Abstract: A delay locked loop (DLL) circuit includes a first delay control unit configured to generate a first delay control signal in response to a first phase detection signal to control a delay amount of a first delay line and to output a first delay amount information signal, a second delay control unit configured to generate a second delay control signal in response to a second phase detection signal to control a delay amount of a second delay line and to output a second delay amount information signal, and to control the delay amount of the second delay line again in response to the first delay control signal and a half cycle information signal, a half cycle detecting unit configured to receive the first delay amount information signal and the second delay amount information signal to extract half cycle information of a reference clock signal, thereby generating the half cycle information signal, and a duty cycle correcting unit configured to combine an output clock signal from the first delay line and an output

Abstract: An All Digital PLL (ADPLL) and oscillation signal generation method using the ADPLL is provided for generating a spur-free oscillation signal by improving the frequency resolution of the ADPLL.

Abstract: The present invention relates to a digital offset phase-locked loop (DOPLL), which may have advantages of size, simplicity, performance, design portability, or any combination thereof, compared to analog-based phase-locked loops (PLLs). The DOPLL may include a digital controlled oscillator (DCO), which provides a controllable frequency output signal based on a digital control signal, a radio frequency (RF) mixer circuit, which provides a reduced-frequency feedback signal based on the controllable frequency output signal without reducing loop gain, a time-to-digital converter (TDC), which provides a digital feedback signal that is a time representation of the reduced-frequency feedback signal, and digital PLL circuitry, which provides the digital control signal based on the digital feedback signal and a digital setpoint signal.

Abstract: Device and method for temperature compensation in a clock oscillator using quartz crystals, which integrates dual crystal oscillators. The minimal power consumption is achieved through an efficient use of a processor in charge of the synchronization of the two oscillators. The invention is particularly adapted for the provision of a precise reference clock in portable radiolocalization devices.

Abstract: Methods and apparatus are provided for calibrating a voltage controlled oscillator, such as an N-stage voltage controlled ring oscillator. The voltage controlled oscillator comprises a power supply input and at least one gate delay element and has a frequency that is a function of a delay of the gate delay element and a voltage applied to the power supply input. A voltage controlled oscillator is calibrated by varying an output voltage of a programmable voltage source through a range of values; applying the output voltage to the power supply input of the voltage controlled oscillator; comparing an output clock frequency of the voltage controlled oscillator to a reference frequency clock for each of the output voltage values; and selecting a value of the output voltage that provides an approximate minimum frequency difference between the output clock frequency and the reference frequency clock.

Abstract: A phase locked loop has a digitally controlled oscillator (DCO) for generating a DCO output signal (fOSC), a clock divider coupled to the DCO and receiving the DCO output signal and outputting a feedback clock signal (fN), and a phase frequency detector (PFD) coupled to the DCO and controlling the DCO by a DCO control signal (dCNTL).

Abstract: Exemplary embodiments of the invention provide a system, method and apparatus for spread spectrum functionality for a free-running, reference harmonic oscillator. In an exemplary embodiment, an apparatus comprises a reference oscillator adapted to provide a reference signal having a reference frequency; and a spread spectrum controller adapted to control the reference oscillator to generate a spread-spectrum reference signal at a plurality of different reference frequencies during a predetermined or selected time period. An exemplary apparatus may also include a coefficient register adapted to store a plurality of coefficients and a plurality of controlled reactance modules responsive to a corresponding coefficient of the plurality of coefficients to modify an amount of reactance effectively coupled to the reference oscillator.

Abstract: Disclosed is a system and method for providing an oscillating signal of relatively precise frequency without using a signal provided by a crystal as a reference. Disclosed is a feedback oscillator circuit configured to output an oscillating signal having a frequency defined by a reference signal. The oscillating signal can be sent to one or more circuits including at least one frequency sensitive element. The frequency sensitive element produces an output signal which depends on the frequency of the oscillating signal. A controller controls the reference signal in order to cause an attribute of the output signal to have a value within a desired range.

Abstract: In an embodiment, a circuit is provided comprising a multi-phase oscillator configured to output a plurality of output signals having the same frequency and different phase offsets. A feedback value is generated based on at least two of said output signals. A reference value is generated based on a reference clock and a predetermined value. The reference value and the feedback value are combined.

Abstract: In an embodiment, a circuit comprising an oscillator is provided. The oscillator is controlled based on a feedback value and an input reference value. The feedback value or the reference value or both are generated using noise shaping.

Abstract: Apparatuses, methods, systems, algorithms, and circuits for reference clock frequency determination are disclosed. In one embodiment, a circuit for detecting a reference clock frequency can include a clock counter configured to count a number of cycles of the reference clock over a predetermined portion of a sleep clock to provide a reference clock cycle count, where the sleep clock has a known frequency and a predetermined accuracy; a frequency estimator configured to estimate the reference clock frequency from the reference clock cycle count and the known frequency of the sleep clock; and a frequency selector configured to select a closest frequency to the estimated reference clock frequency from a plurality of allowed frequencies.

Abstract: A frequency locking structure applied to phase-locked loops (PLL) utilizes a common factor to reduce the difference between an output signal of oscillation and an input signal of reference for the jitter reduction of the input signal of reference. Moreover, a count value of clock signal is an input of a greatest-common-factor calculator to acquire an adaptive value and a feedback adaptive value for the common factor of a divider. Such a frequency locking structure both prevents the PLL from being in error about outputting frequency and dynamically adjusts the common factors for different purposes.

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: A method for controlling a frequency output of a phase locked loop (PLL) is provided. The method includes providing digital control words to the PLL to discretely change at least one dividing factor within the PLL. The method further includes applying a time-varying control voltage to a voltage controlled oscillator. The method still further includes applying an output of the voltage controlled oscillator to the PLL as a reference frequency. The method further includes outputting a signal from the PLL, the signal varied in frequency based on one or more of the time-varying control voltage and the at least one dividing factor.

Abstract: A PLL frequency synthesizer 1 according to one embodiment of the present invention is provided with a frequency divider 30, a phase comparator 40, a charge pump 50, a loop filter 60, a voltage controlled oscillator 70, and a changeover switch (within the switching unit 80). The loop filter 60 has a reference potential on a semiconductor substrate as a ground potential, and the changeover switch is formed on the semiconductor substrate 2 and switches connection between an intermediate node of the loop filter 60 and the reference potential on the semiconductor substrate 2 to switch the time constant of the loop filter 60.

Abstract: A direct digital frequency synthesizer having a multi-modulus divider, a numerically controlled oscillator and a programmable delay generator. The multi-modulus divider receives an input clock having an input pulse frequency fosc and outputs some integer fraction of those pulses at an instantaneous frequency fVp that is some integer fraction (1/P) of the input frequency. The multi-modulus divider selects between at least two ratios of P(1/P or 1/P+1) in response to a signal from the numerically controlled oscillator. The numerically controlled oscillator receives a value which is the accumulator increment (i.e. the number of divided pulse edges) required before an overflow occurs that causes the multi-modulus divider to change divider ratios in response to receiving an overflow signal.

Abstract: A mixed-signal chip is described. The mixed-signal chip comprises a first portion of analog circuit and second portion of digital circuit, an on-chip precision oscillator residing on the first analog portion, the precision oscillator has a precision frequency; a first on-chip non-precision tunable oscillator from a first clock domain residing on the first analog portion, the first non-precision tunable oscillator has a first adjustable frequency; a noise detector for detecting a first noise in the first clock domain; a frequency adjusting register for storing a first desired frequency value of the first on-chip non-precision tunable oscillator, wherein the first desired frequency value is determined based on the first detected noise; a control circuit for adjusting the adjustable frequency of the first non-precision tunable oscillator to the first desired frequency value by using the precision frequency of the on-chip precision oscillator as a reference.

Abstract: A DPLL circuit is provided for making it possible to inhibit an initial frequency offset during holdover. The DPLL circuit includes a slave oscillator for generating a frequency signal corresponding to the size of a control signal value; a phase difference detection circuit for detecting the difference in phase between the output of said slave oscillator and the inputted reference clock, and outputting a digital signal of the prescribed number of bits corresponding to said detected phase difference; and a holdover unit for generating a correction value based on the output of said phase difference detection circuit, wherein when the holdover is detected, said holdover unit periodically adds the correction value to the output of said phase difference detection circuit to obtain a control value for said slave oscillator.

Abstract: Techniques for mitigating VCO pulling are described. In an aspect, VCO pulling may be mitigated by (i) injecting an oscillator signal, which is a version of a VCO signal from a VCO, into a transmitter and (ii) using coupling paths from the transmitter to the VCO to re-circulate the oscillator signal back to the VCO. In one design, an apparatus includes a VCO and a coupling circuit. The VCO generates a VCO signal at N times a desired output frequency. The coupling circuit receives an oscillator signal generated based on the VCO signal and injects the oscillator signal into a transmitter to mitigate pulling of the frequency of the VCO due to undesired coupling from the transmitter to the VCO. The apparatus may include a phase adjustment circuit that adjusts the phase of the oscillator signal and/or an amplitude adjustment circuit that adjusts the amplitude of the oscillator signal.

Abstract: Systems and methods for enabling the determination of voltage controlled oscillator (VCO) linearity, duty cycle determination and duty cycle correction in phase locked loop circuits (PLL's.) One embodiment comprises a method including the steps of determining the frequency response of a PLL's VCO as a function of duty cycle, applying a signal based on the VCO output to the VCO input, measuring the resulting frequency of the VCO output signal, determining the duty cycle corresponding to the measured frequency, and configuring a duty cycle correction unit correct the duty cycle of the VCO output signal to about 50%. Determining the frequency response of the VCO may include, for each of several different duty cycle values between 0% and 100%, applying the VCO input signal to the VCO and determining the corresponding frequency of the VCO output signal. This may also be done for duty cycles of 0% and 100%.

Abstract: A digital phase locked loop includes a phase acquisition unit for producing a digital representation of the phase of a reference signal, a digital phase detector having a first input receiving a digital signal from, or derived from, the output of the phase acquisition unit, digital loop filter filtering the output of the digital phase detector, and a digital controlled oscillator generating an output signal under the control of the digital loop filter. A digital feedback loop provides a second input to the digital phase detector from the output of the digital controlled oscillator.

Abstract: Implementations feature systems and techniques for phase-locked loops (PLLs). In some aspects, implementations feature a system that has a PLL circuit including an oscillator and programmable reference frequency divider circuit or a programmable feedback frequency divider circuit. The PLL includes a control circuit to reduce a time required for a PLL settling time by programming a division value into the programmable reference frequency divider circuit and/or the programmable feedback frequency divider circuit to target the oscillator to operate outside of a system operating frequency range of the oscillator during start-up of PLL operations. The control circuit can program another division value into the programmable reference frequency divider circuit and/or the programmable feedback frequency divider circuit after stabilization of the variable oscillator.

Abstract: A digitally-controlled oscillator (DCO) of a PLL is dithered such that a DCO_OUT signal has a frequency that changes at dithered intervals. In one example, the DCO receives an undithered stream of incoming digital tuning words, and receives a dithered reference clock signal REFD, and outputs the DCO_OUT signal such that its frequency changes occur at dithered intervals. Where the PLL is employed in the local oscillator of a cellular telephone transmitter, the novel dithering of the DCO spreads digital image noise out in frequency such that less digital image noise is present at a particular frequency offset from the main local oscillator frequency. Spreading digital image noise out in frequency allows a noise specification to be met without having to increase the frequency of the PLL reference clock. By avoiding increasing the frequency of the reference clock to meet the noise specification, increases in power consumption are avoided.

Abstract: A circuit includes a DDS unit deriving a sine wave from a tuning word using a frequency of a reference clock, a first frequency divider dividing the frequency of the reference clock, a second frequency divider dividing a frequency of the sine wave output by the DDS unit, and a mixer mixing the sine wave of a divided frequency with the reference clock of a divided frequency to thus produce the sine wave of a mixed frequency.

Abstract: A digital phase locked loop includes a phase acquisition unit receiving a sampled input signal and applying its output to a first input of a digital phase detector, a digital controlled oscillator producing a digital output, and a feedback path coupling the digital output of the digital controlled oscillator to a second input of the digital phase detector in the digital domain. The input signal may be sampled asynchronously.

Abstract: A system comprises a primary oscillator that provides a first signal having a first phase and a backup oscillator that provides a second signal having a second phase. The system also comprises trim logic coupled to the backup oscillator logic. Prior to failure of the primary oscillator, the trim logic adjusts the second phase to match the first phase. Upon failure of the primary oscillator, the second signal is used in lieu of the first signal.

Abstract: A frequency synthesizer is built using a phase locked loop incorporating a single side band mixer either in the feedback loop or in the input. The single side band mixer is preferably realized with digital logic and FETs, and the resulting frequency synthesizer simultaneously improves control over the frequency resolution, noise floor and operating frequency range.

Abstract: A phase-locked loop includes a processing unit, a voltage-controlled oscillator, and a control unit. The processing unit generates a control voltage to a node according to a phase difference between a reference clock and a first feedback clock. The voltage-controlled oscillator generates the first feedback clock according to a voltage of the node. The control unit deactivates the voltage-controlled oscillator and provides a start voltage to the node in a power-down mode, and activates the voltage-controlled oscillator to generate the first feedback clock according to the voltage of the node in a power-on mode. The control unit stops providing the start voltage in the power-on mode.

Abstract: A frequency synthesizer is built using a phase locked loop incorporating a single side band mixer in the input. The single side band mixer is preferably realized with digital logic and FETs, and the resulting frequency synthesizer simultaneously improves control over the frequency resolution, noise floor and operating frequency range.

Abstract: System and method for generating multiple local oscillator signals comprising a first-stage phase-locked loop (PLL) having an input to receive a first reference signal input and having an output to transmit a second reference signal, wherein the second reference signal is an integer or fractional multiple of the first reference signal; and a plurality of second-stage PLLs, each second-stage PLL having an input coupled to the output of the first-stage PLL and receiving the second reference signal, and each second-stage PLL having an output for transmitting a local oscillator signal, wherein each of the local oscillator signals is an integer multiple of the second reference signal.

Abstract: An apparatus includes an oscillator, a memory for storing data of a first frequency and of a first voltage, a first controller for causing the oscillator to generate a clock having a required frequency by applying a voltage on the basis of the data of the first frequency and of the first voltage, a second controller for causing the oscillator to generate a clock having a second frequency by applying a second voltage at predetermined timing, an output section for outputting data of the clock of the second frequency to a frequency counter, a writing section for updating the data of the first voltage to data of the second voltage and the data of the first frequency to data of the second frequency when a difference between the second frequency and a third frequency is within a predetermine range.

Abstract: The Field Programmable Hybrid Array (FPHA) and Frequency Programmable Xtaless Clock (FPXC) are for high-speed and high frequency System-Design-On-Chip(SDOC). The FPXC adopts the Self-Adaptive Process & Temperature Compensation Bandgap Reference Generator, the Gain-Boost Amplitude Control LC VCO and inverter type flash memory. The FPHA adopts the two-way flash switch and inverter type flash memory Look-Up-Table(LUT). The FPXC adopts the inverter type flash memory as the Non-Volatile Memory(NVM) to keep the setup data in the field frequency programming. The flash technology of FPHA and FPXC are compatible that the FPHA has the FPXC capability. The PLLess CDR(PLL free Clock Data Recovery) is based on the FPXC capability for the SerDes high frequency application. The PLLess CDR and pipeline ADC are for the analog front high frequency application. With the SDOC on FPHA, the Automobile Infotainment Center(MIC) is reduced to be Mobile Infotainment Center(MIC).

Abstract: A phase/frequency detector has a modulo counter for outputting a counter word with a predetermined word length depending on an oscillator signal. In addition, a modulo integrator for outputting an integrator word with the predetermined word length as a function of integration of a channel word is provided. The phase/frequency detector also has a difference element for outputting a phase error word with the predetermined word length as a function of a difference between the counter word and the integrator word.

Abstract: A correction processor connected to an oscillator uses precision timing signals propagated over a digital network to generate an error signal. IEEE-1588 time synchronization protocols produce precision time signals which are converted to precision interval signals. The correction processor uses the precision interval signals to count pulses of the oscillator. A correction circuit compares the counter output with a predetermined value and generates an error signal may be used to correct the oscillator or may be propagated to consumers of the oscillator. An arbitrary reference oscillator may be used to generate the precision timing signals propagated on the network, to slave other oscillators to it. The precision of the reference oscillator may be deliberately overstated to insure it is used as a master.

Abstract: Determination and processing for fractional-N programming values. The present invention is operable to receive a clock signal (CLK) and to transform that CLK into a new CLK, when necessary, for use by various circuitries within a system. The present invention is operable to generate two different CLKs for use by a radio frequency (RF) circuitry and a baseband processing circuitry in certain embodiments. The present invention employs a measurement circuitry and to characterize a first CLK and uses a fractional-N synthesizer to perform any necessary processing to generate the one or more CLKs to the other CLKs within the system. The first CLK may be received from an external source or it may be generated internally; in either case, the present invention is able to modify the CLK into another CLK for use by other circuitries within the system or for use by another external device.

Abstract: In one embodiment, the present invention includes an apparatus having a voltage controlled oscillator (VCO) to generate a first clock signal having a frequency controlled by a bias current coupling ratio of first and second bias currents, and a control circuit coupled to the VCO to generate a first pair of control signals to adjust the bias current coupling ratio. Other embodiments are described and claimed.

Abstract: Various systems and methods for implementing dynamic logic are disclosed herein. For example, some embodiments of the present invention provide LC tank circuits having an inductance and a capacitance. In addition, the circuits include a flicker noise reducing switch that is operable to selectively incorporate the capacitance such that an output of the circuit operates at a frequency based on a combination of the inductance and the capacitance.

Abstract: A PLL system for generating an output signal according to a first reference signal is disclosed. The PLL system includes a clock generator to generate the output signal according to a phase difference between the first reference signal and the frequency-divided signal; and a phase-shift detector for detecting a position difference between the physical address and an updated logical address of the recording data to generate a phase adjusting signal. The PLL system also includes an adder for updating a detected logical address with a random value to output the updated logical address to the position difference detector; and a phase-controllable frequency divider for generating the frequency-divided signal and for receiving the phase adjusting signal to adjust the phase of the frequency-divided signal.

Abstract: In an oscillating apparatus or a frequency detecting apparatus in which a center frequency and a variable frequency range are freely or optionally established with a high stability and a high accuracy, a first frequency component of a signal from a first crystal oscillator and a second frequency component of another signal from a second crystal oscillator are subjected to a synthesizing operation in a synthesizer and to other operations to obtain a desired center frequency and a desired variable frequency range.

Abstract: A microcomputer includes an oscillator for generating a clock signal having a frequency by using a CR circuit, a multiplier for outputting the clock signal having a multiplied frequency relative to the frequency generated by the oscillator based on data from an external source, a temperature detection unit for detecting temperature at a proximity of the CR circuit, a storage unit for storing data that enables the multiplied frequency of the clock signal in an output from the multiplier to have a constant value based on a temperature-dependent oscillation characteristic of the oscillator, and a control unit for setting a multiplication value for generating the multiplied frequency of the clock signal to the multiplier based on the data in the storage unit that is correlated to the temperature detected by the temperature detection unit.

Abstract: Phase-locked loop (PLL) logic comprises an oscillator that produces a first oscillator signal and phase detect logic that determines a phase difference between the first oscillator signal and a second oscillator signal. After the second oscillator signal is replaced by a third oscillator signal, the phase detect logic determines another phase difference between the first oscillator signal and the third oscillator signal. The PLL removes the phase difference from the another phase difference to produce an intermediate signal. The oscillator adjusts the first oscillator signal using the intermediate signal.

Abstract: A frequency synthesizer includes a phase-locked loop circuit having an output. A frequency divider is connected to the output of the phase-locked loop circuit for receiving the signal therefrom and dividing the frequency of the signal. A tunable bandpass filter is connected to the frequency divider and is tuned for selecting a harmonic frequency to obtain a fractional frequency division for a signal output from the phase-locked loop circuit.

Abstract: A multi-band VCO module includes a multi-band VCO and a controlling module. The multi-band VCO is for selecting a specific band from a plurality of bands according to a band selecting signal, and for outputting an oscillating signal according to a predetermined voltage and the specific band. The controlling module, coupled to the multi-band VCO, is for setting the band selecting signal according to a reference frequency of the reference signal and an oscillating frequency of the oscillating signal. A related method and a PLL circuit utilizing the multi-band VCO module are also disclosed.

Abstract: A fractional frequency synthesizer, applied to a phase-locked loop, includes a phase detector, a loop filter, a controllable oscillator, a first frequency divider, and a sigma-delta modulator (SDM). The phase detector generates a phase difference signal according to a reference signal and a feedback signal. The loop filter filters the phase difference signal to generate a filtered signal. The controllable oscillator generates the frequency signal according to the filtered signal. The first frequency divider generates the feedback signal by dividing a frequency of the frequency signal according to a dividing factor. The SDM determines the dividing factor according to a control signal.

Abstract: A low cost, low phase noise microwave synthesizer includes a DDS modulation circuit and a phase-locked loop. The DDS modulation circuit modulates the output of a DDS to a high frequency. The phase-locked loop downconverts the DDS output and locks the downconverted signal to a relatively low frequency, fixed reference.

Abstract: An apparatus, comprising: a first oscillator made from piezoelectric material to oscillate at a first frequency; a second oscillator to oscillate at a second frequency; a comparator to compare the first frequency to the second frequency; and a controller to change the first frequency in response to the comparing of the first frequency to the second frequency.

Abstract: A system and a method for operating the same. The system includes a fractional-N phase-locked loop (PLL). The PLL includes a PLL input and a PLL output. The fractional-N PLL further includes a multiplexer. The multiplexer includes a multiplexer output electrically coupled to the PLL input. The multiplexer further includes M multiplexer inputs, M being an integer greater than 1. Two or more reference frequencies are applied to the inputs of the multiplexer, by the selection of one from the reference frequencies, the low spur can be reached.

Abstract: A phase lock control system is presented for controlling a voltage controlled oscillator. The system includes a voltage controlled oscillator that produces a frequency signal exhibiting an output frequency that varies dependent upon the value of a control voltage applied thereto. A frequency deviation determining system employs a counter intermittently triggered ON for a fixed time by successive timing pulses received from a reference source and a comparator that determines any frequency deviation of the output frequency relative to a preset frequency. An error filter monitors the comparator for any frequency deviation for a plurality of samples of the frequency deviation determinations. A controller varies the control voltage to vary the output frequency in a direction to eliminate any frequency deviation.

Abstract: A method and enhanced phase-locked loop (PLL) circuit enable effective testing of the PLL. A phase frequency detector generates a differential signal, receiving a reference signal and a feedback signal of an output signal of the PLL circuit. A charge pump is coupled to the phase frequency detector receiving the differential signal. The charge pump applies either negative or positive charge pulses to a low-pass filter, which generates a tuning voltage input applied to a voltage controlled oscillator. A first divider is coupled to the voltage controlled oscillator receives and divides down the VCO output signal, providing the output signal of the PLL circuit. A second divider receives the output signal of the PLL circuit and provides the feedback signal to the phase frequency detector. The output signal of PLL circuit is applied to a clock distribution.

Abstract: A method for calibrating a phase locked loop begins by determining a gain offset of a voltage controlled oscillator of the phase locked loop. The processing then continues by adjusting current of a charge pump of the phase locked loop based on the gain offset.