An oscillator includes a container, an oscillation element housed in the container, a heating circuit housed in the container, and adapted to control a temperature of the oscillation element, a temperature detection circuit housed in the container, a temperature control circuit housed in the container, and adapted to control the heating circuit based on an output of the temperature detection circuit, at least one connecting wire housed in the container, and electrically connects a ground of the temperature detection circuit and a ground of the temperature control circuit to each other, and a ground external terminal disposed on an outer surface of the container, and electrically connected to the ground of the temperature detection circuit and the ground of the temperature control circuit.

A frequency drift detector includes a frequency-to-voltage converter, FVC, arranged to receive a reference frequency signal and configured to generate an FVC output voltage. The frequency drift detector also includes a voltage regulator arranged to output at least one regulated voltage; and a voltage comparator coupled to an output of the FVC and an output of the voltage regulator. The voltage comparator is arranged to compare the FVC output voltage and the at least one regulated voltage and generate an error signal in response to determining that the FVC output voltage exceeds a frequency drift level indicated by the at least one regulated voltage.

Systems and processes disclosed herein determine the temperature of a crystal, such as a crystal that may be used in a crystal oscillator, using the reference crystal itself. The system can measure the temperature of the crystal without a temperature sensor. Further, a single oven technique may be used to maintain the temperature of the reference crystal. Thus, in certain embodiments, a more compact crystal oscillator can be generated compared to conventional techniques. Further, by measuring the reference crystal based on signals generated by the reference crystal itself, the system disclosed herein is more accurate than many previous crystal oscillator systems.

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.

Systems and methods for digital synthesis of an output signal using a frequency generated from a resonator and computing amplitude values that take into account temperature variations and resonant frequency variations resulting from manufacturing variability are described. A direct frequency synthesizer architecture is leveraged on a high Q resonator, such as a film bulk acoustic resonator (FBAR), a spectral multiband resonator (SMR), and a contour mode resonator (CMR) and is used to generate pristine signals.

This disclosure provides a method and apparatus for a temperature-compensated oscillator. In some example implementations, the temperature-compensated oscillator may include a first oscillator, a second oscillator, and a temperature compensation block. The first oscillator may generate a first periodic clock signal and the second oscillator may generate a second periodic clock signal. The temperature-compensating block may generate a compensation signal based on the first period clock signal and the second periodic clock signal.

Temperature-independent clock generation systems and methods are described that include a trained neural network coupled to a frequency correction circuit that corrects a crystal resonator output of a clock signal having a frequency that changes with changes in temperature. The neural network is trained with test temperatures and corresponding temperature based changes in frequency for test resonators of the same type as the resonator of the real time clock. The neutral network is trained to output frequency corrections based on a set of measured reference temperature-based changes in frequency for the crystal resonator and a current temperature of the resonator. The frequency correction circuit receives the frequency corrections from the neural network and corrects changes in the frequency caused by the changes in temperature of the resonator to provide a clock signal having an output frequency that is independent of the current temperature of the resonator.

Systems and methods for digital synthesis of an output signal using a frequency generated from a resonator and computing amplitude values that take into account temperature variations and resonant frequency variations resulting from manufacturing variability are described. A direct frequency synthesizer architecture is leveraged on a high Q resonator, such as a film bulk acoustic resonator (FBAR), a spectral multiband resonator (SMR), and a contour mode resonator (CMR) and is used to generate pristine signals.

An example resonating structure comprises a substrate, a resonator body, and an anchoring body for anchoring the resonator body to the substrate. The resonator body includes a layer of base material and, deposited on top of the layer of base material, a layer of mismatch material having a mismatch in temperature coefficient of elasticity (TCE) relative to the base material. The base material is doped with a dopant having a concentration chosen so as to minimize a second order temperature coefficient of frequency for the resonator body. The thickness of the layer of the mismatch material is chosen so as to minimize a first order temperature coefficient of frequency for the resonator body.

An oscillator includes a resonator, an oscillation circuit, and first and temperature compensation circuits. The first temperature compensation circuit performs a first-order first temperature compensation processing in a first mode and performs the first-order first temperature compensation processing and a high-order first temperature compensation processing in a second mode for a frequency of a first clock signal generated by oscillation of the resonator by the oscillation circuit. The second temperature compensation circuit receives the first clock signal and outputs a second clock signal subjected to a high-order second temperature compensation processing based on the first clock signal.