John Thomson Ritchie

US Patent:

20080092183, Apr 17, 2008

Filed:

Dec 11, 2007

Appl. No.:

11/953925

Inventors:

Donald Sorenson - Lawrenceville GA, US
Jiening Ao - Suwanee GA, US
Steven Blashewski - Duluth GA, US
John Brickell - Lawrenceville GA, US
Florin Farcas - Lawrenceville GA, US
Richard Futch - Lawrenceville GA, US
Joseph Mobley - Dunwoody GA, US
John Ritchie - Duluth GA, US
Lamar West - Maysville GA, US

International Classification:

H04N 7/173

US Classification:

725109000

Abstract:

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.

US Patent:

20080095083, Apr 24, 2008

Filed:

Dec 11, 2007

Appl. No.:

11/953941

Inventors:

Donald Sorenson - Lawrenceville GA, US
Jiening Ao - Suwanee GA, US
Steven Blashewski - Duluth GA, US
John Brickell - Lawrenceville GA, US
Florin Farcas - Lawrenceville GA, US
Richard Futch - Lawrenceville GA, US
Joseph Mobley - Dunwoody GA, US
John Ritchie - Duluth GA, US
Lamar West - Maysville GA, US

International Classification:

H04L 5/14

US Classification:

370295000

Abstract:

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.

US Patent:

55947263, Jan 14, 1997

Filed:

Mar 30, 1994

Appl. No.:

8/219848

Inventors:

Leo J. Thompson - Lilburn GA
Gregory T. Dubberly - Atlanta GA
John A. Ritchie - Duluth GA

Assignee:

Scientific-Atlanta, Inc. - Atlanta GA

International Classification:

H04J 100

US Classification:

370485

Abstract:

A broadband communications system for coupling telephony or other digital networks to a CATV network. The system transmits a multiplex of telephony signals in the forward band of the CATV network. Each forward channel is QPR modulated on a carrier and contains multiple subscriber telephony signals. The forward telephony channels are demodulated and demultiplexed by a plurality of subscriber terminals into the individual telephony signals directed to an addressed subscriber. Audio and control signals returning from the subscriber are digitized into standard telephony signals and QPSK modulated on a carrier onto the reverse band of the CATV network. The multiplicity of reverse band telephony channels are demodulated and multiplexed into a standard telephony signal which is directly interfaced to the telephony network. The reverse band modulators are frequency agile and modulate telephony signals from a subscriber in a selected one or more frequency subbands in the reverse band of the subscription network, so as to provide selectably changeable frequencies and selectably variable bandwidth in the reverse band commensurate with a selected subscriber communication feature. e. g. a single voice line, multiple voice lines, ISDN service, data communications services, security monitoring services, etc.

US Patent:

54992419, Mar 12, 1996

Filed:

Sep 17, 1993

Appl. No.:

8/123363

Inventors:

Leo J. Thompson - Lilburn GA
Gregory T. Dubberly - Atlanta GA
John A. Ritchie - Duluth GA
David M. Fellows - Beverly MA

Assignee:

Scientific-Atlanta, Inc. - Norcross GA

International Classification:

H04H 108

US Classification:

370 73

Abstract:

A broadband communications system for coupling telephony or other digital networks to a CTV network. The system includes transmitting a multiplex of telephony signals in 3 MHz channels in the forward band of the CTV network. Each 3 MHz channel is QPR modulated on a carrier and contains multiple subscriber telephony signals. The forward telephony channels are demodulated and demultiplexed by a plurality of subscriber terminals into the individual telephony signals directed to an addressed subscriber. The individually addressed telephony signal is then applied to a line card which connects the subscriber telephone equipment to the system. Audio and control signals returning from the subscriber are digitized into standard telephony signals and modulated on a carrier in 50 kHz reserved telephony channels onto the reverse band of the CTV network. The multiplicity of reverse band telephony channels are demodulated and multiplexed into a standard telephony signal which can be directly interfaced to the telephony network. In the illustrated embodiment, the CTV network has a fiber to the serving area architecture that can be used to increase the number of reverse band channels which are available to the broadband communications system.

US Patent:

57905231, Aug 4, 1998

Filed:

Jul 31, 1996

Appl. No.:

8/690628

Inventors:

John A. Ritchie - Duluth GA
Steve Idler - Bolingbrook IL
Gregory T. Dubberly - Atlanta GA

Assignee:

Scientific-Atlanta, Inc. - Norcross GA

International Classification:

H04J 116

US Classification:

370241

Abstract:

A test system for evaluating the operating state of a headend of a broadband communications network for communicating telephony signals between a telephony system and subscribers of communications services. Modulators at the headend transmit telephony signals in the forward band of the broadband communications network. The forward telephony channels are demodulated and demultiplexed by a plurality of subscriber terminals into individual telephony signals directed to an addressed subscriber. Signals returning from subscribers are digitized into standard telephony signals onto the reverse band of the broadband communications network, and demodulated by demodulators of the headend into a standard telephony signal that is interfaced to the telephony network. The test system evaluates the operating state of a selected demodulator of the headend by modulating a carrier with a predetermined data pattern to generate a upstream test signal. The upstream test signal is transmitted to the selected demodulator, which responds by outputting a detected upstream test signal.