Systems, methods, and devices of the present disclosure relate, generally, to compensating for frequency error of a reference signal supplied to a clock-tracking-loop due to temperature. Error characteristics of a crystal oscillator that supplies the reference signal are used to compensate for possible frequency errors. Other systems, methods and devices are disclosed.

A clock generating circuit includes a dividing unit and a distribution unit. The dividing unit divides a reference clock to generate a divided clock, and the divided clock has a frequency of 1/N times of a frequency of the reference clock, where N is an integer of two or more. The distribution unit distributes the reference clock to a first route and a second route, the first route includes an output terminal that outputs a clock with a frequency identical to the frequency of the reference clock, and the second route includes the dividing unit. The dividing unit includes one or more amplifiers, one or more dividing circuits, and a correction circuit. The correction circuit is disposed between the amplifier and the dividing circuit, and the correction circuit corrects a level of an input clock input to the dividing circuit.

A temperature compensated oscillation controller includes a temperature compensation circuit configured to provide a reference voltage through a first terminal and to receive an input voltage including temperature information through a second terminal, and an oscillation circuit configured to be connected to an external crystal resonator through third and fourth terminals and to output a clock signal in response to an oscillation signal from the external crystal resonator. The temperature compensation circuit is configured to perform a voltage controlled oscillator-based sensing operation to convert the input voltage into a temperature code and to adjust a frequency of the clock signal using the temperature code.

A circuit device includes a control voltage input terminal to which a control voltage is inputted, an A/D conversion circuit A/D-converting the control voltage to generate control voltage data and A/D-converting a temperature detection voltage from a temperature sensor to generate temperature detection data, a processing circuit generating temperature compensation data of an oscillation frequency based on the temperature detection data and performing addition processing of the temperature compensation data and the control voltage data to generate frequency control data of the oscillation frequency, and an oscillation signal generation circuit generating an oscillation signal of the oscillation frequency set by the frequency control data, using the frequency control data and a resonator.

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 circuit includes: a first resonator; a temperature compensation circuit including a resonator group-delay analyzer and a second resonator; oscillator control circuitry; and a controller. The resonator group-delay analyzer is configured to determine a group-delay parameter responsive to operations of the second resonator. The controller is configured to provide a control signal responsive to the group-delay parameter. The oscillator control circuitry is configured to adjust a frequency of an output signal of the oscillator control circuitry responsive to the control signal.

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.

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.

A temperature compensated crystal oscillator (TCXO) includes a crystal oscillator and a temperature sensor to provide a sensed temperature. A delay circuit has a selectable delay to delay the frequency compensation based on the sensed temperature. The delay compensates for a difference between when the temperature sensor reflects a change in temperature and when a frequency of a signal supplied by the crystal oscillator is affected by the change in temperature. The delay may be static or dynamic with respect to the current temperature sensed by the temperature sensor.

An oscillator and method for maintaining a phase lock is provided. The oscillator may include an oscillator input port for receiving a reference signal, an oscillator output port for outputting an oscillator output, an unlocked oscillator oscillating in an unlocked state and outputting at a resonance frequency configured to drift in response to changes in an operating environment, and a phase locked loop (PLL) including a mixer having an output port configured to output the unlocked oscillator output mixed with a local oscillator output, the mixer output port in communication with a phase frequency detector and the oscillator output port, and the phase frequency detector generating a control signal based on a detected phase difference between the reference signal and the mixer output wherein the control signal adjusts the local oscillator output to compensate for the resonance frequency drift of the unlocked oscillator when mixed with the unlocked oscillator output.