Abstract: This invention discloses a phase interpolation controller for a clock and data recovery circuit receiving an indication of a phase relationship between a first and a second signal, the phase interpolation controller comprises a plurality of serially coupled bi-directional shift-registers, wherein when the received indication indicates the first signal is ahead of the second signal in phase, the plurality of serially coupled bi-directional shift-registers shifts in one of the bi-directions, and when the received indication indicates the first signal is behind the second signal in phase, the plurality of serially coupled bi-directional shift-registers shifts in the other of the bi-directions.

Abstract: A method may include performing a logical exclusive OR and a logical inverse exclusive or on an input reference signal and an output signal to generate an XOR signal and an XNOR signal, respectively. The method may also include generating a switch control signal indicative of whether a first phase of the input reference signal leads or lags a second phase of the output signal. The method may additionally include: (i) transmitting the XOR signal to an output of a switch if the first phase leads the second phase; and (ii) transmitting the XNOR signal to the output of the switch if the first phase lags the second phase. The method may further include generating a phase detector output signal indicative of a phase difference between the second phase based on a signal present on the output of the switch.

Abstract: For reconstructing a data clock from asynchronously transmitted data packets, a control loop is provided which includes a controlled oscillator. An input signal of the control loop is generated on the basis of the received data packets. At least one high-pass type filter is provided in a signal path of the control loop. The data clock for the synchronous output of data is generated on the basis of an output signal of the controlled oscillator.

Abstract: Arbitrary phase variations of a shared frequency synthesizer can be calibrated using a reference harmonic each time the shared frequency synthesizer is allocated to a network device to enable one frequency synthesizer to be shared between multiple network devices. On determining that the shared frequency synthesizer has been allocated to the network device, an output frequency of the shared frequency synthesizer can be aligned with a predetermined reference frequency that is associated with an operating frequency band of the network device. A phase correction factor associated with the shared frequency synthesizer can be calculated from a signal calculated based, at least in part, on the output frequency of the shared frequency synthesizer and the predetermined reference frequency. The phase correction factor is applied to a signal received at the network device to correct a phase error associated with the shared frequency synthesizer.

Abstract: A memory controller receives data and phase-providing signals from a memory device. The phase-providing signal is not a clock signal, but is used by the memory controller to phase align a local data-sampling signal with the incoming data. The memory controller samples the data signal with the data-sampling signal. The memory controller can perform maintenance operations to update the phase relationship between the phase-providing and data-sampling signals.

Abstract: A system and method is provided for phase interpolator based transmission clock control. The system includes a transmitter having a phase interpolator coupled to a master timing generator and a transmission module. The phase interpolator is also coupled to a receiver interpolator control module and/or an external interpolator control module. When the system is operating in repeat mode, the transmitter phase interpolator receives a control signal from a receiver interpolator control module. The transmitter phase interpolator uses the signal to synchronize the transmission clock to the sampling clock. When the system is operating in test mode, a user defines a transmission data profile in an external interpolator control module. The external interpolator control module generates a control signal based on the profile. The transmitter phase interpolator uses the signal to generate a transmission clock that is used by the transmission module to generate a data stream having the desired profile.

Abstract: A system and method for signal mismatch compensation in a wireless receiver is disclosed. The method includes receiving an in-phase (I) signal and a quadrature (Q) signal corresponding to the I signal, the Q signal having an ideal phase offset of 90 degrees from the I signal, where there is a phase and gain mismatch between the I signal and Q signal. The method adjusts the phase offset between the I signal and the Q signal to minimize the IQ power, where the IQ power is the average-time power of a digital baseband in-phase (DB-I) signal and a digital baseband quadrature (DB-Q) signal, corresponding to the I signal and Q signal, respectively. The method adjusts the gain of the Q signal to minimize the IQ power, whereby the phase and gain mismatch between the I signal and Q signal is minimized.

Abstract: An all digital phase-locked loop (ADPLL) includes: a phase counter accumulating a frequency setting word value and the phase of a digitally controlled oscillator (DCO) clock and detecting a fine phase difference between a reference clock and a retimed clock; a phase detector detecting a digital phase error value compensating for a phase difference between the frequency setting word value and the DCO clock according to the fine phase difference to detect a digital phase error value; a digital loop filter filtering the digital phase error value and controlling PLL operational characteristics; a lock detector generating a lock indication signal according an output of the digital loop filter; a digitally controlled oscillator varying the frequency of the DCO clock according to the output from the digital loop filter; and a retimed clock generator generating the retimed clock by retiming the DCO clock at a low frequency.

Abstract: A method of achieving reduced modulation range requirement in a Digitally Controlled Oscillator (DCO) which is deployed as part of a DRP (Digital Radio Processor) and tuned to a tuning frequency range having operating-channel center-frequencies, wherein phase difference between consecutive samples is termed as FCW (Frequency Control Word), uses the steps of digitally modifying and limiting the FCW so that the FCW does not exceed known FCW thresholds, e.g., chosen from ?/2, ?/4, ?/8, and redistributing the FCWs while maintaining a cumulative sum of phases and without significant EVM (Error Vector Magnitude) degradation. The FCW threshold can be chosen arbitrarily and need not be in the form of ?/2n. The method uses a FCW limiting algorithm which reduces supply voltage sensitivity of the DCO and enables significant reduction in area of capacitor bank which would be otherwise needed.

Abstract: A phase locked loop (PLL) device is configurable in an analog phase locked loop and a hybrid analog-digital phase locked loop. In an analog mode, at least a phase detector, an analog loop filter, and a voltage controlled oscillator (VCO), are connected to form an analog loop. In a digital mode, at least the phase detector, the voltage controlled oscillator (VCO), a time to digital converter (TDC), a digital loop filter and a digital to analog converter (DAC) are connected to form the hybrid digital-analog loop.

Abstract: The present invention relates to a phase recovery device, phase recovery method and receiver for 16 QAM data modulation.

Abstract: A frequency detector includes an error measurement unit measuring a time interval between zero-crossing points of an input signal that is modulated. An error conversion unit quantizes the measured time interval using one of modulation time intervals. An error calculation unit calculates a frequency error based upon a difference between the measured time interval and the quantized time interval. An error generation control unit controls whether to output the frequency error based upon the quantized time interval, the calculated frequency error, and a predetermined critical value.

Abstract: A circuit for performing clock recovery according to a received digital signal (30). The circuit includes at least an edge sampler (105) and a data sampler (145) for sampling the digital signal, and a clock signal supply circuit. The clock signal supply circuit provides edge clock (25) and data clock (20) signals offset in phase from one another to the respective clock inputs of the edge sampler (105) and the data sampler (145). The clock signal supply circuit is operable to selectively vary a phase offset between the edge and data clock signals.

Abstract: A phase calibration circuit applied to at least one signal processing module group includes at least two phase calibration modules, a phase detection module and a filter module. An output node of a first phase calibration module is coupled to an input node of a first signal processing module, an input node of a second phase calibration module is coupled to an output node of the first signal processing module, and the first signal processing module receives a calibrated signal outputted from the first phase calibration module and generates a processed signal. The phase detection module is utilized for generating a phase error signal according to a calibrated signal of an Mth phase calibration module, where M is an integer equal to or greater than two. The filter module is utilized for generating at least a first and a second phase calibration signal according to the phase error signal.

Abstract: An acquisition module includes a coherent correlator configured to receive a transmission having a pilot signal and correlate the received transmission with a local copy of the pilot signal to produce a first output, a delayed correlator configured to delay the first output and correlate the first output with the delayed first output to produce a second output, and a detector configured to detect the pilot signal in the transmission based on the second output.

Abstract: Embodiments of the present invention relate to a system for clock synthesis or data timing recovery. No analog continuous time oscillator is required, all the building blocks of a Frequency Locked Loop/Phase Locked Loop belonging in the digital discrete time domain. From a system-level perspective, the system is characterized by its strong non-linear behavior due to the intrinsic nature of some building blocks. This inherent non-linearity is responsible for some unusual, attractive property of the complete system. The system is able to multiply the input frequency clock by an arbitrarily large factor, ensuring in any case the convergence of the algorithm in two reference clock cycles.

Abstract: The present invention describes methods and circuitry for a sub-rate bang-bang phase detector, in which the reference clock has frequency that is a fraction of the bit rate of the received data stream. The sub-rate bang-bang phase detector is enabled by multiple phases of the reference clock.

Abstract: A system and method for performing clock and data recovery. The system sets the phase of a recovered clock signal 30 according to at least three estimates of the rate of change of an offset between the frequency of the data transmitter clock and the frequency of a receiver clock 15.

Abstract: An automatic frequency monitoring circuit automatically monitors a frequency of a clock related to an operation of a device to be monitored. In the automatic frequency monitoring circuit, a frequency detecting unit detects, upon detecting a predetermined momentum, the frequencies of a monitoring target clock during a predetermined time for a predetermined number of times and treats as a detection frequency of the monitoring target clock, an average of the frequencies that are detected for the predetermined number of times. A frequency monitoring unit monitors, upon the frequency detecting unit detecting the detection frequency of the monitoring target clock, whether the frequency of the monitoring target clock during the predetermined time is within a predetermined fluctuation range based on the detection frequency.

Abstract: A signal recovery circuit capable of expanding the receive margin is provided. The signal recovery circuit comprises for example a clock generator unit CLK_GEN for generating the clock signals CLKa, CLKb, and CLKc, a window width control unit WW_CTL, and a clock data discriminator unit CD_JGE for generating a phase detector signal (EARLY, LATE) when for example a data signal Di pulse edge enters between the CLKa and CLKb, or between the CLKb and CLKc, and the clock generator unit. Along with exerting control based on these phase detection signals to maintain the mutual phase differential of the overall phase of CLKa, CLKb, CLKc so as to prevent intrusion of the above described Di edge, the CLK_GEN also regulates the phase differential between CLKa and CLKb, and the phase differential between CLKb and CLKc based on a signal (Sww) from the WW_CTL.

Abstract: A clock regeneration circuit according to the present invention that generates a clock signal that is synchronized to an input signal, includes: a detection section which detects points at which the input signal transitions; a histogram generation section which associates a plurality of partial periods with the transition points, and generates a first histogram indicating an incidence of the transition points for each of the partial periods, the partial periods being generated by dividing a reference period of the clock signal; a calculation processing section which generates a second histogram by calculation processing based on the first histogram, and calculates a phase adjustment value of the clock signal based on the second histogram; and a phase adjustment section which adjusts a phase of the clock signal based on the phase adjustment value.

Abstract: System and method for improving a digital PLL's performance by making fine grained adjustments to the loop gain. A preferred embodiment comprises a plurality of loop gain adjustors (such as loop gain adjustors 605, 606, 607, and 608) that can incrementally adjust the loop gain. The incrementally adjusted loop gains are sequentially brought on-line so that the loop gain of the digital PLL is slowly decreased. By slowly decreasing the loop gain, the digital PLL is less perturbed by smaller noise transients that would take time to settle. Hence, the digital PLL can quickly acquire a signal and then decrease its loop gain and hence its bandwidth when it only needs to track a signal. The reduced bandwidth also reduces the overall noise in the digital PLL that is due to the reference noise contribution.

Abstract: The present invention provides a method and apparatus for initiating a multiple input multiple output (MIMO) communication. The method and apparatus includes processing that begins by transmitting a frame formatted in accordance with a default MIMO active transmitter-receiver antenna configuration to a target receiver. The processing continues by receiving at least one response frame from the target receiver. The processing continues by determining a number of receiver antennas of the target receiver from the at least one response frame.

Abstract: Methods and apparatuses for reducing noise in frequency to digital converters (FDCs). An FDC apparatus includes a first FDC, a second FDC and a combiner. The first and second FDCs are configured to independently sample an input signal according to a sample clock to generate first and second digital signals, each representing the instantaneous frequency of the input signal. The combiner is configured to form a resultant digital signal from the first and second digital signals. The first and second FDCs are designed and combined in the noise-canceling FDC apparatus so that the first and second signals they generate have correlated noise profiles in a frequency range of interest. When combined by the combiner to form the resultant digital signal, the resultant digital signal has a signal power to noise power ratio greater than the signal power to noise power ratios characterizing the first and second digital signals of the individual first and second FDCs.

Abstract: A clock data recovery circuit that supplies stable reference clocks to the object respectively by shortening the time of bit synchronization with each received burst data signal regardless of jittering components included in the received burst data signal, includes an interpolator that generates a reference clock having the same frequency as that of a received burst data signal and two types of determination clocks having a phase that is different from that of the reference clock respectively; and a phase adjustment control circuit that can change the phase of the reference clock in units of M/2?. After beginning receiving of a burst data signal, the clock data recovery circuit sets a large phase change value at the first phase adjustment timing and reduces the change value in the second and subsequent phase adjustment timings, thereby realizing quick bit synchronization with the received burst data signal to generate a reference clock.

Abstract: Disclosed herein is a clock data recovery circuit including: a first phase detector; a loop filter; a charge pump; a voltage-controlled oscillator; a second phase detector; a phase correction information generation section; and a phase correction information addition section.

Abstract: A clock and data recovery device receives a serial data stream and produces recovered clock and data signals. The clock and data recovery device operates over a range of frequencies and without use an external reference clock. A first loop supplies a first clock signal to a second loop. The second loop modifies the first clock signal to produce the recovered clock signal and uses the recover clock signal to produce the recovered data signal. The first loop changes the frequency of the first clock signal based on frequency comparison and data transition density metrics.

Abstract: A method of frequency search for a digitally controlled oscillator (DCO) with multiple sub-bands. The method comprises providing multiple workable pre-control codes, each control code comprising a most significant bit (MSB), corresponding to each frequency of the DCO for selection, selecting one of the workable pre-control codes according to the MSBs thereof, and providing the selected control code to the DCO.

Abstract: A system and method for low-cost performance and compliance testing of local oscillators and transmitters for wireless RF applications. A preferred embodiment comprises observing a digital signal from within an RF circuit, manipulating the signal with digital signal processing techniques, and determining if the RF circuit passes a test based upon results from the manipulating. Since the signal is clocked at a much lower frequency than an RF output of the RF circuit and the manipulation is performed digitally, testing can be performed at different stages of the production cycle and expensive test equipment can be eliminated.

Abstract: Methods and apparatus are provided for pseudo asynchronous testing of receive paths in serializer/deserializer (SerDes) devices. A SerDes device is tested by applying a source of serial data to a receive path of the SerDes device during a test mode. The receive path substantially aligns to incoming data using a bit clock. A phase is adjusted during the test mode of the bit clock relative to the source of serial data to evaluate the SerDes device. The source of serial data may be, for example, a reference clock used by a phase locked loop to generate the bit clock. The phase of the bit clock can be directly controlled during the test mode, for example, by a test phase control signal, such as a plurality of interpolation codes that are applied to an interpolator that alters a phase of the bit clock.

Abstract: Through the use of a multi-step sweep, the present invention is capable of increasing the speed and improving the error resistance of a signal alignment. In a specific embodiment of the invention, a method for the signal alignment of a target signal and an adjustable signal is disclosed. The target signal is sampled using three or more phase shifted versions of the adjustable signal to obtain a group of target signal state values. Next, through reference to the group of target signal state values it is determined that an edge of the target signal lies between a first phase shifted version and a second consecutive phase shifted version. In response, the first phase shifted version is selected as the starting point for a second sweep. During the second sweep, the phase of the first phase shifted version is sequentially adjusted in relatively small incremental steps to minimize the phase difference relative to the target signal.

Abstract: A receiver (13) of user equipment, UE, (10) of a Universal Mobile Telecommunications System, UMTS, network receives a digitally encoded radio signal over a downlink (11) from a base station (12). A Digital Signal Processor, DSP, (14) of the UE (10) estimates BER of data bits of power control commands received in the signal during an out of synchronisation procedure. More specifically, the DSP (14) samples the amplitude with which the data bits are received and determines a ratio of functions of one or more moments of the sampled amplitudes. The DSP (14) then compares the determined ratio to one or more values of BER for different ratios in a look-up table to estimate BER.

Abstract: Circuits and methods are provided for adjusting a frequency of a local clock signal in approximating a frequency of a host clock signal. A phase locked loop generates a local clock signal having a first phase and a first frequency. An offset adjustment circuit receives timing information relating the local clock signal to an incoming data signal and calculates a phase offset and a frequency offset indicative of adjustments to be made to the local clock signal. A first phase interpolator generates a receive clock signal from the local clock signal, the receive clock signal having a second phase and a second frequency responsive to the phase and frequency offsets. A second phase interpolator generates a transmit clock signal from the local clock signal having a third frequency responsive to the frequency offset.

Abstract: A phase detection circuit includes a phase frequency detector for comparing a first input signal and a second input signal and outputting a first phase comparison signal and a second phase comparison signal, and a sensing circuit for sensing a pulse width difference between the first phase comparison signal and the second phase comparison signal and outputting phase detection signals which have different logic values.

Abstract: The present invention provides a method of processing signal data comprising generating a first clock signal and a second clock signal and processing the signal data using the first clock signal and the second clock signal. While processing the signal data, the phase difference between the first clock signal and the second clock signal is measured and corrected for so that a target phase difference between the first clock signal and the second clock signal is maintained.

Abstract: An FM radio with a wide frequency range operates in a cell phone without interfering with the VCO of the RF transceiver. The FM transceiver generates a VCO signal whose frequency varies by less than ±7% from the midpoint of a narrow first range. A synthesizer signal is generated by dividing the VCO frequency by a first divisor such that the synthesizer frequency varies over a lower frequency second range. The VCO frequency is also divided by a second divisor such that the synthesizer frequency varies over a third range. The upper limit of the second range falls at the lower limit of the third range. The lower limit of the second range is 85.5 MHz and the upper limit of the third range is 108.0 MHz. By also using a third divisor, a synthesizer signal with a range of 76-108 MHz is generated from the narrow first frequency range.

Abstract: A rapidly adjustable local oscillation (LO) module for use in a radio transmitter or a radio receiver includes an oscillation generating module and a high frequency switching module. The oscillation generating module is operably coupled to generate a plurality of local oscillations. The high frequency switching module is operably coupled to, for a first one of a plurality of transmission paths, provide one of the plurality of local oscillations when a first transmission path selection indication is in a first state and provide another one of the plurality of local oscillations when the first transmission path selection indication is in a second state and, for a second one of the plurality of transmission paths, provide the one of the plurality of local oscillations when a second transmission path selection indication is in a first state and provide the another one of the plurality of local oscillations when the second transmission path selection indication is in a second state.

Abstract: Methods and apparatus are disclosed, such as those involving clock and data recovery sampler calibration. One such method includes receiving an electronic data stream by a clock and data recovery (CDR) circuit comprising a data sampler and an edge sampler. The data stream includes data portions and transitioning portions. The method further includes conducting calibration of the CDR circuit. The calibration includes acquiring samples from the transitioning portions of the data stream using the data sampler; and calibrating the data sampler based at least partially on the samples acquired using the data sampler. The method allows one not only to improve performance, but also to improve yield and reduce testing and screening requirements without requiring any additional circuitry to detect the offsets and works with regular input signals.

Abstract: A receiver may include a clock and data recovery circuit, a detection circuit and a sampling clock generator. The clock and data recovery circuit may receive first data and sample the first data to generate recovered data in response to a reception sampling clock signal. The detection circuit may detect a frequency difference between a transmission sampling clock signal and the reception sampling clock signal by comparing the first data and the reception sampling clock signal to generate a frequency difference detection signal. The sampling clock generator may generate the reception sampling clock signal based on the frequency difference detection signal and a first reference clock signal. Therefore, a communication system including the receiver may effectively reduce a jitter noise.

Abstract: Burst mode clock and data recovery (BCDR) circuit and method capable of fast data recovery of passive optical network (PON) traffic. An over-sampled data stream is generated from an input burst data signal and a phase interpolator generates sampling clock signals using a reference clock and phase information. A phase estimation unit (PEU) determines a phase error in the over-sampled data streams; and a phase retrieval unit sets the phase interpolator with the respective phase information of the input burst data signal prior to reception of the input burst data signal.

Abstract: A disclosed data processing apparatus includes: a binarization unit binarizing input data based on a threshold voltage; a capture unit capturing data from a binary output binarized by the binarization unit; a duty cycle detection unit detecting a duty cycle of the binary output; and a control unit controlling a level of the input data based on the duty cycle detected by the duty cycle detection unit.

Abstract: An adaptive equalizer for high-speed serial data comprises a programmable equalizer for equalizing an input serial data signal to generate an equalized serial data signal, wherein the equalization is based on an optimal equalization mode; a signal quality meter for computing an eye width indication based on the equalized serial data signal, wherein the eye width indication is an indicative of the quality of the equalized serial data signal; and a decision unit for determining the optimal equalization mode based on the eye width indication.

Abstract: A high-accuracy and computational efficient phase-discriminating device is provided and includes a phase-discriminating unit. The phase-discriminating unit converts an input and a reference signals into an input and a reference sequences respectively by a one-bit A/D conversion operation, determines a first value, an in-phase component and a quadrature component of the input signal in response to the input and the reference sequences, and produces an estimated phase of the input signal according to a relation among the first value, the in-phase component and a polarity of the quadrature component, wherein the first value is a certain integer being one of a first integer and a second integer, the first integer is a sampling count of the one-bit A/D conversion operation for producing the input sequence, and the second integer is a summation of an absolute value of the in-phase component and that of the quadrature component.

Abstract: The invention relates to a method or to a correspondingly equipped circuit for line-coupled generation of a clock (t), wherein the clock (t) is controlled in relation to a synchronization signal (hs) and by means of a closed loop (FLL) with respect to the phase and/or the frequency in relation to the synchronization signal (hs); wherein a plurality (n) of at least two count values (cn, c0-c7) is determined, wherein each of the count values (cn, c0-c7) is determined with at least one count duration number (z) of consecutive periods of the synchronization signal (hs), and wherein each of the count values (cn, c0-c7) is determined offset relative to at least one further count value (cn, c0-c7) with a count offset (v) which is different from the count duration number of consecutive periods of the synchronization signal (hs).

Abstract: A clock and data recovery circuit is disclosed and comprises a gated voltage-controlled oscillator (GVCO), a PLL unit, a phase-controlled frequency divider, a multiplexer, a matching circuit and a double-edge-triggered D flip-flop (DDFF). The GVCO receives a data signal and a reference voltage to generate first and second clock signals. The PLL unit receives a reference clock signal and generates the reference voltage to adjust the first and second clock signals at the vicinity of the predetermined frequency. The phase-controlled frequency divider receives and divides the first clock signal by N to output a third clock signal. The multiplexer controlled by a selection signal receives and outputs the second or the third clock signal. The matching circuit receives the data signal and the selection signal to match the delays therebetween. The DDFF receives the output signals from the matching circuit and the multiplexer, and outputs a recovered data signal.

Abstract: The present invention relates to a phase detector circuit (10) having an RF distribution device (20) which is intended to receive two sinusoidal high-frequency signals (RF, LO) with an input phase difference (?RF(t)??LO(t)) and comprises two power splitters (21, 22) in order to split the two high-frequency signals (RF, LO) into two respective parts, a self-calibrating phase detector module (30) which is configured to receive one respective part of the two high-frequency signals which have been split, a low-noise phase detector module (40) which is configured to receive the respective other part of the high-frequency signals which have been split, and a complementary filter device (50) which is configured to receive the output signals from the self-calibrating phase detector module (30) and the low-noise phase detector module (40) and to output a signal which indicates the time-dependent input phase difference between the two high-frequency signals (RF, LO).

Abstract: A method and a device for determining closed loop bandwidth characteristic of a Phase Locked Loop (PLL) (52) comprising a voltage controlled oscillator (VCO) (53) controlled by means of a tuning voltage (Vtune) is disclosed.

Abstract: A phase-locked loop includes: a voltage-controlled oscillator (VCO) system receiving one or more control signals and in response thereto generating a PLL output signal; a plurality of phase detectors for comparing a reference signal having a reference frequency to a PLL feedback signal having a PLL feedback frequency derived from the PLL output signal, and in response thereto to output a comparison signal; and a plurality of signal processing paths each connected to an output of a corresponding one of the phase detectors for outputting a phase detection output signal. The signal processing paths have different frequency responses from each other. In operation only one of the phase detectors is activated, and a switching arrangement selectively switches between outputs of the signal processing paths to select the phase detection output signal from the activated phase detector to generate the control signal(s) for the VCO system.

Abstract: There is provided an information processing apparatus includes a first module and a second module. The first module includes a first signal generator that produces a first signal by coding a first transmitted data into a waveform not including a direct-current component, having a polarity being inverted in each half period of a clock; a first signal sending unit that sends the first signal; and a signal subtracting unit that subtracts the first signal from a received signal. The second module includes a clock detecting unit that detects the clock based on the polarity inverting period of the first signal received from the first module; a second signal generator that produces a second signal by coding a second transmitted data into a waveform not including the direct-current component; and a second signal sending unit that sends the second signal while the second signal is synchronously added to the first signal.

Abstract: A novel interpolating phase detector for use in a multiphase PLL is described comprising an array of individual phase comparators, all operating at essentially the same operating point which permits the circuits to be designed simultaneously for high speed and for low power consumption. Two adjacent phase outputs of a multi-phase VCO may be selected and interpolated in between, by selectively attaching a variable number of phase comparators to each phase output and summing their phase error outputs. By varying the number of phase comparators attached to each phase output, interpolation can be achieved with high linearity.