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: To determine the level of frequency drift of a crystal oscillator as a result of a change in the its temperature, the temperature of the crystal oscillator is sensed and used together with previously stored data that includes a multitude of drift values of the frequency of the crystal oscillator each associated with a temperature of the crystal oscillator. Optionally, upon initialization of a GPS receiver in which the crystal oscillator is disposed, an initial temperature of the crystal oscillator is measured and a PLL is set to an initial frequency in association with the initial temperature. When acquisition fails in a region, the ppm region is changed. The temperature of the crystal oscillator is periodically measured and compared with the initial temperature, and the acquisition process is reset if there is a significant change in temperature. The GPS processor enters the tracking phase when acquisition is successful.

Abstract: One embodiment of communication system comprises a crystal oscillator configured to output a reference clock; cellular radio frequency (RF) and baseband phase locked loops configured to receive the reference clock within a cellular module and compensate for calculated frequency errors between a received cellular downlink signal and a cellular local oscillator signal during operation of the cellular module; global positioning system (GPS) frequency compensation circuitry configured to receive the reference clock within a GPS module and compensate for calculated frequency errors during operation of the GPS module; and a temperature sensing circuit which includes a plurality of sensing resistors and is configured to output a signal corresponding to a temperature of a reference crystal which is translated to a frequency deviation, wherein the (GPS) frequency compensation circuitry is configured to offset the frequency deviation and output a temperate compensated signal to meet GPS clock frequency requirements.

Abstract: An oscillator circuit includes a signal generator having a compensation frequency output node that provides a compensation frequency signal at the compensation frequency output node. A pulse generator having a pulsed signal output node and a pulse generator input node is coupled to the compensation frequency output node and converts the compensation frequency signal into a series of compensation binary pulses having a constant pulse duration regardless of variations in the duty cycle of the compensation binary pulses. An oscillator module having at least two capacitors, an oscillator output node and a pulsed signal input node is coupled to the pulsed signal output node, and provides an output signal that is at a frequency dependent on charging rates of the capacitors. Drift variations in the capacitors are offset by variations in a duty cycle of the compensation binary pulses supplied in order to maintain constant charging rates of the capacitors.

Abstract: Provided is a temperature compensated oscillator includes an oscillation circuit for oscillating an oscillator. In the oscillator, when an oscillation frequency is changed by a second control signal after being controlled by a first control signal, variation in the oscillation frequency due to a second control signal is set to a fixed amount. The oscillation frequency of the oscillator is controlled on the basis of both the first control signal and the second control signal, but an oscillation amplitude adjusting section is also added, the oscillation amplitude adjusting section allowing the oscillation amplitude of the oscillator to be changed by the second control signal. The oscillator thus allows a fixed amount of oscillation frequency control over a wide range (full range) of oscillation frequency control due to the first control signal.

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: In one embodiment, there is a method that can include utilizing a ring oscillator module to determine a process corner of an integrated circuit as fabricated that includes the ring oscillator module. The impedance of an output driver of the integrated circuit can be altered based on the process corner of the integrated circuit as fabricated.

Abstract: An adaptive hybrid system is coupled to a loop for adjusting trans-hybrid loss. The system comprises a fixed portion comprising a first receiver transfer function block and a first hybrid transfer function block. The fixed portion is configured to receive a far-end signal and mitigate frequency dependent attenuation experienced by the far-end signal. The system also comprises a variable portion comprising a second receiver transfer function block and a second hybrid transfer function block configured to subtract a transmit echo from the received far-end signal.

Abstract: A crystal oscillator is provided, which varies a frequency drift compensation according to a power consumption and compensates a frequency drift characteristic caused by heat. An adder is used to add a temperature compensation control voltage from a temperature compensation circuit, an oscillating frequency control voltage from an AFC circuit, and a frequency drift compensation voltage corresponding to the power consumption from a frequency drift compensation circuit. A voltage added by the adder is outputted to voltage-variable capacitor elements and, which respectively are connected to an input side and an output side of an inverter IC that is connected in parallel to a crystal oscillating unit.

Abstract: An oscillating device includes a temperature compensated oscillator that compensates a frequency temperature characteristic in a temperature compensation range including apart of a first temperature range, and a temperature control circuit that includes a heater and controls a temperature of a quartz crystal resonator of the temperature compensated oscillator into a second temperature range included in the temperature compensation range. Further, the temperature compensation range of the temperature compensated oscillator may include a part of the first temperature range in which compensation can be performed by first-order approximation.

Abstract: An atomic oscillator includes: a gas cell in which a gaseous metal atom is sealed; first and second heaters heating the gas cell; an exciting light source exciting the metal atom; a light detector detecting the exciting light; a substrate including a temperature controlling circuit for the heaters; a first wiring coupling the first heater and the substrate; a second wiring coupling the second heater and the substrate; and a third wiring coupling the first heater and the second heater. In the atomic oscillator, the gas cell includes a cylinder and windows sealing both ends of the cylinder and constituting an incident surface and an emitting surface on an optical path of the exciting light. The first and second heaters are respectively formed on the windows at an incident surface side and an emitting surface side and are made of transparent heating materials.

Abstract: A synthesizer includes a synthesizer unit for generating a local oscillation signal based on a reference oscillation signal output from a reference oscillation unit including a MEMS resonator, a frequency fluctuation detector for detecting a frequency fluctuation of the MEMS resonator, and a frequency adjuster for adjusting a frequency of the local oscillation signal based on the frequency fluctuation detected by the frequency fluctuation detector. This synthesizer can output a signal with a stable frequency, even when an MEMS resonator demonstrating a large fluctuation in an oscillation frequency to temperatures is used.

Abstract: A semiconductor integrated circuit device includes a DCO and a storing unit that stores a temperature coefficient of an oscillation frequency and an absolute value of the oscillation frequency, which should be set in the DCO, corresponding to potential obtained from a voltage source that changes with a monotonic characteristic with respect to temperature.

Abstract: An oscillation device capable of highly accurate temperature compensation of an output frequency is provided. The oscillation device includes: first and second oscillator circuits oscillating first and second quartz-crystal resonators with overtones respectively; a frequency difference detecting part finding a value corresponding to a difference value between values corresponding to differences between f1 and f1r and between f2 and f2r, where f1 and f2 are oscillation frequencies of the first and second oscillator circuits, and f1r and f2r are oscillation frequencies of the first and second oscillator circuits at a reference temperature; and a correction value obtaining part which, based on the value corresponding to the difference value and a relation between the value corresponding to the difference value and a frequency correction value of the oscillation frequency f1, obtains the frequency correction value of f1, wherein the output frequency is corrected based on the found frequency correction value.

Abstract: To perform, in an oscillation device compensating an output frequency based on a detection result of ambient temperature, temperature compensation of the output frequency with high accuracy. First and second quartz-crystal oscillators are structured by using a common quartz-crystal piece, and when oscillation outputs of first and second oscillation circuits respectively connected to these quartz-crystal oscillators are set to f1, f2, and oscillation frequencies of the first and the second oscillation circuits at a reference temperature are set to f1r, f2r, respectively, a frequency difference being a difference between a value corresponding to a difference between f1 and f1r and a value corresponding to a difference between f2 and f2r is treated as a temperature at that time. Further, based on the frequency difference, a frequency compensation value is determined through polynomial approximation.

Abstract: A crystal oscillator with improved tolerance to radiation such as X-rays includes: a container body; a quartz crystal blank accommodated in a first recess formed on one main surface of the container body and hermetically encapsulated in the first recess by a metal cover; and an IC chip that integrates electronic circuits including at least an oscillator circuit using the crystal blank and is accommodated in the second recess formed on the other main surface of the container body. The IC chip is fixed to the bottom surface of the second recess by flip-chip bonding such that a circuit formation plane of the IC chip is opposed to the bottom surface of the second recess. A radiation protective film is formed on the main surface other than the circuit formation plane of the IC chip.

Abstract: A semiconductor device includes an oscillator that oscillates at a specific frequency, a semiconductor integrated circuit that integrates a temperature sensor that detects a peripheral temperature, and a controller that is electrically connected to the oscillator and that corrects temperature dependent error in the oscillation frequency of the oscillator based on the temperature detected by the temperature sensor and a sealing member that integrally seals the oscillator and the semiconductor integrated circuit.

Abstract: According to one embodiment, an oscillator circuit includes a first comparator circuit, a second comparator circuit, a first voltage control circuit, a second voltage control circuit, a clock generation circuit. The first comparator circuit is configured to compare a first voltage with a first threshold voltage to generate a first comparison result. The second comparator circuit is configured to compare a second voltage with a second threshold voltage to generate a second comparison result. The first voltage control circuit is configured to decrease the first voltage by a first voltage value in synchronization with timing when the first comparison result changes. The second voltage control circuit is configured to decrease the second voltage by a second voltage value in synchronization with timing when the second comparison result changes.

Abstract: A method and apparatus for compensating an oscillator in a location-enabled wireless device is described. In an example, a mobile device includes a wireless receiver for receiving wireless signals and a GPS receiver for receiving GPS signals. The mobile device also includes an oscillator having an associated temperature model. A frequency error is derived from a wireless signal. The temperature model is adjusted in response to the frequency error and a temperature proximate the oscillator. Frequency error of the oscillator is compensated using the adjusted temperature model. In another example, a frequency error is derived using a second oscillator within the wireless receiver.

Abstract: A temperature-controlled crystal oscillating unit and oscillator are provided, which can stabilize an output frequency thereof, have firmness against shock of falling etc., and are suitable for miniaturization and mass production. A crystal blank for the temperature-controlled crystal oscillating unit is formed by an inner region which is an oscillating plate; an outer region which surrounds the periphery of the inner region; and a connection portion which connects the inner region with the outer region. Electrodes are formed on two surfaces of the inner region, and a heater and a temperature sensor are disposed to surround the periphery of the electrode on one surface of the inner region where the electrode is formed thereon. The electrodes, the heater and the temperature sensor are respectively connected with terminals on the outer region by leads. A contact area between the temperature sensor and a crystal is increased.

Abstract: A buffer is provided. The buffer includes a buffering stage that receives an enable signal and an input signal and that provides an output signal and a bandgap stage that is coupled to the buffering stage and that is activated and deactivated by the enable signal. In particular, the buffering stage includes a buffering substage that includes a buffering transistor that is coupled to the input stage, wherein the buffering transistor is formed on a substrate, and wherein the buffering transistor has a channel with a doping concentration that is approximately the same as the substrate.

Abstract: Provided is an oscillation device capable of obtaining a stable oscillation frequency by compensating for a change in oscillation frequency caused with an elapse of operating time of a quartz-crystal oscillator. A difference value ?F between a frequency difference between first and second quartz-crystal oscillators after a predetermined period of time has elapsed from a reference time and a frequency difference between the first and second quartz-crystal oscillators at the reference time is determined.

Abstract: A temperature compensation circuit may include a temperature coefficient generator configured to generate a first signal and a second signal, wherein the first signal is proportional-to-absolute-temperature (ptat) and the second signal in negatively-proportional-to-absolute temperature (ntat), a first programmable element configured to multiply at a first programmable ratio an amplitude of a third signal having a negative temperature coefficient from a first temperature to a second temperature, and a second programmable element configured to multiply at a second programmable ratio an amplitude of a fourth signal having a positive temperature coefficient from the second temperature to a third temperature.

Abstract: A method and apparatus for compensating for temperature variation in a phase locked loop (PLL) includes receiving an error signal by a controller in which the error signal representative of an instantaneous frequency difference between a reference frequency signal and an output frequency signal of a voltage controlled oscillator of the PLL, and determining when a voltage of the error signal is outside of a predetermined voltage range. When the voltage is outside the predetermined voltage range, the method includes generating a new digital compensation signal based upon a previous digital compensation signal, and converting the new digital compensation signal to be an analog compensation signal. The method further includes filtering the analog compensation signal by a filter to produce a filtered analog compensation signal, and adjusting the output frequency of the voltage controlled oscillator in accordance with the filtered analog compensation signal.

Abstract: An oscillation circuit including a reference voltage generation circuit that adds a proportional-to-absolute-temperature (PTAT) output, which increases in proportion to an absolute temperature, to a complementary-to-absolute-temperature (CTAT) output, which decreases in proportion to an absolute temperature, to generate and output a reference voltage. The oscillation circuit generates an oscillation signal having a desired and fixed frequency.

Abstract: A device includes an RC oscillator circuit and incorporates various features that individually and in combination can help improve the stability or accuracy of the oscillator output frequency. The oscillator circuit is operable to provide a tunable output frequency and includes a bias circuit switchable between first and second modes of operation. One of the modes has less drift in oscillator bias current relative to the other mode. The device also includes drift compensation circuitry that is operable to compensate for drift in the oscillator output frequency in a closed-loop mode of operation based on a comparison of the oscillator output frequency with a reference frequency. The device further includes a processor operable to compensate for temperature-based drift in the oscillator frequency in an open-loop mode of operation based on a measured temperature value in the vicinity of the oscillator circuit.

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 vibration device includes: a first vibrator having a 3rd-order function temperature characteristic in which a 3rd-order temperature coefficient is ??1, where ?1>0; and a second vibrator which is connected to the first vibrator, and has a 3rd-order function temperature characteristic in which a 3rd-order temperature coefficient is ?2, where ?2>0, wherein a difference between inflection points of the first and second vibrators is equal to or lower than 19° C., and a relationship of 0<|?1|?|2.4?2| is satisfied.

Abstract: An oscillation circuit includes a threshold voltage extraction module, a positive temperature coefficient voltage generation module, an addition module, a common-source amplifier module, a charge and discharge module, and a clock output terminal. The common-source amplifier module includes a first field effect transistor (FET) and a second FET. The addition module includes a first operational amplifier, a second operational amplifier, a third FET, a fourth FET, a fifth FET, a sixth FET, a first resistor, a second resistor, and a third resistor. The charge and discharge module includes a seventh FET, an eighth FET, a charge and discharge FET, a first switch, a second switch, a first comparator, a second comparator, a first nor gate and a second nor gate. An oscillation system is further provided. The oscillation circuit and the oscillation system of the present invention have simple structures and are easy to implement.

Abstract: A precise, low-consumption low-frequency oscillator includes a low-consumption low-frequency oscillator, operating at a frequency FA, a temperature-compensated oscillator B used as frequency standard, operating at a frequency FB, and a circuit for supplying a stable frequency Fcorr.

Abstract: A technique to use an auxiliary varactor coupled to a tuning varactor, in which a temperature compensated bias signal adjusts a bias on the auxiliary varactor to maintain a voltage controlled oscillator (VCO) from drifting in frequency as operating temperature for the VCO changes.

Abstract: A ring oscillator circuit for measurement of negative bias temperature instability effect and/or positive bias temperature instability effect includes a ring oscillator having first and second rails, and an odd number (at least 3) of repeating circuit structures. Each of the repeating circuit structures in turn includes an input terminal and an output terminal; a first p-type transistor having a gate, a first drain-source terminal coupled to the first rail, and a second drain source terminal selectively coupled to the output terminal; a first n-type transistor having a gate, a first drain-source terminal coupled to the second rail, and a second drain source terminal selectively coupled to the output terminal; and repeating-circuit-structure control circuitry. The ring oscillator circuit also includes a voltage supply and control block.

Abstract: Apparatus and methods are provided for oscillators having adjustable gain. An exemplary oscillator module comprises a first node for a first voltage, a control node for a control signal, and oscillator circuitry coupled to the first node and the control node. The oscillator circuitry generates an output signal with a first oscillation frequency based on the first voltage, and in response to the control signal being asserted, the oscillator circuitry generates the output signal with a second oscillation frequency based on the first voltage. The second oscillation frequency is greater than the first oscillation frequency.

Abstract: Systems and methods for calibrating real time clock are provided. A representative receiver includes a GPS device comprising a real time clock (RTC) circuitry that generates RTC clock signals and a temperature compensated crystal oscillator (TCXO) that generates TCXO clock signals. A ratio counter circuitry receives both the RTC clock signals and the TCXO clock signals and determines a frequency ratio by comparing the RTC clock signals and the TCXO clock signals. A computing device receives the frequency ratio and estimates a current RTC frequency based on the received frequency ratio. The computing device is configured to calibrate an estimated RTC time being maintained at the RTC circuitry based on an estimated RTC frequency from a prior estimation, the current RTC frequency and an elapsed time of the RTC circuitry.

Abstract: An oven controlled crystal oscillator includes a thermostatic bath, an inner circuit board, an outer circuit board, a heating element, and a temperature sensor. The inner circuit board comprising a crystal oscillation circuit is positioned inside the thermostatic bath and electrically connected with the outer circuit board via a pin. The outer circuit board has a temperature control circuit and a power supply circuit. The heating element and the temperature sensor electrically connect with the outer circuit board. A through slot is formed through the outer circuit board, and the thermostatic bath is inserted into the through slot. By inserting the thermostatic bath into the through slot of the outer circuit board, the height and the weight of the oven controlled crystal oscillator are reduced, the electric connection performance is enhanced, and thus the stability of the output frequency of the oven controlled crystal oscillator is improved.

Abstract: An oscillating apparatus includes: a transfer gate including a P-channel transistor and a N-channel transistor; a first inverter for inverting an output signal of the transfer gate and outputting the inverted output signal of the transfer gate; a second inverter for inverting the output signal of the first inverter and outputting the inverted output signal of the first inverter; a third inverter for inverting the output signal of the first inverter and outputting the inverted output signal of the first inverter; a fourth inverter for inverting the output signal of the third inverter and outputting the inverted output signal of the third inverter to an input-terminal of the transfer gate; a first capacitor connected between an output-terminal of the transfer gate and an output-terminal of the second inverter; and a second capacitor connected between the output-terminal of the transfer gate and a reference potential node.

Abstract: In embodiments of the present disclosure, a method may include determining an ambient temperature of an oscillator. The method may also include estimating an approximate frequency of operation of the oscillator. The method may additional include determining a process-based compensation to be applied to a resonator of the oscillator based on the approximate frequency. The method may further include setting a capacitance of a variable capacitor coupled to the resonator in order to compensate for temperature-dependent and process-dependent frequency variation of the oscillator based on the ambient temperature and the process-based compensation.

Abstract: In described embodiments, a wide toning-range (WTR) inductive-capacitive (LC) phase locked loop (PLL) provides for a large range of differing oscillation frequencies with a set of individual LC voltage controlled oscillator (VCO) paths. The output of each individual wide range LCVCO path is provided to a multiplexor (MUX), whose output is selected based on a control signal from, for example, a device controller. Each of the set of individual wide range LCVCO paths includes a switch that couples the LCVCO to a loop filter of a voltage tuning module, wherein each switch also receives the control signal to disable or enable the LCVCO path when providing the output signal from the MUX. Each switch is configured so as to minimize leakage current drawn by the LCVCO when disabled, and to reduce or eliminate effects of input capacitance of each dormant LCVCO to the loop dynamics of the PLL.

Abstract: Disclosed is an oscillator that relies on redundancy of similar resonators integrated on chip in order to fulfill the requirement of one single quartz resonator. The immediate benefit of that approach compared to quartz technology is the monolithic integration of the reference signal function, implying smaller devices as well as cost and power savings.

Abstract: An oscillation circuit includes: an oscillator that includes a vibrator and outputs an oscillation signal; an F/V converter that converts the oscillation signal into a voltage corresponding to a frequency of the oscillation signal; and a memory circuit that stores frequency correcting information for correcting the frequency of the oscillation signal.

Abstract: Methods and apparatus for temperature control of devices and mechanical resonating structures are described. A mechanical resonating structure may include a heating element and a temperature sensor. The temperature sensor may sense the temperature of the mechanical resonating structure, and the heating element may be adjusted to provide a desired level of heating. Optionally, additional heating elements and/or temperature sensors may be included.

Abstract: A clock generator is provided, capable of automatically adjusting an output clock when process, voltage, or temperature variation occurs. The clock generator includes a current generator, for generating a first current and a second current according to a bias signal, an oscillator, coupled to the current generator, for generating a clock signal according to the first current, a frequency detector, coupled to the oscillator, for generating a control signal according to the clock signal and a reference signal, and a bias voltage adjuster, coupled to the current generator and the frequency detector, for adjusting the bias signal according to the control signal. When the signal frequency of the clock signal changes, the bias signal corresponds to the bias voltage adjuster, to adjust the first current and the second current.

Abstract: A resonator according to the embodiment includes: a substrate; a flat layered body which is formed above the substrate and is formed with at least a lower electrode, a piezoelectric film and an upper electrode; an anchor portion which fixes the layered body above the substrate; a cut-out portion inside the layered body; a tuning fork vibrator which is formed in the cut-out portion, has both ends supported by the layered body and is formed with at least a lower electrode, a piezoelectric film and an upper electrode; and an envelope which envelopes the layered body and the tuning fork vibrator in a noncontact fashion, and prevents an external force from being applied to the layered body and the tuning fork vibrator.

Abstract: The present invention relates to an oven controlled crystal oscillator that can obtain stable oscillation frequency by reducing a temperature change in an oscillation element. The oven controlled crystal oscillator comprises; a heat-conducting plate mounted on one surface of a circuit board, a crystal resonator mounted on a surface of the heat-conducting plate opposite to the surface of the circuit board, an oscillation element constituting an oscillation circuit together with the crystal resonator, and a thermistor that detects temperature of the crystal resonator, a heating resistance which heats the crystal resonator, and a temperature control element including at least a power transistor, to constitute a temperature control circuit together with the thermistor and the heating resistance.

Abstract: An orthogonally referenced integrated ensemble for navigation and timing includes a dual-polyhedral oscillator array, including an outer sensing array of oscillators and an inner clock array of oscillators situated inside the outer sensing array. The outer sensing array includes a first pair of sensing oscillators situated along a first axis of the outer sensing array, a second pair of sensing oscillators situated along a second axis of the outer sensing array, and a third pair of sensing oscillators situated along a third axis of the outer sensing array. The inner clock array of oscillators includes a first pair of clock oscillators situated along a first axis of the inner clock array, a second pair of clock oscillators situated along a second axis of the inner clock array, and a third pair of clock oscillators situated along a third axis of the inner clock array.

Abstract: A method of manufacturing a quartz crystal unit comprises disposing a metal film on opposite surfaces of a quartz crystal wafer and then etching the wafer to form a two-line tuning fork resonator vibratable in a flexural mode of an inverse phase. A groove is formed in the opposite main surfaces of both tines, and the length of each groove is determined relative to the length of the resonator so that the series resistance of the fundamental mode of vibration of the resonator is less than the series resistance of the second overtone mode of vibration thereof. The resonator is then mounted in case after which the resonant frequency of the resonator is adjusted.

Abstract: To determine the level of frequency drift of a crystal oscillator as a result of a change in the its temperature, the temperature of the crystal oscillator is sensed and used together with previously stored data that includes a multitude of drift values of the frequency of the crystal oscillator each associated with a temperature of the crystal oscillator. Optionally, upon initialization of a GPS receiver in which the crystal oscillator is disposed, an initial temperature of the crystal oscillator is measured and a PLL is set to an initial frequency in association with the initial temperature. When acquisition fails in a region, the ppm region is changed. The temperature of the crystal oscillator is periodically measured and compared with the initial temperature, and the acquisition process is reset if there is a significant change in temperature. The GPS processor enters the tracking phase when acquisition is successful.

Abstract: An integrated circuit frequency generator is disclosed. In some embodiments, the frequency generator comprises an electronic oscillator configured to generate an oscillator frequency, calibration circuitry configured to periodically calibrate the electronic oscillator with respect to a reference frequency at a first calibration frequency when at a steady state temperature and at a second calibration frequency when at a transient temperature, and circuitry configured to generate an output frequency from the oscillator frequency.

Abstract: A compensating DFLL (CDFLL) is disclosed that utilizes temperature readings at regular intervals in combination with production characterization data of a reference oscillator to compensate for frequency drift and nominal frequency error. In some implementations, the CDFLL selects a calibration value that is not optimal for frequency accuracy to minimize accumulated frequency error over time. More particularly, during a calibration run, mismatch between an ideal frequency and an actual frequency is measured, and the measurement is used as a starting point for a next calibration run, such that the accumulated frequency error is averaged almost to zero over time.

Abstract: An inventive temperature-compensated crystal oscillator has a construction such that a crystal oscillator element (5) is accommodated in a container (1) and an IC element (7) for controlling an oscillation output on the basis of the oscillation of the crystal oscillator element (5) is mounted on a lower surface of the container (1). A plurality of electrode pads (10) at least including plural crystal electrode pads connected to the crystal oscillator element (5), plural writing control electrode pads, and an oscillation output electrode pad, a ground electrode pad, a power source voltage electrode pad and an oscillation control electrode pad connected to surface mounting external terminals are arranged in a matrix configuration of m rows×n columns (wherein m and n are natural numbers not smaller than 2) in an IC element mounting area. The IC element (7) is electrically connected to the electrode pads (10).