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.

An integrated circuit device includes a first temperature sensor, a second temperature sensor, an A/D conversion circuit that performs A/D conversion on first and second temperature detection voltages from the first and second temperature sensors and outputs first and second temperature detection data, a digital signal processing circuit that generates frequency control data by performing a temperature compensation process by a neural network calculation process based on the first and second temperature detection data, and an oscillation signal generation circuit that generates an oscillation signal of a frequency set by the frequency control data using a resonator.

Providing an OCXO having a highly stabilized output frequency. In an oscillator, which is an OCXO, crystal resonators, oscillator circuits, a temperature detector, and a heater circuit are disposed inside a first container, which is supported in a state of floating inside a second container, while a voltage stabilizer circuit for stabilizing a supply voltage supplied to the heater circuit is disposed apart from the first container inside the second container. Therefore, the supply voltage supplied to the heater circuit is stabilized. The voltage stabilizer circuit is less likely to be affected by heat generation of the heater circuit, thus obtaining a stable oscillation frequency output regardless of the environmental temperature.

In an embodiment, an integrated circuit includes: a switched capacitor coupled between a supply voltage node and a divider node, where a thermistor external to the integrated circuit is to couple to the divider node; an analog-to-digital converter (ADC) coupled to the divider node to receive a voltage at the divider node and generate a digital value based thereon; and a controller coupled to the ADC to determine a temperature associated with the thermistor based at least in part on the digital value.

A circuit device includes a digital signal processor (DSP) that performs first up-sampling processing of up-sampling up-sampling target data having a first sampling frequency from the first sampling frequency to a second sampling frequency by first interpolation processing, and an arithmetic circuit that performs second up-sampling processing of up-sampling data output from the DSP from the second sampling frequency to a third sampling frequency by second interpolation processing.

A circuit device includes a drive circuit driving a resonator, an oscillation circuit having the resonator and a variable capacitance circuit coupled to an oscillation loop including the drive circuit, and a D/A converter circuit that performs D/A conversion on frequency control data and outputs a first voltage signal and a second voltage signal which are differential signals. The variable capacitance circuit includes a first variable capacitance capacitor, to one end of which the first voltage signal is input and, to the other end of which a first bias voltage is input and a second variable capacitance capacitor, to one end of which the second voltage signal is input and, to the other end of which a second bias voltage is input.

A timing signal generation device includes a GPS receiver, an atomic oscillator, a phase comparator, a loop filter, and a divider, a temperature sensor, a DDS, and a DSP. The GPS receiver outputs a reference timing signal. The atomic oscillator outputs a clock signal in accordance with an input voltage value. The phase comparator, the loop filter, and the divider adjust the voltage value in accordance with a synchronization status between the reference timing signal and the clock signal. The temperature sensor outputs a signal depending on the temperature of the atomic oscillator. The DDS converts the frequency of the clock signal and outputs a signal obtained by converting the frequency. The DSP controls the DDS based on an output of the temperature sensor.

In an OCXO, which outputs an oscillation frequency by oscillating a crystal resonator, a correspondence relationship between an oscillation frequency and an elapsed time at a beginning after a start of oscillation of a first crystal resonator is acquired. Based on the acquired result, data after the beginning and corresponding to a correspondence relationship between an accumulated elapsed time of the oscillation and the oscillation frequency after the start of the oscillation is obtained. Based on the accumulated elapsed time of the oscillation and this data, a frequency setting value is corrected. While an output frequency of the first crystal resonator fluctuates in association with the elapsed time, the output frequency is corrected by the frequency correction value corresponding to the accumulated elapsed time, thereby stabilizing the oscillation frequency.

A MEMS resonator system has a micromechanical resonant structure and an electronic processing circuit including a first resonant loop that excites a first vibrational mode of the structure and generates a first signal at a first resonance frequency. A compensation module compensates, as a function of a measurement of temperature variation, a first variation of the first resonance frequency caused by the temperature variation to generate a clock signal at a desired frequency that is stable relative to temperature. The electronic processing circuit further includes a second resonant loop, which excites a second vibrational mode of the structure and generates a second signal at a second resonance frequency. A temperature-sensing module receives the first and second signals and generates the measurement of temperature variation as a function of the first variation of the first resonance frequency and a second variation of the second resonance frequency caused by the temperature variation.

A calibration system is provided for an oven controlled MEMS oscillator. The calibration system includes control circuitry that to separately selects predetermined target set-point values and controls a heater inside the oven controlled MEMS oscillator based on each of the selected target set-point values to adjust a set-point of the oven controlled MEMS oscillator. The system further includes an oscillation measurement circuit that measures respective oscillation frequencies at each adjusted set-point corresponding to each of the selected predetermined target set-point values. The measured oscillation frequencies can then be used to determine a target set-point operation value for the oven controlled MEMS oscillator, which can be sued to calibrate the oven controlled MEMS oscillator.