According to an embodiment, a voltage-controlled oscillator has a variable capacitive element with a capacitance that is changed by a voltage to be applied thereto. One electrode of the variable capacitive element is connected to a control input terminal where a control voltage that controls an oscillation frequency is applied thereto. It has a compensation voltage generation circuit that generates a voltage that changes with a temperature thereof. It has a resistive element with one end that is directly connected to another electrode of the variable capacitive element and another end that is supplied with an output voltage of the compensation voltage generation circuit.

A wide range differential current switching circuit can operate across a wide range of input currents and across a broad range of frequencies. A first differential current source can include a first transistor and a second transistor. The first transistor receives a switching signal and provides an output current and at output node. The second transistor receives an inverted switching signal, the first transistor and the second transistor coupled to each other at a tail node. A current source provides an input current to the tail node. A third transistor can provide a boost current to the tail node while the first transistor is off.

Provided is an oscillation apparatus and an oscillation control apparatus including a first control section that generates a first control signal that controls an oscillation frequency of an oscillator, based on a temperature detection result of a temperature detecting section; an encoder that generates a feedback signal; a second control section that generates a second control signal that controls the oscillation frequency of the oscillator, based on the temperature detection result of the temperature detecting section, an external input signal input from outside, and the feedback signal; an oscillation circuit that sets the oscillation frequency of the oscillator, based on the first control signal and the second control signal; and a reference voltage generating section that generates a reference voltage, wherein the encoder generates the feedback signal by comparing the second control signal and the reference voltage.

A wide range differential current switching circuit can operate across a wide range of input currents and across a broad range of frequencies. A first differential current source can include a first transistor and a second transistor. The first transistor receives a switching signal and provides an output current and at output node. The second transistor receives an inverted switching signal, the first transistor and the second transistor coupled to each other at a tail node. A current source provides an input current to the tail node. A third transistor can provide a boost current to the tail node while the first transistor is off.

An oscillator includes a case that has a base and a cap connected to the base; a first substrate accommodated in the case; a lead terminal electrically connected to the first substrate; and a resonator module electrically connected to the lead terminal and supported by the lead terminal with a gap with respect to the first substrate between the first substrate and the base.

An oscillator includes a vibrator element, a container in which the vibrator element is housed, at least one of a heating element and a cooling body configured to control the temperature on the inside of the container, an oscillation circuit electrically connected to the vibrator element, a D/A conversion circuit configured to control a frequency output by the oscillation circuit, and a reference-voltage generation circuit configured to supply a voltage to the D/A conversion circuit. The reference-voltage generation circuit is mounted on the inside of the container or on a substrate on which the container is mounted.

According to an embodiment, a voltage-controlled oscillator has a variable capacitive element with a capacitance that is changed by a voltage to be applied thereto. One electrode of the variable capacitive element is connected to a control input terminal where a control voltage that controls an oscillation frequency is applied thereto. It has a compensation voltage generation circuit that generates a voltage that changes with a temperature thereof. It has a resistive element with one end that is directly connected to another electrode of the variable capacitive element and another end that is supplied with an output voltage of the compensation voltage generation circuit.

An oscillator includes a resonator; an oscillation circuit which oscillates the resonator; a D/A conversion circuit which receives digital data for controlling a frequency of the oscillation circuit; a first temperature sensor; and a temperature compensation circuit which is connected to the first temperature sensor. The oscillation circuit includes a first variable capacitor element and a second variable capacitor element. An output voltage of the D/A conversion circuit is applied to the first variable capacitor element. An output voltage of the temperature compensation circuit is applied to the second variable capacitor element.

A device comprising: a voltage reference supply, configured to provide a reference voltage that varies in response to temperature according to a predefined relationship; a temperature sensor providing a temperature signal indicating a temperature; a first controller configured to receive the temperature signal and to output a control signal; an LC-DCO receiving the reference voltage and providing an output signal with a frequency from an LC circuit, the LC-DCO comprising a switched capacitor bank configured to provide temperature compensation by varying an effective capacitance in the LC circuit in response to the control signal.

An oscillation circuit includes an amplification circuit that causes a resonator to oscillate, and a variable capacitance circuit whose capacitance value is controlled on the basis of a control voltage. The variable capacitance circuit includes a first variable capacitive element in which an inflection point voltage in a change characteristic of a capacitance value for the control voltage is a first voltage, and a second variable capacitive element in which an inflection point voltage in a change characteristic of a capacitance value for the control voltage is a second voltage which is different from the first voltage. A capacitance value of the first variable capacitive element when the control voltage is the first voltage is different from a capacitance value of the second variable capacitive element when the control voltage is the second voltage.