Abstract: A frequency generating circuit includes: a delay circuit, arranged to operably delay an output frequency signal to generate a delayed signal; a quartz crystal resonator, coupled with the delay circuit, arranged to operably conduct a band-pass filtering operation on the delayed signal to generate the output frequency signal; and a delay control circuit, coupled with the delay circuit, arranged to operably control a phase delay amount of the delay circuit to thereby control the phase of the delayed signal.

Abstract: A frequency generating circuit includes: a delay circuit, arranged to operably delay an output frequency signal to generate a delayed signal; a quartz crystal resonator, coupled with the delay circuit, arranged to operably conduct a band-pass filtering operation on the delayed signal to generate the output frequency signal; and a delay control circuit, coupled with the delay circuit, arranged to operably control a phase delay amount of the delay circuit to thereby control the phase of the delayed signal.

Abstract: A frequency generating circuit includes: a differential delay circuit arranged to operably delay an input signal to generate a first delayed signal and a second delayed signal; a quartz crystal resonator arranged to operably conduct a band-pass filtering operation on one of the first and second delayed signals to generate a frequency signal; a compensation capacitor, coupled between another output of the differential delay circuit and an output of the quartz crystal resonator, arranged to operably suppress noise in the frequency signal; an oscillator arranged to operably generate an oscillating signal under control of a control signal; a frequency divider arranged to operably conduct a frequency-dividing operation on the oscillating signal to generate the input signal; and a feedback control circuit arranged to operably generate the control signal according to the frequency signal.

Abstract: A modulator for generating a control code in response to a frequency control word is provided. The modulator includes an adder, an accumulator, a next state generation unit, and a code generation unit. The adder generates a frequency error signal by calculating a difference between the frequency control word and the control code. The accumulator generates a phase error signal by accumulating the frequency error signal. The phase error signal includes an integer part and a fractional part. The integer part of the phase error signal is a current state signal. The next state generation unit generates a next state signal according to a characteristic probability distribution determined by the fractional part of the phase error signal. The code generation unit generates the control code in response to the current state signal and the next state signal.

Abstract: A modulator for generating a control code in response to a frequency control word is provided. The modulator includes an adder, an accumulator, a next state generation unit, and a code generation unit. The adder generates a frequency error signal by calculating a difference between the frequency control word and the control code. The accumulator generates a phase error signal by accumulating the frequency error signal. The phase error signal includes an integer part and a fractional part. The integer part of the phase error signal is a current state signal. The next state generation unit generates a next state signal according to a characteristic probability distribution determined by the fractional part of the phase error signal. The code generation unit generates the control code in response to the current state signal and the next state signal.

Abstract: A digitally controlled oscillator includes a ring oscillator and a first supplementary circuit. The ring oscillator is coupled to a supply voltage and generates a signal oscillated at an oscillating frequency. The oscillating frequency is controlled by a digital code and further varies with a supply voltage drift in a first direction. The first supplementary circuit is coupled to the ring oscillator and facilitates the oscillating frequency to vary with the supply voltage drift in a second direction reverse to the first direction.

Abstract: A circuit for controlling a mixed mode controlled oscillator. The circuit comprises a charge pump, and a digital loop filter. The charge pump is coupled to the mixed mode controlled oscillator. The charge pump receives an up/down signal and sends a current signal to the mixed mode controlled oscillator. The digital loop filter receives the up/down signal and generates a digital code signal to the mixed mode controlled oscillator. An output frequency of the mixed mode controlled oscillator is controlled by the current signal and the digital code signal.

Abstract: A calibration device arranged for calibrating an oscillating frequency of an oscillator includes: a phase locking device arranged to track a first reference clock generated by the oscillator until a feedback clock is phase-aligned with the first reference clock, and then arranged to track a second reference clock generated by the oscillator until a phase difference between the second reference clock and the feedback clock is a static phase difference, wherein the feedback clock is generated by dividing an output oscillating signal of the phase locking device by a divisor; an adjusting circuit arranged to adjust the divisor into an updated divisor to reduce the static phase difference between the second reference clock and the feedback clock; and a calibrating circuit arranged to calibrate the oscillating frequency of the oscillator according to the updated divisor, wherein the second reference clock is generated by varying a control signal of the oscillator.

Abstract: A digitally controlled oscillator includes a ring oscillator and a first supplementary circuit. The ring oscillator is coupled to a supply voltage and generates a signal oscillated at an oscillating frequency. The oscillating frequency is controlled by a digital code and further varies with a supply voltage drift in a first direction. The first supplementary circuit is coupled to the ring oscillator and facilitates the oscillating frequency to vary with the supply voltage drift in a second direction reverse to the first direction.

Abstract: A transmitter is provided. The transmitter includes a phase/frequency deviation input, a controller and a frequency modulating path. The phase/frequency deviation input receives multiple phase/frequency deviation samples. The controller outputs a modified phase/frequency deviation signal and generates a phase/frequency deviation carry-out signal in response to the phase/frequency deviation samples and a previous time sample of the phase/frequency deviation carry-out signal. The frequency modulating path performs frequency modulation in response to the modified phase/frequency deviation signal and outputs a frequency modulated carrier signal.

Abstract: Clock generators are provided. A phase locked loop generates an output clock, a delay line is coupled to an input of the phase locked loop, and a modulation unit integrates an input signal with a constant level to generate a modulation signal controlling the delay line, thereby modulating a phase of a first input clock of the phase locked loop, such that frequency of the output clock is locked at a desired frequency.

Abstract: A calibration device arranged for calibrating an oscillating frequency of an oscillator includes: a phase locking device arranged to track a first reference clock generated by the oscillator until a feedback clock is phase-aligned with the first reference clock, and then arranged to track a second reference clock generated by the oscillator until a phase difference between the second reference clock and the feedback clock is a static phase difference, wherein the feedback clock is generated by dividing an output oscillating signal of the phase locking device by a divisor; an adjusting circuit arranged to adjust the divisor into an updated divisor to reduce the static phase difference between the second reference clock and the feedback clock; and a calibrating circuit arranged to calibrate the oscillating frequency of the oscillator according to the updated divisor, wherein the second reference clock is generated by varying a control signal of the oscillator.

Abstract: Spread spectrum generators and methods are disclosed. In one implementation, a spread spectrum clock generator includes a phase locked loop generating an output clock according to a first clock and a second clock; a delay line coupled between the first clock and the phase locked loop; a modulation unit providing a modulation signal to control the delay line thereby modulating phase of the first clock, such that frequency of the output clock generated by the phase locked loop varies periodically; a scaling unit scaling the modulation signal from the modulation unit according to a scaling ratio, and outputting to the delay line; and a calibration unit generating an output signal for controlling the scaling ratio.

Abstract: A voltage converter for converting an analog input signal into a digital signal is provided. The pulse width of the digital signal is relative to the voltage level of the analog input signal. The voltage converter includes a comparator and a feedback module. After comparing the analog input signal and an analog feedback signal, the comparator generates the digital signal. When the analog input signal is higher than the analog feedback signal, the digital signal has a first voltage level. When the analog input signal is lower than the analog feedback signal, the digital signal has a second voltage level, which is different from the first voltage level. Based on the digital signal, the feedback module adjusts the analog feedback signal toward the analog input signal.

Abstract: An oscillating circuit including a digital sigma-delta modulator and a controlled oscillator is disclosed. The digital sigma-delta modulator receives a fractional bit signal to generate a control signal. The controlled oscillator includes a varactor dynamically coupled to receive the control signal.

Abstract: A transmitter is provided. The transmitter includes a phase/frequency deviation input, a controller and a frequency modulating path. The phase/frequency deviation input receives multiple phase/frequency deviation samples. The controller outputs a modified phase/frequency deviation signal and generates a phase/frequency deviation carry-out signal in response to the phase/frequency deviation samples and a previous time sample of the phase/frequency deviation carry-out signal. The frequency modulating path performs frequency modulation in response to the modified phase/frequency deviation signal and outputs a frequency modulated carrier signal.

Abstract: An analog-to-digital converter including a comparator, a control module, a voltage adjusting module, and an evaluating module is provided. The comparator compares an analog input voltage with a feedback voltage and generates a comparison result. Based on the comparison result, the control module generates a control signal. The voltage adjusting module increases or decreases the feedback voltage toward the analog input voltage according to the control signal. The voltage increase amount and decrease amount provided by the voltage adjusting module are corresponding to a first digital value and a second digital value, respectively. The evaluating module generates the first digital value and the second digital value based on the control signal. According to the first digital value and the second digital value, a digital signal corresponding to the analog input voltage is generated.

Abstract: Spread spectrum clock generators. A phase lock loop generates an output clock according to a first input clock and a second input clock, a delay line is coupled between the first input clock and the phase lock loop. A modulation unit provides a modulation signal to control the delay line thereby modulating phase of the first input clock, such that frequency of the output clock generated by the phase lock loop varies periodically.

Abstract: Phase locked loop circuits are provided, in which a phase locked loop module includes a voltage controlled oscillator to generate an oscillation signal with an output frequency according to a control voltage, and a gain calibration module triggers the phase locked loop module to induce a frequency variation characterized by a delta function in the output frequency and calculates a gain of the voltage controlled oscillator according to a phase error caused by the frequency variation in the output frequency.

Abstract: A circuit for controlling a mixed mode controlled oscillator. The circuit comprises a charge pump, and a digital loop filter. The charge pump is coupled to the mixed mode controlled oscillator. The charge pump receives an up/down signal and sends a current signal to the mixed mode controlled oscillator. The digital loop filter receives the up/down signal and generates a digital code signal to the mixed mode controlled oscillator. An output frequency of the mixed mode controlled oscillator is controlled by the current signal and the digital code signal.