Circuits, architectures, systems and methods for facilitating data communications and/or reducing latency in data communications. The architecture includes a clock recovery loop receiving data from a host device and providing a recovered clock signal, a filter circuit receiving recovered clock signal information and providing a control signal that adjusts the transmitter clock in response to recovered clock signal information and the two clock signals, and a transmitter receiving the control signal and transmitting data to a destination device in accordance with the transmitter clock. The circuitry generally includes a clock alignment block receiving first and second periodic signals and providing a control signal in response thereto, a filter for first periodic signal information, and a logic circuit configured to combine the control signal and the filtered information, thereby providing an adjustment signal for the second periodic signal. The systems generally relate to those that include the present architecture and/or circuit. The method generally includes determining a phase difference between first and second periodic signals, one of the periodic signals being recovered from a data stream; adjusting the other periodic signal in response to the phase difference and filtered information from the recovered periodic signal; and transmitting the data stream in accordance with said adjusted periodic signal. The present invention advantageously eliminates a FIFO memory in the data path, thereby reducing transceiver latency and improving system performance.

Architectures, circuits, systems and methods for reducing latency in data communications

A clock generation circuit is provided and includes a phase locked loop (PLL) and a calibrator. The PLL is arranged to receive a first clock signal and generate the output clock signal. The PLL adjusts the frequency of the output clock signal according to a control signal. The calibrator is arranged to receive the output clock signal and a second clock signal, execute a frequency calibration between the output clock signal and the second clock signal, and generate the control signal according to results of the frequency calibration.

Communication systems, clock generation circuits thereof, and method for generating clock signal

Disclosed is a spread spectrum clock generator comprising a phase interpolator, which receives a clock signal from a clock input terminal and a control signal (an up signal and/or down signal), for adjusting the phase of an output clock signal in accordance with said control signal and outputting the resultant clock signal, and a control circuit receiving and counting the clock signal that enters from the clock input terminal and outputting said control signal (up signal or down signal), which is for varying the phase of the output clock signal based upon the result of the count, to the phase interpolator. The phase of the output clock signal from the phase interpolator varies with time and the output clock signal is frequency-modulated within a prescribed frequency range. A changeover between absence and presence of a spread spectrum clock function is performed, without a sudden fluctuation in frequency, in accordance with a frequency-modulation start signal and frequency-modulation stop signal that enters from an SSC control terminal.

Spread spectrum clock generating apparatus

Transmit-side active signal management circuitry applies one or more active signal management processes to a digital signal at a transmit side of an interconnect. At the receive side of the interconnect, receive-side active signal management circuitry applies one or more corresponding active signal management processes, as appropriate, to the received digital signal to recover the information represented by the original digital signal. The interconnect can include a cable used to transmit the signals between a source device and a destination device, whereby one or both of the transmit-side active signal management circuitry and the receive-side active signal management circuitry is implemented at a corresponding cable receptacle of the cable. Alternately, one or both of the transmit-side active signal management circuitry and the receive-side active signal management circuitry can be implemented at a cable adaptor, thereby permitting the use of a passive cable interconnect to transmit the signal.

Skew management in cables and other interconnects

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.

Phase interpolator based transmission clock control

A device communicates with a host and includes a transmitter, a receiver and a clock generator that generates a signal having a local clock frequency. A clock recovery circuit communicates with the receiver and recovers a host clock frequency from data received from the host by the receiver. A frequency offset circuit communicates with the clock recovery circuit and the clock generator and generates a frequency offset based on the clock frequency and the recovered host clock frequency. A frequency compensator compensates a frequency of the transmitter using the frequency offset. The host and the device may communicate using a serial ATA standard. Frequency compensation can be performed during spread spectrum operation.

Clock offset compensator

Circuits, architectures, a system and methods for clock data recovery. The circuit generally includes (a) a clock phase adjustment circuit, receiving clock phase information and providing a clock phase adjustment signal, (b) a clock frequency adjustment circuit, receiving clock frequency information and providing a clock frequency adjustment signal, and (c) an adder circuit, receiving the clock phase adjustment signal and the clock frequency adjustment signal, and providing a clock recovery adjustment signal. The architectures and/or systems generally comprise those that include a clock data recovery circuit embodying one or more of the inventive concepts disclosed herein. The method generally comprises the steps of (1) sampling the data stream at predetermined times, (2) generating clock frequency information and clock phase information from sampled data, and (3) altering a frequency and/or a phase of the clock signal in response to the clock frequency information and the clock phase information. The present invention prevents or reduces the likelihood of the potential nonconvergence/clock runaway problem, advantageously with minimal or no changes to existing designs and logic. The present invention further advantageously improves system stability, reliability and performance with a minimum of additional circuitry.

Apparatus for clock data recovery

Circuits, architectures, a system and methods for clock data recovery. The circuit generally includes a clock phase adjustment circuit, receiving clock phase information and providing a clock phase adjustment signal, a clock frequency adjustment circuit, receiving clock frequency information and providing a clock frequency adjustment signal, and an adder circuit, receiving the clock phase adjustment signal and the clock frequency adjustment signal, and providing a clock recovery adjustment signal. The architectures and/or systems generally comprise those that include a clock data recovery circuit embodying one or more of the inventive concepts disclosed herein. The method generally comprises the steps of sampling the data stream at predetermined times, generating clock frequency information and clock phase information from sampled data, and altering a frequency and/or a phase of the clock signal in response to the clock frequency information and the clock phase information. The present invention prevents or reduces the likelihood of a potential nonconvergence/clock runaway problem, advantageously with minimal or no changes to existing designs and logic. The present invention further advantageously improves system stability, reliability and performance with a minimum of additional circuitry.

Circuits, architectures, a system and methods for improved clock data recovery

A storage device configured to communicate with a host according to a serial communication standard. The storage device includes a receiver configured to receive host data from the host; a clock data recovery circuit configured to determine a first frequency of host data transmitted by a host; a phase locked loop configured to generate a local phase corresponding to a local clock signal; a frequency offset calculator configured to generate a frequency offset corresponding to the first frequency and a second frequency of the local clock signal; an accumulator configured to generate a phase offset corresponding to a difference between the local phase and a phase of the host data; an interpolator configured to generate a compensated local clock signal using the phase offset and the local phase; and a transmitter configured to transmit device data to the host using the compensated local clock signal.

Lei Wu

Papers

Clock offset compensator

Apparatus for clock data recovery

Circuits, architectures, a system and methods for improved clock data recovery

Systems and methods for compensating a phase of a local clock of a storage device