A circuit includes an oscillator having a driver and a resonator. The driver receives a supply voltage at a supply input and provides a drive output to drive the resonator to generate an oscillator output signal. A power converter receives an input voltage and generates the supply voltage to the supply input of the driver. A temperature tracking device in the power converter controls the voltage level of the supply voltage to the supply input of the driver based on temperature such that the supply voltage varies inversely to the temperature of the circuit.

A circuit includes an oscillator having a driver and a resonator. The driver receives a supply voltage at a supply input and provides a drive output to drive the resonator to generate an oscillator output signal. A power converter receives an input voltage and generates the supply voltage to the supply input of the driver. A temperature tracking device in the power converter controls the voltage level of the supply voltage to the supply input of the driver based on temperature such that the supply voltage varies inversely to the temperature of the circuit.

A circuit includes an oscillator having a driver and a resonator. The driver receives a supply voltage at a supply input and provides a drive output to drive the resonator to generate an oscillator output signal. A power converter receives an input voltage and generates the supply voltage to the supply input of the driver. A temperature tracking device in the power converter controls the voltage level of the supply voltage to the supply input of the driver based on temperature such that the supply voltage varies inversely to the temperature of the circuit.

A circuit includes an oscillator having a driver and a resonator. The driver receives a supply voltage at a supply input and provides a drive output to drive the resonator to generate an oscillator output signal. A power converter receives an input voltage and generates the supply voltage to the supply input of the driver. A temperature tracking device in the power converter controls the voltage level of the supply voltage to the supply input of the driver based on temperature such that the supply voltage varies inversely to the temperature of the circuit.

Aspects of the disclosure are directed to quadrature clock generation with injection locking. In accordance with one aspect, quadrature clock generation with injection locking uses a digital calibration circuit having a coarse calibration circuit and a fine calibration circuit to perform a coarse frequency calibration of a controlled oscillator, wherein the controlled oscillator is coupled to the digital calibration circuit; characterize a replica oscillator signal path associated with an oscillator replica circuit, wherein the oscillator replica circuit is coupled to the controlled oscillator; perform a fine frequency calibration of the controlled oscillator by measuring a phase difference between the controlled oscillator and the oscillator replica circuit; and generate a calibrated set of quadrature clock signals after performing the fine frequency calibration of the controlled oscillator.

An optoelectronic oscillator (OEO) is disclosed comprising an electronically tunable filter for transposing narrow pass band characteristics of a surface acoustic wave (SAW) filter to a microwave frequency to provide mode selection in the OEO. An OEO is disclosed comprising a set of optical domain components, a downconverter in communication with an output of the optical domain components, and a set of radio frequency (RF) domain components in communication with an output of the downconverter. The set of RF domain components comprises a tunable filter operating at a filter center frequency and having an output coupled to the set of optical domain components for communicating a mode selection result. The tunable filter including a tuner; and a sub-filter. The sub-filter operating at a fixed center frequency to provide mode selection and adjacent mode suppression with respect to the tunable filter center frequency. The sub-filter center frequency being lower than the tunable filter center frequency, and a ratio of the tunable filter center frequency to a bandwidth of the sub-filter being at least 1000:1.

A crystal oscillator and a method are provided for adjusting an oscillation frequency. The crystal oscillator includes: a first oscillator circuit, a frequency control circuit and a crystal; where the first oscillator circuit is configured to output a first drive signal having a first oscillation frequency to drive the crystal, and the frequency control circuit is configured to determine a frequency control amount according to a feature of an electrical signal flowing through the crystal under driving of the first drive signal, and adjust the first oscillation frequency according to the frequency control amount. When the technical solutions are applied to scenarios where the crystal oscillator is enabled to quickly en-oscillate, a natural en-oscillation cycle of the crystal oscillator may be shortened, and the en-oscillation speed is increased.

A semiconductor device including: a resistor element connected to one and another end of a crystal oscillator; an adjustable current type inverter element having an input connected to one end of the resistor element and an output connected to another end of the resistor element; a first capacitor element connected to the input of the inverter element and to ground; a second capacitor element having one end connected to ground; a first switching element that switches a connection state of the one end of the first capacitor element and another end of the second capacitor element; a third capacitor element connected to the output of the inverter element and to ground; a fourth capacitor element having one end connected to ground; and a second switching element that switches a connection state of the one end of the third capacitor element and another end of the fourth capacitor element.

Features and advantages of the present disclosure include a multimode voltage controlled oscillator (VCO). In one embodiment, a circuit comprises a VCO, first and second transistors, and first and second capacitive attenuators. The first and second transistors are cross coupled through the attenuators. In a first mode, the first and second transistors are turned off, and the capacitive attenuators attenuate a signal on output terminals of the VCO at control inputs of the first and second transistors. In another mode, the first and second transistors are turned on, and the capacitive attenuation is reduced or turned off so that control inputs of the first and second transistors receive signals on the outputs of the VCO.

Features and advantages of the present disclosure include a multimode voltage controlled oscillator (VCO). In one embodiment, a circuit comprises a VCO, first and second transistors, and first and second capacitive attenuators. The first and second transistors are cross coupled through the attenuators. In a first mode, the first and second transistors are turned off, and the capacitive attenuators attenuate a signal on output terminals of the VCO at control inputs of the first and second transistors. In another mode, the first and second transistors are turned on, and the capacitive attenuation is reduced or turned off so that control inputs of the first and second transistors receive signals on the outputs of the VCO.