Ciena Corporation

Nortel Networks Corporation

Rockstar Consortium US LP

Christopher Kurowski

Naim Ben-Hamida

Sadok Aouini

Mohammad Honarparvar

Soheyl Ziabakhsh Shalmani

Lukas Jakober

Hazem Beshara

Junxian Weng

Tom M Luk

Robert G Gibbins

Youssef Karmous

Described are apparatus and methods for fractional synchronization using direct digital frequency synthesis (DDFS). A DDFS device includes a memory with N address spaces, a write port circuit configured to sequentially write a digital desired pattern into the N address spaces, a read port circuit configured to readout the digital desired pattern from the N address spaces using continuous sequential automatic addressing from 0 to N&#x2212;1 at a memory operating frequency clock, where the memory operating frequency clock is based on a sampling frequency clock used for high-speed data processing, and an analog signal processing circuit configured to process a readout digital desired pattern into an analog representation; and output a synthesized frequency clock from the analog representation to a digital core, where the synthesized frequency clock is fractionally synchronized with the sampling frequency clock.

Apparatus and methods for fractional synchronization using direct digital frequency synthesis

Described herein are apparatus and methods for a high bandwidth under-sampled successive approximation register (SAR) analog to digital converter (ADC) (SAR ADC) with non-linearity minimization. A method includes sampling, by a sampling switch triggered by a sampling clock in the SAR ADC, an input signal, determining, by a comparator in the SAR ADC, a value for a bit based on comparing the sampled input signal to a reference signal provided by a reference digital-to-analog (DAC) in the SAR ADC, wherein the input signal and the reference signal propagate through substantially similar input paths, resampling, by the sampling switch, the input signal for each successive bit, determining, by the comparator, a value for each successive bit based on comparing the resampled input signal and a reference signal for each successive bit, and outputting, by a digital controller, a digital result after determining a value for a last bit by the comparator.

High bandwidth under-sampled successive approximation register analog to digital converter with nonlinearity minimization

Described are apparatus and methods for analog to digital converter (ADC) with factoring and background clock calibration. An apparatus includes an ADC configured to sample and convert differential input signals using a reference clock to obtain a defined number of samples during a first state in an acquisition clock cycle, and a finite state machine circuit configured to obtain the defined number of samples from the ADC using a clock based on the reference clock, factor the defined number of samples based on at least a common mode offset associated with the ADC, and send offset factored output to a controller.

High resolution analog to digital converter with factoring and background clock calibration

Described are apparatus and methods for successive approximation register (SAR) analog to digital converter (ADC) (SAR ADC) with factoring and background clock calibration. An apparatus includes a SAR ADC configured to, in response to receiving an enable flag based on detection of an acquisition clock with a first logic state sent by a controller, sample and convert a pair of differential input signals using a sampling clock to obtain a defined number of samples in an acquisition clock cycle and a factoring circuit configured to obtain the defined number of samples from the SAR ADC using a capturing clock based on the sampling clock, factor the defined number of samples, and send a factored samples ready flag to the controller.

High resolution successive approximation register analog to digital converter with factoring and background clock calibration

A receiver gain tracking loop utilizing two Digital-to-Analog Converters (DACs) and methods for operating the gain tracking loop are provided. The gain tracking circuit includes a signal detector for detecting at least one signal and outputting a detected signal; a digital integrator connected in series to the signal detector for integrating the detected signal in the digital domain; two DACs connected in parallel to the digital integrator; and an analog summing element for summing the first digital output and the second digital output of the DACs producing a combined output.

Coarse-fine gain-tracking loop and method of operating

A method for clock recovery that may include obtaining an output signal from a phase locked loop (PLL) device. The method may further include determining, using a digital phase detector, the output signal, and a transmitter clock signal, an amount of phase difference between the output signal and the transmitter clock signal. The method may further include filtering, using a phase rotator and a digital accumulator, a portion of the amount of phase difference from the output signal to generate a filtered signal.

Optical clock recovery using feedback phase rotator with non-linear compensation

A method and system for multiplexing data signals is provided. A first circuit is operable to generate a plurality of serialized data signals and is operable to adjust a phase of at least one of the serialized data signals to adjust bit and byte alignment. A second circuit is coupled to the first circuit to receive the plurality of serialized data signals from the first circuit. The second circuit has a multiplexer operable to generate a multiplexed output signal from the received serialized data signals. The first circuit is further coupled to the second circuit by a back channel operable to carry information regarding bit alignment and byte alignment of the received serialized data signals.

Method and system for phase and byte alignment on a multiplexed high speed bus

A method and system for multiplexing a plurality of serialized data signals in which a first integrated circuit device generates a plurality of serialized data signals. A second integrated circuit device is in electrical communication with the first integrated circuit device. The second integrated circuit device includes a multiplexer operable to generate a multiplexed output signal from the plurality of serialized data signals received from the first integrated circuit. A phase data and byte snapshot back channel is transmitted from the second integrated circuit device to the first integrated circuit device. The phase data and byte snapshot back channel carries phase data and periodic snapshots of the serialized data signals. The phase data and byte snapshot back channel is used by the first integrated circuit device to adjust the phase of each of the plurality of serialized data signals to preserve bit and byte alignment. Such a method and system can be implemented as a 4&#xd7;10 Gbit/Sec. system that is multiplexed to a 40 Gbit/Sec. stream as may be used in optical transmission systems.

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Nepean, Canada

Christopher Kurowski