Ciena Corporation

Nortel Networks Corporation

Northern Telecom Limited

Robert G Gibbins

Naim Ben-Hamida

Sadok Aouini

Douglas Stuart McPherson

Mahdi Parvizi

Yuriy Greshishchev

Steven William Wood

Anna Sakharova

Mohammad Honarparvar

Garnet Frederick Gibson

Soheyl Ziabakhsh Shalmani

Christopher Kurowski

Jerry Yee-Tung Lam

Andrew L Jarabek

Aris Tombul

Garnet Frederick Randall Gibson

Harvey Mah

Yalmez Yazaw

Youssef Karmous

An optical Digital Signal Processor (DSP) circuit includes a digital core configured to implement digital signal processing functionality and configured to operate at a plurality of baud rates including a full baud rate and a half-baud rate; and an analog interface including a Digital-to-Analog Converter (DAC) section and an Analog-to-Digital Converter (ADC) section, wherein the analog interface is connected to the digital core and is configured to operate at the full baud rate when the digital core is configured to operate at any of the plurality of baud rates.

Optical DSP operating at half-baud rate with full data rate converters

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 are apparatus and methods to calibrate and align multiple high-speed clock domains. A system includes at least two clock domains, a launch circuit connected to each of the at least two domains, and a calibration circuit. Each clock domain including a resettable device having a local reset retime clock. The launch circuit aligns a reset pulse with the local reset retime clock by using a launch clock from one of the domains, where the reset pulse is incoherent with respect to the domains, adjusts a delay of the launch clock to control a launch time of the reset pulse, and sends the reset pulse based on the delayed launch clock. The calibration circuit samples a local reset retime delayed clock to generate a readback signal. The launch circuit and the calibration circuit iterate through selected delays until safe arrival timing is indicated from each readout.

Multiple clock domain alignment circuit

Described are apparatus and methods for high frequency clock generation. A circuit includes a phase frequency detector (PFD) which outputs differential error clocks based on comparison of differential reference clocks and differential feedback clocks, which are at a first frequency. A controlled oscillator (CO) connected to the PFD, which adjusts a frequency of the CO based on the differential error clocks to generate differential clocks at a second frequency, which is a multiple of the first frequency. A quadrature clock generator connected to the CO, which generates differential quadrature clocks at the second frequency from the differential clocks, where the differential feedback clocks are generated from the differential clocks and one pair of the differential quadrature clocks. A frequency doubler which doubles each pair of the differential quadrature clocks and outputs fully differential and balanced clocks at a third frequency for distribution, which is a multiple of the second frequency.

Apparatus and methods for high frequency clock generation

A technique for provisioning cross-connects in network switching environment includes writing a first set of data into a first memory element during a first time interval and writing a second set of data into a second memory element during a second time interval. The technique reads a portion of the first set of data from the first memory element during the second time interval and reads a portion of the second set of data from the second memory element during a third time interval, and determines the first, second, and third time intervals based on a format of the sets of data, with the first time interval ending before the second time interval begins, and the second time interval ending before the third time interval begins.

Method and system for writing data to memory elements

Disclosed is an architecture of a RAM (random access memory) with BIST (built-in self test) or functional test function. The RAM has a memory cell for storing differential or single-ended binary data and bit line signals are fully differential or single-ended. Shadow write is applied to read only and read-write bit lines. With the test function, port-to-port bit line shorts and port-to-port word line shorts are sensitized.

Multi-port random access memory

Growing community of inventors

Stittsville, Canada

Robert G Gibbins