Scientific-atlanta, Inc.

Other

Cisco Technology, Inc.

Lamar E West, Jr

Jiening Ao

Joseph Graham Mobley

John Alexander Ritchie, Jr

Steven E Blashewski

Donald C Sorenson

Florin Farcas

James O Farmer

John W Brickell

Richard J Futch

Mark E Schutte

Emory L McGinty, Jr

Jesse M Still

Charles R Bramhall

Anthony John Wasilewski

Michael P Harney

Gregory S Durden

Jay C McMullan, Jr

David J Naddor

Randolph J Schaubs

Himanshu R Parikh

Thai-Bao H Kien

Robert J Beyers, Ii

Robert J Edwards

Donald R Huntley

William P Lafay

Ray T Haman, Jr

John A Kennedy

Douglas J Hoder

Donovan S White

David P Durand

Leo Montreuil

Leo J Thompson

Herman A Kruse

Frank R Little

Guy A Primiano

William B Thatcher

Alex M Cook, Jr

Steve Nussrallah

J Graham Mobley

Melvin Paulick

Anatoly Kozushin

Mark E Schuttte

Marshall B Johnson

Christopher P Lewis

Christopher B Plonsky

Majid Ghanouni

Pieter G Iberlings

John A Ritchie

The present invention is directed towards a frequency modulated (FM) burst mode optical system that allows optical signals having a common wavelength provided by a plurality of FM burst mode optical transmitters to be passively combined onto a single optical fiber. A single FM optical receiver receives the combined signals and processes them accordingly. Each FM burst mode optical transmitter includes an FM modulator, a carrier detect circuit and a laser. The FM modulator modulates a carrier signal, such as a 1.21 GHz signal, with received reverse electrical signals. When a subcarrier signal is detected by the carrier detect circuit, the laser is turned and the frequency modulated carrier signal is used to intensity modulate a laser to provide an optical signal. Due to the burst-mode transmission of optical signals, the optical signals can be passively combined and transmitted to a single optical receiver.

Frequency modulated burst mode transmitter and method

An architecture for providing high-speed access over frequency-division multiplexed (FDM) channels allows transmission of Ethernet frames and/or other data across a cable transmission network or other form of FDM transport. The architecture involves downstream and upstream FDM multiplexing techniques to allow contemporaneous, parallel communications across a plurality of frequency channels. Furthermore, the architecture allows a central concentrator to support a plurality of remote devices that each has guaranteed bandwidth through connection-oriented allocations of bi-directional data flows. The upstream and downstream bandwidth allocation can support symmetrical bandwidth as well as asymmetrical bandwidth in either direction. As a local network, the architecture supports guaranteed bandwidth for delivery of data flows to a plurality of host devices.

Clock synchronization in a bidirectional network

Frequency modulated burst mode optical system

The present invention is directed towards monitoring and adjusting a power level of reverse subcarrier signals at an input of an optical node as opposed to at an input of a CMTS blade. Advantageously, reverse subcarrier signals are digitally transmitted throughout the optical link thereby avoiding the use of attenuators in the optical link. Therefore, any attenuation of the power level of the reverse subcarrier signals is caused by an RF feeder portion of the communications system. The CMTS blade then detects the power level of the reverse subcarrier signal that is equivalent to the power level at the input of an optical node and sends a control signal to CPE adjusting the transmitter power level without affecting the optical node dynamic range.

Frontend baseband digital reverse for a cable modem termination system

An architecture for providing high-speed access over frequency-division multiplexed (FDM) channels allows transmission of ethernet frames and/or other data across a cable transmission network or other form of FDM transport. The architecture involves downstream and upstream FDM multiplexing techniques to allow contemporaneous, parallel communications across a plurality of frequency channels. Furthermore, the architecture allows a central concentrator to support a plurality of remote devices that each have guaranteed bandwidth through connection-oriented allocations of bi-directional data flows. The upstream and downstream bandwidth allocation can support symmetrical bandwidth as well as asymmetrical bandwidth in either direction. The architecture generally can be used to support connection-oriented physical layer connectivity between a remote device and the central concentrator. Furthermore, the architecture may be integrated into other higher level devices such as, but not limited to, bridges, switches, routers, and/or gateways. The architecture generally may peacefully coexist with other services commonly-found in cable distribution networks.

Multi-carrier frequency-division multiplexing (FDM) architecture for high speed digital service

A transmitter () for transmitting reverse optical signals in a broadband communications system () that includes a converter () for digitizing the analog RF signals and a carrier-detect circuit () coupled to the converter () for detecting when digital RF signals are present at the output of the converter (). When the carrier-detect circuit () detects digital RF signals, the carrier-detect circuit () allows the digital RF signals to be transmitted upstream through the broadband communications system (). A digital network () then combines the received digital RF signals with other digital RF signals from additional transmitters (). The combined digital signals are then provided to a receiver () that includes a converter () for returning the digital RF signals to analog RF signals and then providing the analog signals to a headend for further processing.

Burst-mode digital transmitter

Disclosed herein are methods of providing a client with local area network connectivity and access to other services in a cable network. One such method includes: allocating bandwidth in the network to support bi-directional data communication between the host and a central concentrator. Bandwidth is allocated for a downstream flow on at least one downstream frequency channel based on a mapping between the downstream flow and a particular octet in a downstream packet. Bandwidth is allocated for an upstream flow on at least one non-shared upstream tone. The method also includes conveying a bi-directional data flow between the host and the concentrator over the allocated bandwidth, including conveying the upstream flow using the allocated bandwidth and conveying the downstream flow using the allocated bandwidth. The method also includes utilizing bandwidth in the network not allocated to data communications to provide the host with at least one audio/visual service.

Multi-carrier frequency-division multiplexing (FDM) architecture for high speed digital service in local networks

An architecture for providing high-speed access over frequency-division multiplexed (FDM) channels allows transmission of ethernet frames and/or other data across a cable transmission network or other form of FDM transport. The architecture involves downstream and upstream FDM multiplexing techniques to allow contemporaneous, parallel communications across a plurality of frequency channels. Moreover, an automatic frequency control resolves some issues of a free-running clock in an upstream tuner of the central concentrator by performing adjustments based on the average frequency error of a number of active upstream tones. In the preferred embodiments of the present invention, the automatic frequency control (AFC) utilizes a feedback loop for at least each active upstream tone. Also, the average of the active upstream tones is determined and is utilized in providing feedback to adjust the automatic frequency control (AFC).

Automatic frequency control of multiple channels

The present invention is directed towards an open-loop thermal compensation circuit that is suitable for use in a burst-mode laser transmitter. The compensation circuit adjusts the optical power level to ensure that the laser diode remains at an optimum power level. The thermal compensation circuit includes a thermistor having a thermal current, which is dependent upon any temperature fluctuations, where the thermal current adjusts a laser current. A change in the laser current subsequently adjusts the optical power level. Also included is a control circuit for turning on and off the laser diode with a control current, which is dependent upon the presence or absence of incoming electrical signals.

Open loop thermal compensation circuit that is suitable for use in burst-mode laser transmitters

The present invention provides an apparatus and method for detecting the presence of a carrier signal that is included in the reverse signals of a communications system. The present invention uses an improved apparatus that determines the average power of the reverse signals during a predetermined counting cycle. The average power is then compared to a threshold power value. If the average power exceeds the threshold power value, an enable signal is provided to allow further transmission of the reverse signals.

Detecting a carrier signal by using a power averaging circuit

The present invention provides an improved apparatus and method for detecting a reverse carrier signal. The present invention utilizes a peak detector/envelope filter for determining the peak level of the reverse analog waveform. The peak level is compared to a threshold level during a predetermined time period to determine the presence of a valid reverse carrier signal. Once determined, an enable signal is provided to an electronics device that allows further transmission of the reverse signals.

Method and device for detecting the presence of a carrier signal transmitted in the reverse RF path

The present invention is directed towards a burst-mode combiner (BMC) typically located within a headend facility for transmitting received reverse signals to a specific application device dependent upon the presence of a carrier signal. The BMC includes BMC circuits that are each coupled to reverse receivers. The BMC circuits filter the reverse signals into specific frequencies. A carrier detect circuit detects the presence of a carrier signal, and when detected, allows the delayed reverse signals to be transmitted through to the application device.

Burst-mode combining of reverse path radio frequency signals

An optical commutator ( ) for combining optical signals emanating from a plurality of optical transmitters ( ). The commutator ( ) includes a plurality of input ports connected to each optical transmitter ( ) via an optical fiber ( ). The optical transmitters transmits the optical signals within a predetermined bandwidth. A switching means ( ) sequentially connects each of the plurality of input ports to an output port ( ), where each of the plurality of inputs ports is connected to the output port ( ) at a frequency greater than twice the predetermined bandwidth. The output port ( ) then provides a combined optical signal that includes the plurality of optical signals.

Reverse path optical combining using an optical commutator

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Maysville, GA, United States of America

Lamar E West, Jr