82 results about "Skew" patented technology

A method for suppressing a skew between a first channel and a second channel in an optical transmission system having a transmitter that transmits an optical signal with the first channel and the second channel and a receiver that receives the optical signal, the method includes: controlling dispersion added to the optical signal to be larger than a specified amount; and controlling a delay time of at least one of the first channel and the second channel in the receiver based on a quality of the optical signal monitored in the receiver to suppress the skew between the first channel and the second channel in the receiver.

A method is provided for detecting the skew between parallel light signals generated from a serial data stream. The method can be used with polarization multiplexed signal, as well as with wavelength division multiplexed signals, spatial division multiplexed signals, phase modulated signals, or intensity modulated signals. The method can be used with direct detection schemes as well as with coherent detection schemes. The method is provided with: imprinting dips between a fixed number of transmitted symbols of the parallel signals; detecting an electrical signal related to the dips for each parallel signal; and comparing the electrical signals in delay.

Time-interleaved signal converter systems are provided that multiplex respective digital sequences of system converters into an interleaved digital sequence before filtering each respective digital sequence with digital filters that apply respective filter coefficients to thereby reduce system degradation caused by converter timing skews. Use of the interleaved digital sequence in the filtering process substantially increases the system bandwidth from approximately one half of the converter sample rate RC to approximately one half of a greater system sample rate RS. Converter system embodiments are preferably configured to reduce large timing skews prior to filtering the interleaved digital sequence to obtain further reduction. This combined approach has been found to enhance interleaved system performance.

Systems and methods for determining inline skew of one or more seismic streamers are disclosed. One system embodiment includes a seismic streamer including a plurality of receivers, a skew detector adapted to detect inline skew of the streamer, and a receiver selector adapted to select which receivers in the streamer to use in data acquisition based on the detected streamer inline skew. It is emphasized that this abstract is provided to comply with the rules requiring an abstract, which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Method for measuring and compensating skews of data transmission lines connecting at least one data transmission device with a data reception device via a parallel data bus comprising for each data transmission line the following steps: measuring the relative time delay of the data transmission line by transmitting a determined sequence of measurement vectors (MV) each consisting of an alternating bit pattern via said data transmission line, wherein the bit alternation frequency is halfed with every transmitted measurement vector (MV); comparing the received measurement vectors (MV′) transmitted via said data transmission line with corresponding reference vectors (RV) stored in said data reception device; shifting the received measurement vectors by inserting data unit intervals (UI) until a received measurement vector (MV′) matches a corresponding reference vector (RV); calculating a relative skew of the data transmission line depending of the number of inserted data unit intervals (UI) with respect to a slowest data transmission line; and compensating the calculated relative skew of the data transmission line by means of delay elements switched in response to the calculated relative skew.

To overcome these problems, the present invention generates two window strobes and uses the two window strobes to determine if skew between two signals meets predetermined criteria. One of the window strobes is used to test one of the signals, and the other window strobe is generated relative to the first window strobe. The second window strobe tests the other signal (or signals, if they are data signals). From the tests of the two window strobes, it can be determined if the skew between the first and second signals meets predetermined criteria. In particular, the two window strobes are placed relative to each other and to the signals being tested in such a way that when both window strobes indicate passing conditions, skew between the two signals is guaranteed.

A transmission system for transmitting a first differential signal includes a transmitter, a transmission path, and a receiver. The transmitter transmits the first differential signal and a second differential signal. The transmission path transfers the first differential signal and the second differential signal. The receiver receives the first differential signal and the second differential signal. The transmitter includes a generator circuit and a switch. The generator circuit generates the second differential signal lower in baud rate than the first differential signal. The switch selects between the second differential signal and the first differential signal to output the selected differential signal to the transmission path. The receiver includes a detector circuit and a corrector circuit. The detector circuit detects a skew of the second differential signal. The corrector circuit corrects a skew of the first differential signal based by the detected skew of the second differential signal.

For the purpose of providing technique by which even when large skew of a disk or a head occurs due to a thermal shock, an outside shock, or the like, a servo signal area is not extended, and a performance loss caused by head change is not produced, a servo detection control system according to the present invention comprises: a learning means by head change including a servo sector interval measuring unit for measuring an interval of servo signal areas, which may occur at the time of head change among a plurality of heads; a time difference calculating unit for calculating head-change time difference from a value measured by the servo sector interval measuring unit; and a time difference storage unit for storing a result of calculation made by the time difference calculating unit; and a compensation and control means for compensating start timing of servo detection after head change using a stored value of the time difference storage unit. In addition, the amount of head skew in a disk radius direction is measured using a writing signal in a servo sector after head change; and positioning of feed-forward of a head is controlled using the amount of head skew.

This algorithm and apparatus provides the ability to determine the amount of skew that should be injected into a high-speed data communications system consisting of a plurality of lanes comprising a data bus on a per lane basis, relative to a reference lane, for the purpose of compensating for inherent system skew. By knowing the relative amount of skew that each lane requires for alignment, an appropriate amount of skew can then be injected on each lane to provide alignment and thus compliancy with relevant standards, such as the Sxl-5 standard, in terms of data skew specifications. These relative skew amounts for each transmitting lane are determined using a methodology involving internal loopback and characteristics from the connected communications element to the chip receive path.

Time-interleaved signal converter systems are provided that multiplex respective digital sequences of system converters into an interleaved digital sequence before filtering each respective digital sequence with digital filters that apply respective filter coefficients to thereby reduce system degradation caused by converter timing skews. Use of the interleaved digital sequence in the filtering process substantially increases the system bandwidth from approximately one half of the converter sample rate RC to approximately one half of a greater system sample rate RS. Converter system embodiments are preferably configured to reduce large timing skews prior to filtering the interleaved digital sequence to obtain further reduction. This combined approach has been found to enhance interleaved system performance.

A method and apparatus for uplink power control based on power spectral density are disclosed. In one embodiment, the method for use by a terminal in a satellite communication system, the terminal having an antenna, a modem and a controller, the method comprising: determining the scan and skew of the antenna; obtaining, using the controller, a value representing a maximum allowed Power Spectral Density (PSD) for the determined scan and skew; determining, using the controller, a maximum allowable modem power based on the value representing a maximum allowed PSD, where the maximum allowable modem power is that which ensures that transmissions from the terminal do not exceed the maximum allowed PSD if the maximum allowable modem output power is not exceeded by the modem; sending, using the controller, an indication of the allowable modem output power to the modem; and performing one or more transmissions from the terminal based on modem outputs in accordance with the maximum allowable modem output power.

The present disclosure provides a system, circuit, and method for correcting clock skew in time-interleaved analog-to-digital converters. At least two clock signals are received along respective channels. A delay of a first channel, carrying a first clock signal, is accounted for by applying one or more first adjustment factors to the channels until an edge of the first clock signal is aligned with a transition point of a reference signal. The first clock signal is swapped to the second channel, and vice-versa. A value of the reference signal as sampled by the first clock signal is compared to values of the reference signal as sampled by the second clock signal to determine a skew of the second channel vis-à-vis the first channel, and one or more second adjustment factors are applied to the second channel based on the determined skew of the second channel.

A method of measuring the thickness of a thin layer formed on a substrate comprises generating a measured signal spectrum by reflecting a light off of the thin layer and analyzing a resulting reflected light. The method further comprises generating a theoretical signal spectrum based on a putative thickness of the thin layer, and computing a skew signal spectrum as a difference between the measured signal spectrum and the theoretical spectrum. The method still comprises computing a reliability index by dividing a reference index by an area of the skew signal spectrum and using the reliability index to update the theoretical signal spectrum in a regression fitting process.

Generating, during a first and second signaling interval, an aggregated data signal by forming a linear combination of wire signals received in parallel from wires of a multi-wire bus, wherein at least some of the wire signals undergo a signal level transition during the first and second signaling interval; measuring a signal skew characteristic of the aggregated data signal; and, generating wire-specific skew offset metrics, each wire-specific skew offset metric based on the signal skew characteristic.

A deskew system includes a first voltage control delay receiving a data signal and generating N-numbered delayed data signals obtained by delaying a phase of the data signal in units of 90 / N, where N is a natural number that is not less than 1. In response to a phase control signal, a second voltage control delay receives a clock and generates N-numbered delayed clocks by delaying a phase of the clock in units of 90 / N. A skew compensation control unit generates a plurality of skew control signals to compensate for skew between the data signal and the clock based on the data signal, the N-numbered delayed data signals, the clock, and the N-numbered delayed clocks.

A data handoff controller includes a counter coupled to supply a count value indicative of a skew between a first clock signal and a second clock signal. The first and second clock signal have a fundamental beat frequency. A greatest common factor circuit is used to determine the fundamental beat frequency and the second is reset based on the beat frequency. A sampling circuit samples first clock domain data with the second clock signal. The sampling circuit is controlled to sample, at least in part, based on the count value. The count value can be used to impose a blackout window in which data is not sampled to avoid sampling data around data transitions of the first clock domain data. The count value can also be used to select an edge of the second clock signal to use for sampling the first clock domain data to ensure first clock domain data is not sampled during data transitions.

Methods and systems are described for receiving a plurality of signals corresponding to symbols of a codeword on a plurality of wires of a multi-wire bus, and responsively generating a plurality of sub-channel outputs using a plurality of multi-input comparators (MICs) connected to the plurality of wires of the multi-wire bus, generating a plurality of wire-specific skew control signals, each wire-specific skew control signal of the plurality of wire-specific skew control signals generated by combining (i) one or more sub-channel specific skew measurement signals associated with corresponding sub-channel outputs undergoing a transition and (ii) a corresponding wire-specific transition delta, and providing the plurality of wire-specific skew control signals to respective wire-skew control elements to adjust wire-specific skew.

The invention discloses a DDR (Double Data Rate) time sequence and delay skew simulation evaluation method based on a lookup table. The time sequence simulation evaluation method comprises the following steps: step 1), performing time sequence simulation in advance on signal lines of various signal transmission component types and delay physical property types, and obtaining a unit length delay lookup table of the signal lines; step 2), dividing signal lines of signals to be analyzed into signal line sub segments, and determining the delay physical property type and line length of each signal line sub segment; step 3), obtaining the signal delay of each signal line sub segment by the lookup table; and step 4), summarizing the delays of various signal line sub segments and obtaining a total delay of the signals to be analyzed; the delay skew simulation evaluation method subtracts the total delay of two signals to be analyzed and calculates the delay skews of the two signals to be analyzed. The DDR time sequence and delay skew simulation evaluation method based on the lookup table provided by the invention can simply and quickly perform simulation evaluation on the DDR signal delay and skew, and provide fast and accurate time sequence evaluation and design reference for the DDR signal design in view of the influences of different signal transmission components and delay physical properties.

Methods and systems are described for sequentially obtaining a plurality of data streams, the plurality of data streams comprising a data stream in a current condition, a data stream in a skewed-forward condition, and a data stream in a skewed-backward condition, calculating, for each data stream in the plurality of data streams, a corresponding set of cost-function values by obtaining a corresponding set of eye measurements, the eye measurements obtained by adjusting a sampling threshold of a sampler generating a plurality of samples of the data stream, the plurality of samples comprising edge samples and data samples, wherein the data stream is sampled at a rate equal to twice a rate of the data stream and calculating the corresponding set of cost-function values based on the corresponding set of eye measurements, and generating a skew control signal based on a comparison of the sets of calculated cost-function values.

A quadrature modulator (QM) may be calibrated by determining total equivalent offsets in the I- and Q-channels, a total equivalent gain imbalance between the I- and Q-channels, and a total equivalent phase skew between the I- and Q-channels. These values may be obtained by taking various scalar measurements of the image to signal ratio (ISR) and carrier to signal ratio (CSR) of the QM, while alternatively altering the system gain imbalance, system phase skew, I-channel offset and Q-channel offset using a respective gain parameter, phase parameter, I-channel offset parameter, and Q-channel parameter. The gain and phase parameters may be defined in terms of the ISR, and the channel offset parameters may be defined in terms of the CSR. The system gain imbalance, system phase skew, and total offset in the channels may then be calculated based on the various ISR and CSR measurements.

An analog to digital converter (ADC) device includes ADC circuitries, a calibration circuitry, and a skew adjustment circuitry. The ADC circuitries are configured to convert an input signal according to interleaved clock signals, in order to generate first quantization outputs. The calibration circuitry is configured to perform at least one calibration operation according to the first quantization outputs, in order to generate second quantization outputs. The skew adjustment circuitry is configured to determine maximum value signals, to which the second quantization outputs respectively correspond during a predetermined interval, and to average the maximum value signals to generate a reference signal, and to compare the reference signal with each of the maximum value signals to generate adjustment signals, in order to reduce a clock skew of the ADC circuitries.

A system for a backplane that employs i) an adjustment of positive-to-negative (P-N) driver skew of a transmit signal of a relatively high-speed differential driver to reduce far-end crosstalk, ii) a high-speed differential subtraction circuit combining a gain-adjusted replica of at least one transmit signal with a received signal to reduce near-end crosstalk, and iii) a phase-locked loop (PLL) synchronization circuit to align timing events between a set of near-end and far-end high-speed interfaces.

An apparatus for determining the amount of skew to be injected into a high-speed data communications system of including a plurality of lanes having a data bus per lane, relative to a reference lane, for system skew compensation. By knowing the relative amount of skew that each lane requires for alignment, an appropriate amount of skew can be injected on each lane to provide alignment and thus compliancy with the SFI-5 and SxI-5 standards, in terms of data skew specifications. The relative skew amounts for each transmitting lane are determined using a methodology involving internal loopback and characteristics from a connected communications element to the chip receive path.

The invention relates to a tri-mode probe with automatic skew adjustment. A probe, including a first input configured to receive a first input signal, a second input configured to receive a second input signal, a first cable connected to the first input, a second cable connected to the second input, an electronically adjustable delay connected to the first cable, the electronically adjustable delay configured to delay the first input signal to remove a skew between the first input signal and the second input signal, and an amplifier configured to receive the first input signal from the electronically adjustable delay and a second input signal.

A system and method are provided for calibrating temporal skew in a multichannel optical transport network (OTN) transmission device. The method accepts a pair of 2n-phase shift keying (2n-PSK) modulated signals, as well as a pair of 2p-PSK modulated signals. The 2n-PSK and 2p-PSK signals are converted to 2n-PSK and 2p-PSK optical signals, respectively. The 2n-PSK and 2p-PSK optical signals are orthogonally polarized and transmitted. A timing voltage is generated that is responsive to the intensity of the orthogonally polarized signals. The timing voltage is correlated to a reference frame calibration pattern associated with a preamble / header portion of an OTN frame. Then, the timing voltages associated with the Ix, Qx, Iy, and Qy signal paths are compared, and the misalignment between the timing voltages and the reference frame calibration pattern is minimized in response to adjusting time delay modules in the Ix, Qx, Iy, and Qy signal paths.

An analog to digital converter (ADC) device includes ADC circuitries, a calibration circuitry, and a skew adjustment circuitry. The ADC circuitries are configured to convert an input signal according to interleaved clock signals, in order to generate first quantization outputs. The calibration circuitry is configured to perform at least one calibration operation according to the first quantization outputs, in order to generate second quantization outputs. The skew adjustment circuitry is configured to determine maximum value signals, to which the second quantization outputs respectively correspond during a predetermined interval, and to average the maximum value signals to generate a reference signal, and to compare the reference signal with each of the maximum value signals to generate adjustment signals, in order to reduce a clock skew of the ADC circuitries.