A data synchronization unit including first flip-flops, operating on a first clock domain and a reset of a second clock domain, sampling data from the first clock domain; a second flip-flop, operating in the first clock domain, sampling a request signal when enabled by a request pulse; a request signal path configured to delay the request signal by a first delay and to generate an enable signal for recirculation multiplexers in accordance with the delayed request signal; a reset signal synchronization path configured to delay the reset signal of the first clock domain by a second delay, wherein the second delay is shorter than the first delay; and multiplexers having first inputs for receiving outputs of the recirculation multiplexers, a second input for receiving a reset value of a programmable register, the multiplexers being configured to selectively output signals at inputs to outputs.

A clock-data recovery circuit includes a variable data path delay, an injection-locked oscillator having a free-running frequency, and circuitry for adjusting at least one of the variable data path delay and the free-running frequency, including a counter configured to count repetitions of a bit value in an input data signal, and further being configured to, on occurrence of a first data pattern in the input data signal, indicative of saturation of inter-symbol interference, measure the input data signal at a first clock edge to determine a first data phase measurement value, measure the input data signal at clock centers immediately preceding and immediately following the first clock edge to determine second and third data phase measurement values, and based on first predetermined relationships among the first, second and third data phase measurement values, adjust the variable data path.

A clock data recovery circuit includes a deglitch filter circuit and a timer circuit. The deglitch filter circuit is configured to remove pulses of less than a predetermined duration from a data signal to produce a deglitched data signal. The timer circuit is coupled to the deglitch filter, and is configured to compare a duration of a pulse of the deglitched data signal to a threshold duration, and identify the pulse as representing a logic one based on the duration of the pulse exceeding the threshold duration.

Embodiments of this application provide a method. A receiving device determines that a first PHY needs to be added to a first FlexE group in a working state; performs deskew on the first PHY or each PHY in the first FlexE group based on a received data stream corresponding to the first PHY and a received data stream corresponding to each PHY in the first FlexE group, and restores a data stream corresponding to a client from a PHY in the first FlexE group; and if skew between the data stream corresponding to the first PHY and the data stream corresponding to each PHY in the first FlexE group after the deskew is performed is zero, restores a data stream corresponding to a client from a PHY in a second FlexE group. Flexibility of adjusting a PHY in a FlexE group in a working state is improved.

A signaling system is disclosed. The signaling system includes a first integrated circuit (IC) chip to receive a data signal and a strobe signal. The first IC includes circuitry to sample the data signal at times indicated by the strobe signal to generate phase error information and circuitry to output the phase error information from the first IC device. The system further includes a signaling link and a second IC chip coupled to the first IC chip via the signaling link to output the data signal and the strobe signal to the first IC chip. The second IC chip includes delay circuitry to generate the strobe signal by delaying an aperiodic timing signal for a first time interval and timing control circuitry to receive the phase error information from the first IC chip and adjust the first time interval in accordance with the phase error information.

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.

An electric system comprising communication link between a signal transmitting end and a signal receiving end, wherein, at the signal transmitting end, a number of data bits are integrated into a low frequency signal to form an integrated signal. Each data bit is transmitted as part of a symbol. Each symbol comprises a predefined number of bits encoding at least one data bit, the state of some of the bits of each symbol being dependent on the state of the low frequency symbol.

An asynchronous data capture device comprises an edge spread detector circuit, a clock generator, and a data sampling circuit. The edge spread detector circuit uses a first clock frequency that is a multiple of a second clock frequency, identifies transitions in a data stream transmitted to the device at the second clock frequency, and determines a sampling point based on the identified transitions. The clock generator adjusts a phase offset based on the sampling point and generates a clock signal having the second clock frequency and the adjusted phase offset. The data sampling circuit uses the second clock frequency and samples the data stream at the sampling point. In some implementations, the edge spread detector determines a sampling point that is isolated from the identified transitions, and the clock generator adjusts the phase offset to cause a rising edge at the sampling point.

A method is provided for synchronizing a source device with a sink device. The source device transmits a stream of packets to the sink device. The source device receives feedback from the sink device indicating packet arrival times of the packets at the sink device. Based on the feedback, in some aspects, the source device determines an average time shift in the packet arrival times at the sink device, wherein the average time shift is relative to expected packet arrival times of the packets at the sink device. In some such aspects, the source device detects that the average time shift exceeds a threshold, and in response to the detecting, adjusts a streaming time of the stream of packets to synchronize, within a predefined tolerance, the source device with the sink device.

A signal conditioner for use in a serial data communications link. The signal conditioner including a tunable delay element responsive to a tuning signal to provide time domain delay modulation of the input data signals to generate conditioned (output) data signals, and phase comparator circuitry to generate the delay tuning signal based on a detected phase error between feedback conditioned data signals, and a reference signal. The tunable delay element and the phase comparator circuitry forming a delay-locked tuning loop to phase lock the conditioned data signals to the reference signal, independent of voltage domain frequency response. An example signal conditioner is a jitter attenuator/cleaner, where the bandwidth of the reference signal is lower than the bandwidth of the delay-locked tuning loop, to provide a low-jitter reference signal.