Abstract: A phase-locked loop (PLL) including a digital PFD, a digital loop filter, a decision circuit, a fractional-N PLL, and a frequency divider is provided. The digital PFD generates a first detection signal according to the phase error or frequency difference between an input signal and a feedback signal. The digital loop filter generates a first control signal according to the first detection signal. The decision circuit generates a divisor value according to the first control signal. The fractional-N PLL generates an oscillation signal according to the divisor value and a reference signal. The frequency divider divides the oscillation signal to produce the feedback signal. The fractional-N PLL includes a fractional-N frequency divider for generating a frequency-divided signal for use in tracking the reference signal according to the divisor value by employing phase swallow means.

Abstract: An apparatus for generating an audio output clock is disclosed. The apparatus at least includes a plurality of dividers and a frequency synthesizer. The apparatus utilizes the dividers to achieve dispersive frequency-division operations such that the anti-noise ability of the apparatus can be improved. In addition, the apparatus also utilizes dynamic phase adjustment to increase accuracy of the frequency of the audio output clock.

Abstract: A switch-capacitor loop filter is used to generate a control voltage for a voltage-controlled oscillator (VCO) in a phase lock loop (PLL). The switch-capacitor circuit works in a multi-phase manner including at least two non-overlapping phases: a sampling phase and a transfer phase. During the sampling phase, the current representing the phase difference between the reference clock and the feedback clock of the PLL is integrated by a sampling capacitor. During the transfer phase, the charge stored on the sampling capacitor is transferred to a load capacitor. The timing for controlling the switch-capacitor function is derived from the reference clock.

Abstract: A phase-locked loop (PLL) for rapid lock-in applicable to digital, analog, or hybrid digital-analog PLL circuits is provided. Besides the units for basic operation, including a phase-frequency detector (PFD), a charge pump, a loop filter, and/or a voltage/current/digital-controlled oscillator (VCO/ICO/DCO), an additional lock-in actuator circuit is provided for providing lock-in signals, achieving the purpose of rapid lock-in through operational processes.

Abstract: The invention discloses an analog front end device includes a calibration unit and at least a conversion circuit. The conversion circuit includes a clamper, a multiplexer, an voltage buffer and an analog to digital converter. The clamper receives an image signal and resets the DC voltage level of the image signal to generate a clamped signal. The multiplexer receives the clamped signal and a test signal and outputs the clamped signal or the test signal according to a selecting signal. The voltage buffer amplifies the clamped signal or the test signal to generate a buffer signal. The analog to digital converter converts the buffer signal into a digital signal. The calibration unit generates a gain correction value according to the test signal and calibrates the gain offset of the digital signal according to the gain correction value.

Abstract: A digitally controlled oscillator provides high resolution in frequency tuning by using a digitally controlled capacitive network that includes a tunable capacitive circuit, a first capacitor and a second capacitor. The tunable capacitive circuit generates a variable capacitance according to a digital control word. The first capacitor is coupled in an electrically parallel configuration with the tunable capacitive circuit. The second capacitor is coupled in an electrically serial configuration with a combination of the first capacitor and the tunable capacitive circuit. The first capacitor and the second capacitor are sized such that an effective capacitance of the digitally controlled capacitor network has a step size that is a fraction of a step size of the variable capacitance in response to an incremental change in the digital control word.

Abstract: The output current of a current sink is regulated by a reference current provided by a current source and a reference voltage obtained by filtering the output voltage of the current sink. The current sink to be regulated is a voltage control current source, where the control voltage is obtained by amplifying the difference between the reference voltage and the output voltage of the current source.

Abstract: A fraction-N frequency divider includes a multi-phase clock generator, a first phase selector, a second phase selector, a glitch-free multiplexer, a control circuit, and a counter. The multi-phase clock generator is used for generating a plurality of clock signals with different phases. The first phase selector selects one of the clock signals as a first clock signal according to a first phase selecting signal. The second phase selector selects one of the clock signals as a second clock signal according to a second phase selecting signal. The glitch-free multiplexer is used for selectively outputting one of the first and second clock signals. The control circuit generates the first and second phase selecting signals and controls the clock switching timing of the glitch-free multiplexer according to a divisor setting. The counter is used for generating a frequency-divided signal according to the output of the glitch-free multiplexer.

Abstract: A phase-locked loop (PLL) including a digital PFD, a digital loop filter, a decision circuit, a fractional-N PLL, and a frequency divider is provided. The digital PFD generates a first detection signal according to the phase error or frequency difference between an input signal and a feedback signal. The digital loop filter generates a first control signal according to the first detection signal. The decision circuit generates a divisor value according to the first control signal. The fractional-N PLL generates an oscillation signal according to the divisor value and a reference signal. The frequency divider divides the oscillation signal to produce the feedback signal. The fractional-N PLL includes a fractional-N frequency divider for generating a frequency-divided signal for use in tracking the reference signal according to the divisor value by employing phase swallow means.

Abstract: The invention discloses an analog front end device includes a calibration unit and at least a conversion circuit. The conversion circuit includes a clamper, a multiplexer, an voltage buffer and an analog to digital converter. The clamper receives an image signal and resets the DC voltage level of the image signal to generate a clamped signal. The multiplexer receives the clamped signal and a test signal and outputs the clamped signal or the test signal according to a selecting signal. The voltage buffer amplifies the clamped signal or the test signal to generate a buffer signal. The analog to digital converter converts the buffer signal into a digital signal. The calibration unit generates a gain correction value according to the test signal and calibrates the gain offset of the digital signal according to the gain correction value.

Abstract: An apparatus for generating an audio output clock is disclosed. The apparatus at least includes a plurality of dividers and a frequency synthesizer. The apparatus utilizes the dividers to achieve dispersive frequency-division operations such that the anti-noise ability of the apparatus can be improved. In addition, the apparatus also utilizes dynamic phase adjustment to increase accuracy of the frequency of the audio output clock.

Abstract: A processor with an adjustable operating frequency and method thereof. The pipeline processor includes a clock providing module for providing a reference clock, and a processing core coupled to the clock providing module for processing a first instruction according to the reference clock. The clock providing module contains a multi-phase clock generator for generating a plurality of original clocks with different phases, and a phase selector for selecting an original clock to generate the reference clock according to the first instruction.

Abstract: A clock tuning device and method for executing overclocking operations on plural elements disposed on a motherboard. The clock tuning device includes a phase-locked loop for outputting a plurality of clock signals to the elements, and a control circuit for controlling the phase-locked loop to adjust the frequencies of the clock signals, so as to execute the overclocking operations on the elements, respectively. The method includes the steps of: increasing the frequency of a first clock signal until one of the elements can't work normally due to an utmost frequency of the first clock signal; resetting all the elements and operating the element corresponding to the first signal according to a safe frequency of the first clock signal; and repeating the above steps to perform overclocking operation on each of the other elements.

Abstract: A phase-locked loop (PLL) for rapid lock-in applicable to digital, analog, or hybrid digital-analog PLL circuits is provided. Besides the units for basic operation, including a phase-frequency detector (PFD), a charge pump, a loop filter, and/or a voltage/current/digital-controlled oscillator (VCO/ICO/DCO), an additional lock-in actuator circuit is provided for providing lock-in signals, achieving the purpose of rapid lock-in through operational processes.

Abstract: A switch-capacitor loop filter is used to generate a control voltage for a voltage-controlled oscillator (VCO) in a phase lock loop (PLL). The switch-capacitor circuit works in a multi-phase manner including at least two non-overlapping phases: a sampling phase and a transfer phase. During the sampling phase, the current representing the phase difference between the reference clock and the feedback clock of the PLL is integrated by a sampling capacitor. During the transfer phase, the charge stored on the sampling capacitor is transferred to a load capacitor. The timing for controlling the switch-capacitor function is derived from the reference clock.

Abstract: A phase locked loop circuit includes a phase locked loop for generating a plurality of first output signals each having a different phase but a same frequency according to a first reference signal; a control loop for generating a phase selection signal according to a second reference signal and a second output signal outputted by the phase locked loop, wherein a frequency of the second output signal is substantially equal to the frequency of the first output signals; and a phase selector for receiving the first output signals and the phase selector signal, and according to the phase selector signal selecting one of the first output signals to be a first feedback signal; wherein the first feedback signal is inputted to the phase locked loop.

Abstract: The output current of a current sink is regulated by a reference current provided by a current source and a reference voltage obtained by filtering the output voltage of the current sink. The current sink to be regulated is a voltage control current source, where the control voltage is obtained by amplifying the difference between the reference voltage and the output voltage of the current source.

Abstract: A signal generator for generating a clock with lower jitter. The signal generator includes a multi-phase clock generator for generating a plurality of multi-phase reference clocks with same frequency, a multiplexer for selecting one reference clock as an output clock according to a phase selecting signal, a phase-swallow control unit having a comparator for comparing a swallow value with a reference value out of order and outputting the comparing result as a swallow control signal, and a clock selector for receiving the swallow control signal and generating the phase selecting signal. Because the reference value is provided by a counter in bit-reversed, the swallow control signal is dispersed smoothly and the jitter of the output clock is reduced.

Abstract: A processor with an adjustable operating frequency and method thereof. The pipeline processor includes a clock providing module for providing a reference clock, and a processing core coupled to the clock providing module for processing a first instruction according to the reference clock. The clock providing module contains a multi-phase clock generator for generating a plurality of original clocks with different phases, and a phase selector for selecting an original clock to generate the reference clock according to the first instruction.

Abstract: A symmetric electrical connection system for balancing impedance between a first node and a third node and impedance between a second node and a fourth node. The system includes a first conducting wire, a third conducting wire, a fifth conducting wire, and a seventh conducting wire all installed in a first layer. The system further includes a second conducting wire, a fourth conducting wire, a sixth conducting wire, and an eighth conducting wire all installed in a second layer. The first conducting wire and the eighth conducting wire are crossed but electrically insulated. The second conducting wire and the third conducting wire are crossed but electrically insulated. The fourth conducting wire and the fifth conducting wire are crossed but electrically insulated. The sixth conducting wire and the seventh conducting wire are crossed but electrically insulated. In a preferred embodiment, the appearances and the materials of the conducting wires are essentially equivalent.