Abstract: RFID tags, tag circuits, and methods are provided that reduce at least in part the distortion to received wireless signals, which is caused by interference in the environment. Two or more thresholds are used to digitize the received signal implemented by two or more demodulators. Multiple low pass and digital filters may be implemented with the demodulators, allowing removal of narrow pulses caused by the interference and reduction of beat tone amplitude.

Abstract: A digital phase-locked loop having a phase frequency detector (PFD), a 3-state phase frequency detection converter (3-state PFD converter), a loop filter and a digital voltage-controlled oscillator is provided. The PFD receives an input frequency and a reference frequency and outputs a first signal and a second signal based on the phase difference between the input frequency and the reference frequency. The 3-state PFD converter outputs a 3-state signal according to the first and second signals, wherein the 3-state signal is presented in 1, 0 and ?1. The loop filter outputs at least one control bit based on only the 3-state signal. The DCO adjusts the outputted oscillation frequency according to the control bit.

Abstract: There is provided an apparatus for the linearization of a digitally controlled oscillator. The apparatus includes a first filter outputting only a low frequency band signal of an input signal to the digitally controlled oscillator; a negative feedback loop causing the signal of an input port of the digitally controlled oscillator to pass through a frequency table and a frequency-to-digital code mapper in sequence and correcting an input of the digitally controlled oscillator by performing negative feedback to an input port of the first filter; and a frequency table generator storing a frequency value of an output signal of the digitally controlled oscillator in the frequency table.

Abstract: The A/D converter changes sampling timing of a received signal in a synchronization acquisition mode and a synchronization tracking mode. The A/D converter generates an internal clock of a sampling frequency eight times a symbol rate under the control of the clock control unit in the synchronization acquisition mode. On the other hand, in the synchronization tracking mode, the A/D converter generates an internal clock with a symbol point and one each point before and after the symbol point as sampling timing under the control of the clock control unit. The A/D converter further corrects the sampling timing of the symbol point based on the squares of the maximum value of a correlation value between the received signal and a reference signal and the absolute values of correlation values before and after the maximum value.

Abstract: A frequency synthesizer circuit that reduces undesired spurious sidebands while maintaining phase noise performance having a phase locked loop circuit comprising at least a phase detector, a controlled oscillator, a frequency divider coupled to the controlled oscillator for adjusting a frequency division of the frequency divider in response to a received control signal generated from a divisor value, a dithering circuit for providing a dither signal, and a sigma-delta modulator comprising an input for receiving a multi-bit input signal indicative of at least part of the divisor value. The input of the sigma-delta modulator is coupled with the dithering circuit for receiving the dither signal as a most significant bit of the multi-bit input signal.

Abstract: Phase and frequency detectors and techniques are disclosed. For example, apparatus comprises a first circuit for receiving first and second clock signals and for generating at least one signal indicative of a phase difference between the first and second clock signals. The apparatus also comprises a second circuit for receiving the at least one signal generated by the first circuit and, in response to the at least one received signal, generating at least one output signal, wherein a frequency associated with the at least one output signal is proportional to a frequency difference between the first and second clock signals.

Abstract: A phase locked loop (PLL) is provided. In one implementation, the PLL includes a multiphase voltage controlled oscillator (VCO) operable to generate an output signal containing one or more phase signals, a programmable divider operable to divide a frequency of the output signal of the multiphase VCO to produce a divided frequency output signal, and a fractional divider to fractionally divide an input phase signal. The fractional divider can include an integer divider operable to receive the input phase signal and divide the input phase signal in accordance with an integer divisor to produce a divided signal as an input to the multiphase VCO, and a phase interpolator operable to select a phase signal from among the one or more phase signals output by the multiphase VCO, to produce an interpolated output signal having a desired frequency resolution.

Abstract: A discrete-time phase lock loop (DTPLL) includes an analog section comprising a digital-to-analog converter (DAC) and an oscillator, operative to provide a clock signal based on an input from the DAC. The DTPLL also includes a digital signal processor (DSP). The DSP includes a loop controller state machine; a phase detector; a counter, operative to receive clock signals from the oscillator and to provide a count value to the phase detector; a divider, operative to receive a reference signal and to provide a reference pulse output to the phase detector; and a loop filter operative to provide a control effort value based on an output from the phase detector. Based on the phase error value, an output of the oscillator is changed to reduce the phase error to a steady state value.

Abstract: A semiconductor chip area is reduced and the possibility of malfunction in generation of reproduction data and a reproduction clock is reduced. A transceiver comprises a clock data recovery circuit, a deserializer, a serializer, a PLL circuit, and a frequency detector. The clock data recovery circuit extracts a reproduction clock and reproduction data in response to a receive signal and a clock signal generated by the PLL circuit. The deserializer generates parallel receive data from the reproduction clock and the reproduction data, and the serializer generates a serial transmit signal from parallel transmit data and the clock signal. The detector detects a difference in frequency of the receive signal and the clock signal, and generates a frequency control signal. In response to the frequency control signal, the PLL circuit controls a cycle of the clock signal so as to reduce the difference in frequency.

Abstract: An update control apparatus in a DLL circuit is provided. The update control apparatus includes a logic value determination, a phase information collection unit, and an update control unit. The logic value determination unit is configured to determine a logic value of a phase detection signal for a first period interval of a reference clock signal to generate a phase information signal, and configured to extend the first period interval into a second period interval when an extension instruction signal is enabled. The phase information collection unit is configured to determine consecutive logic values of an update possible signal to generate the extension instruction signal, and configured to collect the phase information signal to generate an update information signal. The update control unit is configured to generate the update possible signal, a valid interval signal, and an update control signal in response to the update information signal.

Abstract: A delay synchronization loop type clock signal generating circuit includes: a digital delay line for delaying a first clock signal and generating a second clock signal; a ring-type shift register for setting the delay time length of the digital delay line by flip-flop output of each stage thereof; and a delay amount control unit for controlling supply of shift clocks to the ring-type shift register, based on phase relation between the first clock signal and the second clock signal.

Abstract: A voltage controlled oscillator 1, a variable frequency divider 2, a phase comparator 3, and a loop filter 4 form a Phase Locked Loop (PLL). A sigma-delta modulator 5 sigma-delta modulates data obtained by adding a fractional part M2 of the frequency division factor data with modulation data X by using an output signal of the variable frequency divider 2 as a clock. An output signal of the sigma-delta modulator 5 is added to an integral part M1 of the frequency division factor data, and the resultant data becomes effective frequency division factor data 13 of the variable frequency divider 2. An output signal of the sigma-delta modulator 5 also becomes control data 14 after passing through a D/A converter 6, a low-pass filter 7, and an amplitude adjustment circuit 8. The control data 14 is inputted into a frequency modulation terminal of the voltage controlled oscillator 1.

Abstract: A phase-locked loop (PLL) circuit includes a reference clock divider with a reference clock input, a phase-frequency detector, a charge pump, a loop filter, a voltage controlled oscillator and a feedback divider. A method of operating the PLL circuit comprises the steps of detecting a failure of a reference clock applied to the reference clock input, disabling the charge pump upon detection of a reference clock failure, monitoring the reference clock to detect restoration of a regular reference clock, upon detection of a regular reference clock, detecting occurrence of the next pulse from the feedback divider, and enabling the charge pump upon detection of the next pulse from the feedback divider.

Abstract: A technique to mitigate noise spikes in an electronic circuit device such as an integrated circuit. The clock frequency of a clock signal used by the electronic circuit is controlled such that instantaneously large changes to the clock frequency are avoided by use of a frequency filter that is capable of generating frequency ramps having a linear slope which is used as a feedback signal in a digital phase-locked loop clock circuit in lieu of a discrete, stair-stepped feedback control signal.

Abstract: A digital phase-locked loop and a digital phase-frequency detector thereof are provided. The digital PFD includes a divisor switch unit, a low-resolution phase-error detecting unit, an accumulating unit, a high-resolution phase-error detecting unit, a constant unit, and a selector. The divisor switch unit receives and removes partial pulses of a feedback signal for obtaining a feedback clock. The low-resolution phase-error detecting unit detects phase error between a reference signal and the feedback clock to obtain a phase-error pulse width. The accumulating unit accumulates the feedback signal during the phase-error pulse width for obtaining an output selection signal. The high-resolution phase-error detecting unit detects phase error between the reference signal and the feedback signal to obtain a phase-error value. The constant unit provides at least one constant value. The selector selects and outputs one of the phase-error value and the constant value according to the output selection signal.

Abstract: One delay locked loop circuit embodiment includes a delay line system configured to generate a clock output signal by adding a delay line system time delay to a clock reference signal, a phase detector, a shift register, and a control unit. The delay line system includes a coarse delay line to adjust the delay line system time delay by remote coarse-shifting, a phase selector configured to adjust the delay line system time delay by local coarse-shifting output signals from a series of local coarse delay units, and a phase mixer to adjust a particular time delay of the clock output signal by fine-shifting. The phase mixer does not receive the clock reference signal. The phase detector detects a phase difference between the clock reference signal and the clock output signal. The shift register controls the remote coarse-shifting, and the control unit controls the local coarse-shifting, based on the phase difference.

Abstract: Disclosed herein are techniques, systems, and methods relating to compensation of phase disturbances of a phase lock-loop during power ramp up or down of a power amplifier. More specifically, a phase lock-loop is described that is able to switch between type I and type II PLL modes depending on the power state of the power amplifier without introducing additional disturbances.

Abstract: A method and apparatus are disclosed for generating phase controlled data, based on a roaming tap interpolator. The present invention recognizes that roaming tap interpolators have inherent nonlinearities and discontinuities at the boundaries of each interpolation region. A roaming tap interpolator is disclosed that shifts the interpolation curve in time in order to avoid the undesired artifacts in the interpolation curve. A roaming tap interpolator generally comprises a plurality of delay elements that delays a first signal to generate a plurality of interpolation regions each having an associated phase; a multiplexer to select one or more of the interpolation regions; and an interpolator to process the selected one or more of the interpolation regions to generate a second signal.

Abstract: The disclosure provides systems and methods for programmable fixed frequency digitally controlled oscillators for multirate low jitter frequency synthesis. The present invention utilizes a digital control element, such as a complex programmable logic device (CPLD) or field programmable gate array (FPGA), to monitor the frequency offset of a DCO with respect to one or more timing module (TM) references. The frequency offset is measured by aligning the phase of a DCO feedback divider to the phase of a reference divider, and then counting the number of pulses in the DCO between the falling edges of the feedback to determine a frequency error. Falling edge detection is used to determine a sign of the error. The digital control element then calculates a frequency correction based on a linear scaling factor to send a new control word to the DCO to reduce the frequency error.

Abstract: A receiver device implements enhanced data reception with edge-based clock and data recovery such as with a flash analog-to-digital converter architecture. In an example embodiment, the device implements a first phase adjustment control loop, with for example, a bang-bang phase detector, that detects data transitions for adjusting sampling at an optimal edge time with an edge sampler by adjusting a phase of an edge clock of the sampler. This loop may further adjust sampling in received data intervals for optimal data reception by adjusting the phase of a data clock of a data sampler such a flash ADC. The device may also implement a second phase adjustment control loop with, for example, a baud-rate phase detector, that detects data intervals for further adjusting sampling at an optimal data time with the data sampler.

Abstract: A phase locked loop circuit in accordance with an embodiment implements a digital phase delay quantizer to replace the analog charge-pump and phase frequency detector in an analog PLL circuit. Therefore, the built-in loop filter can be a compact-sized, high order, high bandwidth, and high attenuation digital filter as well. The digital PLL circuit takes advantage of the deep sub-micron process technology which features high speed, high resolution, compact size, and low power.

Abstract: A methodology is disclosed that enables the delay stages of an analog delay locked loop (DLL) or phase locked loop (PLL) to be programmed according to the operating condition, which may depend on the frequency of the input reference clock. The resulting optimized delay stages allow for a broad frequency range of operation, fast locking time over a wide range of input clock frequencies, and a lower current consumption at high clock frequencies. Better performance is achieved by allowing the number of analog delay stages active during a given operation to be flexibly set. The deactivation or turning off of unused delay stages conserves power at higher frequencies. The high frequency range of operation is increased by using a flexible number of delay stages for various input clock frequencies. Because of the rules governing abstracts, this abstract should not be used to construe the claims.

Abstract: A digital phase-locked loop (DPLL) supporting two-point modulation is described. In one design, the DPLL includes a phase-to-digital converter and a loop filter operating in a loop, a first processing unit for a lowpass modulation path, and a second processing unit for a highpass modulation path. The first processing unit receives an input modulating signal and provides a first modulating signal to a first point inside the loop after the phase-to-digital converter and prior to the loop filter. The second processing unit receives the input modulating signal and provides a second modulating signal to a second point inside the loop after the loop filter. The first processing unit may include an accumulator that accumulates the input modulating signal to convert frequency to phase. The second processing unit may include a scaling unit that scales the input modulating signal with a variable gain.

Abstract: A signal processing circuit includes a feedback control loop that includes a loop filter and that detects the difference between a target value and a control value to control the difference so that the difference has a predetermined value. A closed loop formed in the feedback control loop is expressed by the delay of the entire closed loop serving as the feedback control loop, the loop filter, and simple integration of a final stage. The signal processing circuit includes a moving average calculating unit configured to calculate a moving average of outputs from the loop filter; a multiplying unit configured to multiply a value calculated in the loop filter by a certain gain; and an integrating unit provided upstream of the loop filter so that calculation results by the moving average calculating unit and the multiplication unit are concurrently fed back to an input into the loop filter.

Abstract: A system and method for performing output clock phase smoothing. A phase smoothing circuit is described and includes a numerically-controlled oscillator (NCO) configured to produce a plurality of NCO clock pulses at a selectable frequency that is based on an input clock. Edges of the plurality of NCO clock pulses are aligned to edges of the input clock. A phase error calculation module is coupled to the NCO and is configured to generate a corresponding phase error for each of the plurality of NCO clock pulses. A clock phase selectable delay is coupled to the phase error calculation module and is configured to adjust each of the plurality of NCO clock pulses according to the corresponding phase error to generate an output clock at the selectable frequency that are phase-adjusted to more closely match an ideal output clock phase. Edges of the output clock need not necessarily align to the edges of the input clock.

Abstract: A method for fast tracking and jitter improvement in an asynchronous sample rate conversion includes a digital phase locked loop (DPLL) for an asynchronous sample rate conversion (ASRC) device. A control apparatus in the DPLL includes a gain controller that sets and maintains gains (Ki, Kp) of two branches of the control apparatus at a fixed value, which enables searching of a desired value by the DPLL to determine a neighborhood of the desired value, and reduces the gains when the number of samples reaches a predetermined number. Processing units in the DPLL generate and process first and second input signals based on an input clock, an output clock, and a system clock. The second input signal is processed using two branches. Signals resulting from the two branches are re-aligned according to a changed status of the first processed input signal such that the signals resulting from the two branches are sampled in the same input clock interval.

Abstract: A novel and useful apparatus for and method of local oscillator (LO) generation with non-integer multiplication ratio between the local oscillator and RF frequencies. The LO generation schemes presented are operative to generate I and Q square waves at a designated frequency while avoiding the well known issue of harmonic pulling. An input baseband signal is interpolated and upconverted in the digital domain to an IF. The LO operates at a frequency which is a n/m division of the target RF frequency fRF. The IF frequency is configured to ½ of the LO frequency. The upconverted IF signal is then converted to the analog domain via digital power amplifiers followed by voltage combiners. The output of the combiners is band pass filtered to extract the desired replica.

Abstract: A Phase Locked Loop (1) used in a data and clock recovery comprising a frequency detector (10) including a quadricorrelator (2), the quadricorrelator (2) comprising a frequency detector including double edge clocked bi-stable circuits (21, 22, 23, 24) coupled to a first multiplexer (31) and to a second multiplexer (32) being controlled by a signal having a same bitrate as the incoming signal (D), and a phase detector (DFF) controlled by a first signal pair (PQ, PQ provided by the first multiplexer (31) and by a second signal pair (PI, PI) provided by the second multiplexer (32).

Abstract: A detection arrangement includes a counter unit which receives a first clock signal and a reference clock signal. The counter unit derives a first data word as a function of a time deviation between clock edges of the first clock signal and the reference clock signal. The detection arrangement further includes a signal processing unit to determine a phase deviation word as a function of the first data word and a second data word, the second data word based on the duration of a clock period of the reference clock signal.

Abstract: A novel and useful apparatus for and method of local oscillator (LO) generation with non-integer multiplication ratio between the local oscillator and RF frequencies. The LO generation schemes presented are operative to generate I and Q square waves at a designated frequency while avoiding the well known issue of harmonic pulling. The signal is input to a synthesizer timed to a rational multiplier of the RF frequency fRF. The signal is then divided to generate a plurality of phases of the divided signal. A plurality of combination signals are generated which are then multiplied by a set of weights and summed to cancel out some undersired products. The result is filtered to generate the LO output signal.

Abstract: A method and an improved apparatus for clock recovery from data streams containing embedded reference clock values controlled clock source includes of a controllable digital fractional divider receiving a control value from digital comparator and a clock input from a digital clock synthesizer driven by a fixed oscillator.

Abstract: The present invention provides a PLL circuit containing a loop gain circuit capable of suppressing loop gain variation. This PLL circuit includes a counter that is driven by a voltage controlled oscillator within the PLL circuit, an accumulator (ACL) that accumulates the output of the counter, and a comparison operation circuit block that compares the count value of the ACL and the design value pre-stored in a register, and the loop gain of the PLL circuit is detected taking advantage of the fact that the ACL count value is inversely proportional to the loop gain. Based on the detection result, the loop gain is calibrated by correcting the loop gain with a charge pump current, etc. This allows the PLL circuit to maintain stable loop characteristics that will not affect the characteristics variation of each element constituting the PLL.

Abstract: A novel mechanism that is operative to observe and compare the differentiated phase of the reference and variable PLL loop signals using a frequency detector. The resultant phase differentiated error is then accumulated to yield the phase error. The operation of the loop with the frequency detector is mathematically equivalent to that of the phase detector. A frequency error accumulator is used to generate the integral of the frequency error. The frequency error accumulator also enables stopping the accumulation of the frequency upon detection of a sufficiently large perturbation, effectively freezing the operation of the loop as subsequent frequency error updates are not accumulated. Upon removal of the phase freeze event, accumulation of the frequency error and consequently normal loop operation resumes.

Abstract: Systems and methods for design and operation of signal generator circuitry with output frequencies greater than the oscillator frequency. Accordingly, in a first method embodiment, a method of producing an output periodic electronic signal comprises accessing four signals having a quadrature phase relationship. First and second pairs of these signals having a one half cycle phase relationship are averaged to produce two signals having an improved duty cycle and a one-quarter cycle phase relationship. The first and second averaged periodic electronic signals are combined in an exclusive OR circuit to produce the output periodic electronic signal at twice the oscillator frequency. Advantageously, the periodic signal may comprise a desirable duty cycle of 50 percent.

Abstract: A spread spectrum clock generating apparatus is disclosed. The spread spectrum clock generating apparatus includes a phase lock loop module and a spread spectrum module. The phase lock loop module is used for dynamically tuning frequency of an output clock. The spread spectrum module includes a counter, a plurality of delta-sigma counters and a data shifter. These delta-sigma counters accumulate input signals, and enable a first overflow signal while accumulation of a last stage delta-sigma counter is overflowed. The frequency of the output clock can be tuned dynamically according to the first overflow signal, and the spectrum of the output clock can be spread.

Abstract: Methods and apparatus are provided for improving the performance of second order CDR systems. The integral state of the CDR system is initialized to a value that is based on an expected frequency profile that may be known a priori for certain applications. One or more quality of lock (QOL) metrics are also monitored that are derived from the integral register state value. A quality of a locking between a received signal and a local clock generated by a Clock and Data Recovery (CDR) system is evaluated by monitoring a state value of an integral register in a digital loop filter of the CDR system; evaluating one or more predefined criteria based on the integral register state value; and identifying a poor lock condition if the one or more predefined criteria are not satisfied.

Abstract: A signal processing apparatus of an electronic device not only cuts off supply of power to a hardware unit from a power supply unit when a control signal associated with a power OFF command is supplied from an instruction input unit, but also turns OFF a switching circuit of an oscillation circuit unit, thereby cutting off supply of power to the oscillation circuit unit. The switching circuit is configured to be turned ON according to input of a signal from an interrupt port unit, and resumes supply of the power to the oscillation circuit unit upon supply of a control signal from the instruction input unit. When supply of a clock signal to a CPU circuit unit from the oscillation circuit unit is resumed, the CPU circuit unit resumes supply of power to the hardware unit from the power supply unit after operation of the CPU circuit unit is stabilized.

Abstract: In one aspect, the invention comprises a system comprising: a master data clock source; one or more transponders; and a plurality of remote power line transceivers; wherein all of said plurality of transceivers are connected to a common alternating current power distribution grid; and wherein each of said plurality of transceivers has a location is operable to monitor a voltage waveform of a power line prevailing at said location. In another aspect, the invention comprises a system comprising: transponders and remote power line transceivers each connected to a common alternating current power distribution grid each operable to monitor the voltage waveform of the power line prevailing at its own location, and generate selectable frequencies from said local power line waveform of a frequency of p/q times the frequency of said power line where p and q are positive integers greater than or equal to 1.

Abstract: A novel and useful apparatus for and method of local oscillator (LO) generation with non-integer multiplication ratio between the local oscillator and RF frequencies. The LO generation schemes presented are operative to generate I and Q square waves at a designated frequency while avoiding the well known issue of harmonic pulling. The use of analog mixers of the prior art is avoided and replaced with an XOR gate configured to generate the correct average frequency. The edges are dynamically adjusted by ±T/12 or zero based on the state of the controlled oscillator down-divided clock.

Abstract: PLL (phase locked loop) circuits and methods are provided in which PWM (pulse width modulation) techniques are to achieve continuous fine tuning control of DCO (digitally controlled oscillator) circuits. In general, pulse width modulation techniques are applied to further modulate dithered control signals that are used to enhance the frequency tuning resolution of the DCO such that the dithered control signals are applied to the fractional tracking control port of the DCO for a selected fraction of a full clock signal based pulse width modulation applied.

Abstract: A temperature sensing circuit using a delay locked loop and a temperature sensing method. The temperature sensing circuit includes a locked delay unit for receiving an external clock and generating a locked delay pulse keeping a constant delay amount regardless of temperature. A variable delay unit may have a chain structure of a plurality of delay cells depending upon temperature. The variable delay unit may receive the external clock and generate variable delay pulses having respectively different delay amounts based on temperature. A decision control unit is configured to sense a determination temperature by using a phase difference between one selected from the variable delay pulses and the locked delay pulse. Accordingly, an unnecessary time and cost causable by temperature compensation can be reduced, and an automatic temperature compensation and a precise temperature sensing operation can be obtained.

Abstract: A phase locked loop circuit which obtains an output signal coincident in frequency and phase with a target signal which is acquired by multiplying the frequency of a reference signal by a ratio represented by the sum of a first fraction and a second fraction, the circuit includes a controlled oscillator including the same number of stages of annularly connected amplifiers as a number which is obtained by dividing, by 2, a least common multiple of a denominator of the first fraction, a denominator of the second fraction and 2, the same number of multiphase signals as the least common multiple being extractable from the controlled oscillator, the frequency of the multiphase signals being controlled by a digital control signal and an analog control signal, one of the multiphase signals being output as the output signal.

Abstract: In one embodiment, a phase error signal generated by a phase detector is equalized to compensate for the distortion in the phase error signal due to finite circuit speeds. The equalization may be based on suppressing the low frequency components of the phase error signal. For example, the amplitude of the phase error signal may be reduced when the amplitude of the phase error signal is not changing.

Abstract: A PLL comprises a PFD, a loop filter and a VCO, as well as a voltage shift capacitor coupling the PFD and the VCO. A voltage shift control circuit is placed in parallel with the voltage shift capacitor. This circuit comprises controlled charging means, which are designed to charge the voltage shift capacitor according to a channel control signal. It also comprises controlled pre-charging means which are designed to accelerate the charging of the voltage shift capacitor by the controlled charging means. It further comprises controlled biasing means, designed to ensure the bias of the input during the pre-charging of the voltage shift capacitor.

Abstract: A phase controller device according to the invention comprises a hardware core that is formed by a signal detector, a voltage-controlled oscillator, a phase comparator, and an integration unit, where the hardware core, by controlling the working clock pulse frequency of the microcontroller, brings an output clock pulse signal that is generated by a microcontroller into phase with the input clock pulse information that is received from the input data stream, and does so in such a manner that the jitter is low. The microcontroller executes a program with this working clock pulse, where with that program the microcontroller generates the output clock pulse signal with an output clock pulse frequency that is in a predetermined division ratio to the control clock pulse frequency that is generated by the voltage-controlled oscillator and is given to the microcontroller as a working clock pulse frequency.

Abstract: A digital phase-locked loop circuit includes: a first counter which counts a first clock; a second counter which counts third clocks into which a second clock is divided; a first phase detector which detects a relative phase difference between the first and the third clocks according to a first comparison result that clocks in which the third clock is delayed are compared with the first clock and a second comparison result that clocks in which the first clock is delayed are compared with the third clock; a second phase detector which measures the period of the second clock; a phase error calculating unit which calculates a phase difference between the first and the third clocks according to the value that the result detected by the first phase detector is normalized by the result detected by the second phase detector and the count values of the first and the second counters; and a DCO which outputs the second clock according to the result calculated by the phase error calculating unit.

Abstract: Techniques for converting an accumulated phase of a signal into a digital value in a digital phase-locked loop (DPLL). In an exemplary embodiment, a signal is coupled to a divide-by-N module that divides the frequency of the signal down by a divider ratio N. The divided signal is input to a delta phase-to-digital converter, which measures the phase difference between a rising edge of the divided signal and a rising edge of a reference signal. The accumulated divider ratios and the measured phase differences are combined to give an accumulated digital phase. Further techniques for varying the divider ratio N using a sigma-to-delta modulator are disclosed.

Abstract: An apparatus for setting an operation mode in a DLL circuit generates a locking completion signal according to a level of a phase comparing signal obtained by comparing phases of a reference clock and a feedback clock. During three or more cycles of a pulse signal, it is determined whether a logic value of levels of the phase comparing signal is a specific combination, and the locking completion signal is selectively enabled.

Abstract: In a radiation detector (10) for a time of flight positron emission tomography (PET) scanner (2), a radiation sensitive member (20) generates a signal (22) indicative of a radiation detection event. A time to digital converter (34) includes digital delay elements (40) operatively interconnected as a ring oscillator (36, 36?) and readout circuitry (50, 52, 60, 82, 84, 86, 88) configured to generate a timestamp for the radiation detection event based at least on a state of the ring oscillator when the signal is generated. Delay trim elements (46) operatively connected to the digital delay elements set a substantially common delay for the digital delay elements.

Abstract: Method and apparatus for performing joint timing recovery in a digital receiver using multiple input signals. The apparatus comprises a plurality of phase detectors, a summer, a level shifter, a loop filter and a numerically controlled oscillator NCO. The phase detectors produce a phase signal by comparing a timing signal produced by the NCO with the input signals. The phase signals are then summed and the level shifter adjusts the summed value to compensate for the number of signals used to form the sum, i.e., the summed value is adjusted to be within the input range of the NCO.