A method includes determining a phase error for a first clock signal and a second clock signal and determining an offset based on the phase error for the first clock signal and the second clock signal. The method also includes adding the offset to a phase of the first clock signal to produce a first adjusted clock signal and subtracting the offset from a phase of the second clock signal to produce a second adjusted clock signal. A phase error for the first adjusted clock signal and the second adjusted clock signal is smaller than the phase error for the first clock signal and the second clock signal.

A method of frequency search and error correction of clock and data recovery circuit, comprising: initializing a frequency search algorithm parameter; processing a frequency error parameter UP/DN signals according to the set algorithm parameter and starting the frequency search, in which, the algorithm accordingly counts the UP/DN signals. When a phase error signal transition occurs, a transition parameter JUMP is accumulated by 1, and an accumulation parameter SUM is obtained and is further judged that whether a frequency search result is to be output. Number of repeating times of verification and threshold parameters are set, accordingly a reset DCRL value is obtained to verifies a frequency locking result and outputs the result. The present invention improves accuracy of UP/DN pulse counting, increases stability and reliability of the frequency locking, avoids a false locking in the frequency locking, and prevents an excessive locking time in the frequency locking, overcomes error judgment of the frequency search caused by a random jitter, and correctly completes the frequency search and locking, avoids failure of the CDR caused by an error frequency locking.

An eye opening monitor device and an operation method thereof are provided. The eye opening monitor device includes a phase interpolator, a first sampling circuit, a second sampling circuit, and a clock centering circuit. The first sampling circuit samples a data signal according to a data clock to generate first sampled data. The second sampling circuit samples the data signal according to a phase interpolation clock to generate second sampled data. The phase interpolator changes a phase of the phase interpolation clock according to a phase interpolation code. The clock centering circuit counts multiple comparison results of the first sampled data and the second sampled data in multiple clock cycles to obtain an error count value for any one of different phase interpolation codes. The clock centering circuit determines the phase interpolation code provided to the phase interpolator based on the error count values corresponding to different phase interpolation codes.

The present invention relates to a field programmable gate array system that provides phase control with minimal latency.

The present invention relates to a field programmable gate array system that provides phase control with minimal latency.

A clock and data recovery circuit includes a voltage controlled oscillator, a frequency detector and a control circuit. The voltage controlled oscillator is configured to generate a clock signal according to a voltage signal. The frequency detector is configured to detect whether increasing a frequency of the clock signal is required according to a plurality of sampling results of the input data signal and accordingly generate a first up control signal. The control circuit is coupled to the voltage controlled oscillator and the frequency detector and configured to adjust the voltage signal according to the first up control signal. The clock and data recovery circuit operates in a data recovery mode after detecting that the frequency of the clock signal is locked, and the frequency detector is configured to detect whether increasing the frequency of the clock signal is required in the data recovery mode.

An apparatus for generating an output signal having a waveform that is repeated every period, includes a storage configured to store values corresponding to the waveform in a portion of a period of the output signal, a counter configured to generate a first index of a sample included in the output signal, a controller configured to generate at least one control signal based on the first index and the period of the output signal, and a calculation circuit configured to generate the output signal by calculating an output from the storage based on the at least one control signal.

Disclosed are some examples of retimer circuitry, systems and methods. In some implementations, clock data recovery circuitry is coupled between a receiver and a transmitter. The clock data recovery circuitry is configured to: extract a data component from an input data signal associated with the receiver, provide the data component to the transmitter, and generate a phase control signal. Phase interpolator circuitry is coupled with the clock data recovery circuitry. The phase interpolator circuitry includes a phase interpolator configured to: receive the phase control signal, generate, based on the phase control signal, an output clock signal, and provide the output clock signal to the transmitter to track data packets of the data component.

A semiconductor device has a current controlled oscillation circuit configured to generate an oscillation clock in response to a current supplied, a first circuit configured to output a first signal when a phase of the oscillation clock is later than a phase of reception data, and to output a second signal when a phase of the oscillation clock is earlier than a phase of the reception data, and a current control circuit configured to control a current to be supplied to the current controlled oscillation circuit such that the number of times of output of the first signal from the first circuit matches the number of times of output of the second signal from the first circuit.

A circuit includes a voltage-controlled oscillator (VCO) and a frequency divider. The frequency divider input is coupled to the VCO output. The circuit further includes a phase-frequency detector (PFD). A control output of the PFD is coupled to the VCO. A first PFD input is coupled to a first frequency divider output, and a second PFD input is coupled to a second frequency divider output. The first frequency divider output is configured to provide a first frequency divider signal and the second frequency divider output is configured to provide a second frequency divider signal 90 degrees out of phase with respect to the first frequency divider signal. The PFD is configured to detect an occurrence of at least two edges of a signal on the data input while the second frequency divider signal is continuously logic high across the at least two edges.