A circuit adapts to the occurrence of metastable states. The circuit inhibits passing of the metastable state to circuits that follow, by clock gating the output stage. In order to determine whether or not to gate the clock of the output stage, two detect circuits may be used. One circuit detects metastability and another circuit detects metastability resolved to a wrong logic level. The results from one or both detector circuits are used to gate the next clock cycle if needed, waiting for the metastable situation to be resolved.

A circuit adapts to the occurrence of metastable states. The circuit inhibits passing of the metastable state to circuits that follow, by clock gating the output stage. In order to determine whether or not to gate the clock of the output stage, two detect circuits may be used. One circuit detects metastability and another circuit detects metastability resolved to a wrong logic level. The results from one or both detector circuits are used to gate the next clock cycle if needed, waiting for the metastable situation to be resolved.

An example method of clock and data recovery in a receiver includes generating data samples and crossing samples of a received signal based on a data phase and a crossing phase, respectively, of a sampling clock supplied by a phase interpolator in the receiver; generating a phase detect result signal in response to phase detection of the data samples and the crossing samples; filtering the phase detect result signal to generate a phase interpolator code, the phase interpolator generating the sampling clock based on the phase interpolator code; determining an average phase detect result from the phase detect result signal; and adjusting the phase interpolator code in response to the average phase detect result being less than a threshold value.

A position-measuring device includes a position-sensing unit, a processing unit, an interface unit, a clock generator and a time measurement unit position-sensing unit configured to generate digital position values. The processing unit processes instructions from subsequent electronics. The interface unit communicates with the subsequent electronics, according to rules of an interface protocol, via at least one interface line that transmits interface signals having a temporal behavior that is determined by the interface protocol so as to transmit the instructions from the subsequent electronics to the processing unit. The clock generator generates a clock signal that serves as a time base for functions of the position-sensing unit and the processing unit. The time measurement unit uses the clock signal as a time base, receives at least one interface signal and measures a time interval between a start event and a stop event of the at least one interface signal.

An unlock detector includes a checker, an accumulator, and a comparator. The accumulator is electrically connected to the checker, and the comparator is electrically connected to the accumulator. The checker includes several checking units. The checker is configured to receive a sampled data signal and a sampled edge signal, and to check the sampled data signal and the sampled edge signal via the checking units to generate several checking results. The accumulator is configured to generate a counting value in a manner of counting according to the checking results. The comparator is configured to compare the counting value with a threshold to generate an unlock-detecting result.

A system on a chip (SOC) is configured to support multiple time domains within a time-sensitive networking (TSN) environment. TSN extends Ethernet networks to support a deterministic and high-availability communication on Layer 2 (data link layer of open system interconnect OSI model) for time coordinated capabilities such as industrial automation and control applications. Processors in a system may have an application time domain separate from the communication time domain. In addition, each type time domain may also have multiple potential time masters to drive synchronization for fault tolerance. The SoC supports multiple time domains driven by different time masters and graceful time master switching. Timing masters may be switched at run-time in case of a failure in the system. Software drives the SoC to establish communication paths through a sync router to facilitate communication between time providers and time consumers. Multiple time sources are supported.

A radar monolithic microwave integrated circuit (MMIC) includes a trigger encoder configured to receive a clock signal comprising a plurality of clock pulses having a fixed amplitude and a trigger signal configured to indicate trigger events. The trigger encoder is configured to encode the trigger signal into the clock signal to generate a distributed clock signal by skipping at least one clock pulse of the plurality of clock pulses to indicate a trigger event. The radar MMIC is configured to output the distributed clock signal having the at least one clock pulse skipped to indicate the trigger event. The radar MMIC is configured to receive the distributed clock signal as a received distributed clock signal. The radar MMIC further includes a radar operation controller configured to detect the trigger event based on the received distributed clock signal and initiate a radar operation based on detecting the trigger event.

A method includes receiving an optical signal through an optical link and determining a receiving power for the optical link. The method further includes comparing the receiving power for the optical link to a first receiving power threshold and transitioning a clock and data recovery circuit form a normal mode to a holdover mode when the receiving power is less than the first receiving power threshold. The clock and data recovery circuit, when operating in the holdover mode, configured to hold a recovered clock to a known-good clock frequency. When the receiving power for the optical link is greater than a second receiving power threshold, the method initiates a transition of the clock and data recovery circuit from the holdover mode to the normal mode and reacquires synchronization between the recovered clock and a current rate of the incoming data stream using the known-good clock frequency.

A CDR control circuit detects a phase shift of input data that is taken in with a phase-adjusted clock, and generates phase control data that controls the phase of the clock based on the detected phase shift, the CDR control circuit includes a change detection circuit that detects an over-change in the phase shift; and a selection circuit that outputs the phase shift before the change, which is the phase shift before the time of detection of the over-change, as the phase shift for a predetermined period of time at the time of detection of the over-change, wherein during the predetermined period of time, the phase control data is generated based on the phase shift before change.

An integrated circuit includes a plurality of receivers, each having a clock and data recovery circuit. A first local clock recovery circuit in a first receiver can be caused to produce a test clock which simulates a condition to be tested, and while a second receiver in the plurality of receivers that includes a second local clock recovery circuit is caused to use the test clock in place of the reference clock while receiving a test data sequence at its input. The clock and data recovery circuits in the receivers can include clock control loops responsive to loop control signals to modify the selected reference clock to generate the local clock in response to selective one of (i) a corresponding data signal for normal operation or during a test, and (ii) a test signal applied to the clock control loop in which case the test clock is produced.