supply voltage. The LOGEN circuit is coupled to a variable power supply for providing the adaptive supply voltage. A process monitor for the LOGEN circuit is in communication with the variable power supply through a power supply programming module. As a result, the adaptive supply voltage can be adjusted according to data supplied by the process monitor. A method for adaptively powering a LOGEN circuit comprises providing power to an RF device, monitoring a process corner of said LOGEN circuit, determining a supply voltage corresponding to the process corner, and adjusting the supply voltage to adaptively power the LOGEN circuit.

Abstract: An oscillation circuit includes a first variable capacitance part which includes a first variable capacitance element whose capacitance is controlled on the basis of a potential difference between a first control voltage and a first reference voltage, and is connected to the oscillation circuit, a second variable capacitance part which includes a second variable capacitance element whose capacitance is controlled on the basis of a potential difference between a first control voltage and a second reference voltage, and is connected to the oscillation circuit.

Abstract: A clock signal generation circuit includes a CR oscillator circuit having a capacitor, a resistor, and an amplifier circuit, and a voltage generation circuit adapted to generate a power supply voltage, and then supply the CR oscillator circuit 170 with the power supply voltage VDOS. An oscillation frequency of the CR oscillator circuit in a case in which a power supply voltage VDDL is a fixed voltage has a positive temperature characteristic. The voltage generation circuit generates the power supply voltage VDOS having a negative temperature characteristic based on a work function difference between transistors, and then supplies the power supply voltage VDOS as a power of the amplifier circuit of the CR oscillator circuit.

Abstract: A temperature control device includes a temperature detector, a difference operation unit, a controller, a saturation processing circuit unit, a rewritable storage unit, and a conversion unit. The difference operation unit operates a digital value corresponding to a difference value between a detected temperature value and a target temperature. The controller calculates a manipulated variable using the digital value operated by the difference operation unit. The saturation processing circuit unit includes a digital circuit to limit an output value of the controller to a pre-set upper limit value. The rewritable storage unit stores the upper limit value read from a storage area of the rewritable storage unit and input into the saturation processing circuit unit. The conversion unit converts the output value of the saturation processing circuit unit into an analog signal to output the converted value as a control command value to the heater.

Abstract: A constant-temperature piezoelectric oscillator includes: a piezoelectric vibrator; an oscillation circuit; a frequency voltage control circuit; a temperature control section; and an arithmetic circuit, wherein the temperature control section includes a temperature-sensitive element, a heating element, and a temperature control circuit, the frequency voltage control circuit includes a voltage-controlled capacitance circuit capable of varying the capacitance value in accordance with the voltage, and a compensation voltage generation circuit, and the arithmetic circuit makes the compensation voltage generation circuit generate a voltage for compensating a frequency deviation due to a temperature difference between zero temperature coefficient temperature Tp of the piezoelectric vibrator and setting temperature Tov of the temperature control section based on a frequency-temperature characteristic compensation amount approximate formula adapted to compensate the frequency deviation, and then applies the voltage t

Abstract: A method includes generation of a first current proportional to absolute temperature and formation of a second current representative of the temperature variation of the threshold voltages of the transistors of the inverter and limited to a fraction of the first current. This fraction is less than one. The inverter is supplied with a supply current equal to the first current minus the limited second current.

Abstract: A package structure of crystal oscillator with embedded thermistor is disclosed. The package structure comprises a ceramic substrate. A crystal oscillation device is mounted in the accommodation space of the ceramic substrate. A cover is used to seal the accommodation space. At least one thermistor is embedded in the ceramic substrate. A patterned metal interconnection in the ceramic substrate is electrically connected with the crystal oscillation device and the thermistor, respectively. The present invention describes as follows: the thermistor is directly embedded in the ceramic substrate to avoid the short-circuit problem caused by electroplating a thermistor exposed and shorten a distance between the thermistor and the crystal oscillation device. Thus, the thermistor can more precisely sense the operating temperature of the crystal oscillation device to timely compensate frequency drift caused by changing the temperature of the crystal oscillation device.

Abstract: An oscillator circuit includes a resistor configured to control an oscillating frequency. The resistor includes a positive temperature coefficient resistor and a negative temperature coefficient resistor. The positive temperature coefficient resistor has a resistance, which increases in response to increase in temperature. The negative temperature coefficient resistor has a resistance, which decreases in response to increase in temperature.

Abstract: The temperature compensated timing signal generator comprises a crystal oscillator that generates a reference time signal, and a divider circuit that receives the reference time signal as input and outputs a coarse time unit signal, the coarse time unit signal having an actual frequency deviating from a desired frequency as a function of temperature of the crystal oscillator. The signal generator also includes a high frequency oscillator configured to generate an interpolation signal having a frequency greater than the frequency of the crystal oscillator. A finite state machine computes a deviation compensating signal as a function of temperature, the signal comprises an integer part representative of an integer number of pulses to be inhibited or injected in the divider circuit and a fractional part representative of how much the output of a new time unit signal pulse should further be delayed to compensate for any remaining deviation.

Abstract: The temperature compensated timing signal generator comprises a crystal oscillator that generates a reference time signal, and a divider circuit that receives the reference time signal as input and outputs a coarse time unit signal, the coarse time unit signal having an actual frequency deviating from a desired frequency as a function of temperature of the crystal oscillator. The signal generator also includes a high frequency oscillator that generates an interpolation signal having a frequency greater than the frequency of the crystal oscillator. A finite state machine computes a deviation compensating signal as a function of the temperature signal, the signal comprises an integer part representative of an integer number of pulses to be inhibited or injected in the divider circuit and a fractional part representative of how much the output of a new time unit signal pulse should further be delayed to compensate for any remaining deviation.

Abstract: A crystal resonator comprises a first vibrating region provided on a crystal wafer, a second vibrating region provided on the crystal wafer, the second vibrating region having a different thickness and positive/negative orientation of the X-axis from those of the first vibrating region, and excitation electrodes which are provided respectively on the first vibrating region and the second vibrating region for causing the vibrating regions to vibrate independently. Frequencies that change by different amounts from each other relative to a temperature change can be retrieved from one vibrating region and the other vibrating region. Thus, based on an oscillating frequency of the vibrating region in which a clear frequency change occurs relative to the temperature, the oscillating frequency of the other vibrating region can be controlled. Thereby, increases in the complexity of the crystal oscillator can be suppressed.

Abstract: An oscillator which oscillates electromagnetic waves includes a negative differential resistance element, a resonator configured to prescribe oscillation frequencies of the electromagnetic waves, a voltage modulation unit configured to modulate the negative differential resistance element, a stabilizing circuit configured to suppress parasitic oscillation, and a bias circuit, including a power supply and a line, used to control an operating point voltage of the negative differential resistance element. The voltage modulation unit is connected to the bias circuit through the stabilizing circuit.

Abstract: A device comprising, a mirror which is configured to oscillate in response to an oscillation signal, wherein the device is configured such that oscillation of the mirror will induce a signal; and a circuit in operable cooperation with the mirror such that an induced signal can be measured by the circuit and wherein the circuit is configured to provide an oscillation signal proportional to the measured induced signal; wherein the device is configured such that the mirror can receive the oscillation signal so that the oscillation signal is filtered due to oscillation limitations of mirror, to provide a filtered signal.

Abstract: The LC tank of a VCO includes a main varactor circuit and temperature compensation varactor circuit coupled in parallel with the main varactor circuit. The main varactor is used for fine tuning. The temperature compensation varactor circuit has a capacitance-voltage characteristic that differs from a capacitance-voltage characteristic of the main varactor circuit such that the effects of common mode noise across the two varactor circuits are minimized. The LC tank also has a plurality of switchable capacitor circuits provided for coarse tuning. To prevent breakdown of the main thin oxide switch in each of the switchable capacitor circuits, each switchable capacitor circuit has a capacitive voltage divider circuit that reduces the voltage across the main thin oxide switch when the main switch is off.

Abstract: A crystal controlled oscillator of the present disclosure includes: an oscillator circuit for oscillator output, a first oscillator circuit, a second oscillator circuit, a heating unit, a pulse generator, a frequency difference detector, an addition unit, a circuit unit, a frequency measuring unit, a determination unit, and a signal selector. The signal selector is configured to: select a control signal where electric power supplied to the heating unit is smaller than supplied electric power in the detection range in a case where a frequency in a set period at the train of pulses is out of the detection range at the high temperature side; select a control signal where electric power supplied to the heating unit becomes a preset value in a case where a frequency in the set period at the train of pulses is out of the detection range at the low temperature side.

Abstract: A temperature controlled oscillator includes an oscillation unit and a filter unit. The oscillation unit is configured to generate at least one reference voltage based on a supply voltage and a ground voltage, and to generate an oscillation signal having a period varying according to a temperature, the oscillation unit configured to generate the oscillation signal based on a filter voltage and the at least one reference voltage. The filter unit is configured to generate the filter voltage based on the oscillation signal.

Abstract: A piezoelectric device includes an insulating substrate, a piezoelectric vibration device that is mounted on a device mounting pad, a metal lid member that seals the piezoelectric vibration device in an airtight manner, an external pad that is arranged outside the insulating substrate, an oscillation circuit, a temperature compensation circuit, and a temperature sensor. The lid member and the temperature sensor or the lid member and the IC component are connected to each other so as to be heat-transferable, and a heat transfer member having thermal conductivity higher than that of the material of the insulating substrate is additionally included.

Abstract: A piezoelectric device includes an insulating substrate, a piezoelectric vibration device that is mounted on a device mounting pad, a metal lid member that seals the piezoelectric vibration device in an airtight manner, an external pad that is arranged outside the insulating substrate, an oscillation circuit, a temperature compensation circuit, and a temperature sensor. The lid member and the temperature sensor or the lid member and the IC component are connected to each other so as to be heat-transferable, and a heat transfer member having thermal conductivity higher than that of the material of the insulating substrate is additionally included.

Abstract: A temperature invariant digitally controlled oscillator is disclosed. The digitally controlled oscillator is configured to generate an output clock with stable frequency. The temperature invariant digitally controlled oscillator comprises a digitally controlled oscillator, a temperature sensor, a temperature decision logic circuit, and a temperature conditioner. The digitally controlled signal is provided to adjust the oscillation frequency of the digitally controlled oscillator by changing its capacitances. The stabilization of the silicon temperature is achieved with the temperature sensor, the temperature decision logic circuit, and the temperature conditioner.

Abstract: An electronic device may include a voltage controlled oscillator (VCO) and a temperature sensor. The electronic device may also include a controller configured to cooperate with the VCO and the temperature sensor to determine both a temperature and a frequency error of the VCO for each of a plurality of most recent samples. Each of the most recent samples may have a given age associated therewith. The controller may also be configured to align the temperature, the frequency error, and the given age for each of most recent samples in a three-dimensional (3D) coordinate system having respective temperature, frequency error and age axes. The controller may also be configured to estimate a predicted frequency error of the VCO based upon the aligned temperature, frequency error, and given age of the most recent samples.

Abstract: An apparatus and a method for compensating for a mismatch in temperature coefficients of two oscillator frequencies to match a desired frequency ratio between the two oscillator frequencies over a temperature range. In one embodiment of a temperature sensor, first and second oscillators of different temperature characteristics are coupled to a differential frequency discriminator (DFD) circuit. The DFD circuit compensates for the different characteristics in order to match a frequency difference between the first and second frequencies over a temperature range.

Abstract: A semiconductor device. The semiconductor device includes: an oscillator; a semiconductor chip that includes an oscillation circuit connected to the oscillator, a timer circuit that generates a timing signal of a frequency according to a oscillation frequency of the oscillation circuit, and a frequency correction section that corrects a frequency of the timing signal based on temperature data; and a discrete device that includes at least one of a temperature sensing device that detects a peripheral temperature, that supplies the detected temperature as temperature data to the frequency correction section, and that is provided as a separate body to the semiconductor chip, or a capacitor that is electrically connected to both the oscillator and the oscillation circuit and that is provided as a separate body to the semiconductor chip, wherein the oscillator, the semiconductor chip and the discrete device are contained within a single package.

Abstract: One aspect of the present invention includes a reference current generator circuit. The circuit includes a bias circuit configured to generate a reference current along a first current path and a second current along a second current path. The reference current and the second current can be proportional. The circuit also includes a first pair of transistors connected in series and configured to conduct the reference current in the first current path. The circuit further includes a second pair of transistors connected in series and configured to conduct the second current in the second current path. The second pair of transistors can be coupled to the first pair of transistors to provide a collective resistance value of the second pair of transistors that is proportional to temperature.

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: A function generator circuit includes a temperature detecting circuit outputting a detection voltage corresponding to an ambient temperature and having a linear temperature characteristic. Zeroth-order, first-order and second-order component generating circuits generate a zeroth-order component, a first-order component and a second-order component, respectively, of the control signal. A third-order component generating circuit generates a third-order component of the control signal based on the detection voltage. An adder-subtractor generates the control signal by obtaining a sum of the zeroth-order component, the first-order component, and the third-order component and adding or subtracting the second-order component to or from the sum. The second-order component generating circuit corrects a temperature at an inflection point of the control signal.

Abstract: An oven controlled crystal oscillator includes a crystal unit, a temperature control circuit, and a circuit board. The temperature control circuit is configured to control a temperature of the crystal unit. The crystal unit includes a flange that projects outward to an entire outer periphery in one end. The circuit board includes a depressed portion in which the flange is partially inserted. The temperature control circuit includes a power transistor, a thermistor as a temperature sensor, and a metal pattern. The power transistor becomes a heat source. The metal pattern commonly connects a ground terminal of the crystal unit, a collector of the power transistor, and a ground terminal of the thermistor. The crystal unit is positioned in a state where the flange is partially inserted in the depressed portion. The crystal unit is connected to the metal pattern.