Kestrel Solutions, Inc.

David B Upham

Minnie Ho

Norman L Swenson

James F Coward

Laurence J Newell

David Alan Pechner

Nicholas Joseph Possley

Michael W Rowan

Abraham H Kou

Augustus Elmer

Peter H Chang

Ting K Yee

Stuart E Wilson

Return-to-zero (RZ) formatted data is recovered and transmitted using non-return-to-zero (NRZ) devices. A NRZ clock and data recovery device (CDR) interprets the clock rate of a RZ formatted signal as twice its actual clock rate. Due to this interpretation, extra zeroes will be inserted in the data stream. The extra zeroes introduced by the NRZ interpretation of the data are discarded, and the interpreted clock rate is divided resulting in preserving the values of the original data stream of the RZ formatted signal. A NRZ encoded data stream at a specific clock rate is processed so that when the data stream is transmitted to a recipient expecting RZ formatted data, the recipient interprets the correct data.

Recovery and transmission of return-to-zero formatted data using non-return-to-zero devices

A frequency division multiplexing (FDM) node used in optical communications networks provides add-drop multiplexing (ADM) functionality between optical high-speed channels and electrical low-speed channels. The FDM node includes a high-speed system and an ADM crosspoint. The high-speed system converts between an optical high-speed channel and its constituent electrical low-speed channels through the use of frequency division multiplexing and preferably also QAM modulation. The ADM crosspoint couples incoming low-speed channels to outgoing low-speed channels, thus implementing the ADM functionality for the FDM node.

Optical communications networks utilizing frequency division multiplexing

A frequency division multiplexing (FDM) node used in optical communications networks provides add-drop multiplexing (ADM) functionality between optical high-speed channels, and low-speed tributaries. The FDM node includes a high-speed system and an ADM crosspoint. The high-speed system converts between an optical high-speed channel and its constituent electrical, low-speed channels through the use of frequency division multiplexing. The ADM crosspoint couples any incoming low-speed channels and any incoming tributaries to any outgoing low-speed channels and tributaries, thus implementing the ADM functionality for the FDM node.

Electrical add-drop multiplexing for optical communications networks utilizing frequency division multiplexing

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Sunnyvale, CA, United States of America

David B Upham