Scientific-atlanta, Inc.

Certusview Technologies, LLC

Other

Lamar West

James O Farmer

Robert O Banker

Joseph Graham Mobley

Ronald Totten

John E Tumblin

Gregory C Cole

Blair J Schodowski

Michael P Harney

William T Murphy

Steve Nussrallah

Roy L Lowcock

Mark Doremus

Philip A Blusiewicz

An HFC cable communication system comprising: a CMTS having a first attenuator to attenuate one or more upstream signals applied to the CMTS; an optical link having a dynamic range and comprising an optical receiver having a second attenuator to attenuate the upstream signal(s) and an optical transmitter having a third attenuator to attenuate the upstream signal(s); a coaxial RF link comprising one or more RF amplifiers having a fourth attenuator to attenuate the upstream signal(s); and one or more subscriber modems to generate the upstream signal(s) at respective transmit RF signal levels. The CMTS implements a long loop ALC to set the transmit RF signal level(s) based on received RF signal levels of the upstream signal(s) at the CMTS. Respective values for the first, second, third and fourth attenuators are selected based on the dynamic range of the optical link so as to facilitate implementation of the long loop ALC and effective transmission of upstream information carried by the upstream signal(s).

Cable communication system optical nodes having selectable attenuation values to mitigate distortion of upstream information

Hybrid fiber-coaxial (HFC) cable communication systems having well-aligned optical and radio-frequency links to facilitate upstream channel plans having high aggregate data capacity

The invention is directed to an improved scrambler capable of self-calibrating output signals. In one embodiment, the scrambler provides an encoded signal along separate signal pulses. A portion of one signal is made to correspond to a portion of another signal to thereby self-calibrate the signals. Also, portions of the incoming video signal are forced to correspond with internally generated voltage level signals.

Scrambler with self-calibration

This invention discloses a new and improved method of scrambling video signals by inversion of the video information by splitting the sync pulse into plural portions and transmitting each portion of the sync pulse at a predetermined level. This improves the quality of the recovered video compared with other video inversion systems by rendering the video less sensitive to variations in the modulation depth of the modulator carrying the inverted signal, the demodulation sensitivity of the demodulator and the stability of the recovery circuits. The invention further provides additional security against pirating by allowing the scrambling circuit to operate in diverse modes, each of which will cause a TV to react differently should a conventional pirating device be employed. The invention also renders the signal capable of being transmitted with unmodified modulators of the type normally employed in the CATV industry.

Method and apparatus for improving video scrambling and employing split

Off premises cable television interdiction apparatus comprises a microprocessor actuation and control means for actuating and controlling one or more frequency agile voltage controlled oscillators. The voltage controlled oscillators selectively jam only unauthorized premium programming transmitted in the clear from a headend to a particular subscriber. Each voltage controlled oscillator is allocated a continuous band of frequencies consistent with the elimination of jamming signal frequency harmonics which may disturb authorized programming at a higher channel frequency. The microprocessor actuation and control means provides a calibration mode and a normal mode of operation. The method of interdiction comprises the steps of generating and storing voltage control words for operating the oscillators consistent with a head end selected jamming factor for a particular channel to be jammed and addressably transmitted and stored premium programming authorization data. An optimum frequency amplitude window for the jamming signal is disclosed.

Optimum amplitude and frequency of jamming carrier in interdiction

Equipment for use in CATV lines and a system for distribution of CATV signals and for power to operate CATV line equipment having active devices which require power is described. The system distributes CATV signals to subscribers who have ordered different levels of service (basic service without premium channels or different groups of premium channels). Housings are located in proximity to the premises of both actual subscribers and potential subscribers, and have like covers which contain tapping electronics (a directional coupler, line equalizers and power bypassing circuit). The cover has ports at opposite ends and an additional port at one end. The tapping electronics is located on a seizure board having seizure blocks spaced from each other along one edge of the board. The seizure board is rotatable ninety degrees (90.degree.) so that the blocks are aligned with the ports at the opposite ends of the cover when the cover and housing unit are aerial mounted or with the ports at one end of the cover to receive the cable when the housing is pedestal mounted. Different enclosure units are attached to the cover and are configured and equipped with different types of electronics depending upon the level of service and/or the technology used to control the transmission of the CATV signals in accordance with the level of service for particular subscribers. A larger enclosure unit contains interdiction electronics which is addressable by signals from the head end of the CATV system to control frequency agile oscillators which generate the signals for jamming selected premium channels. A smaller enclosure unit contains the splitting electronics and may contain band reject filter(s) which block transmission of premium channels not ordered by the subscribers. The housing in proximity to potential subscriber premises has an enclosure unit provided by a plate and the tapping circuits are terminated with loads simulating the subscriber loads. If desired a circuit board having a splitter may be located in the housing and connectors attached to the plate. External band reject filters may be mounted on the plate at the connectors. Power distribution along the cable is controlled by bypass circuits, containing an RF choke and switching means (a jumper) which is connected across a capacitor which blocks power (60 Hz AC) so that the power bypass circuit does not adversely affect the transmission of the RF CATV signals.

CATV distribution system, especially adapted for off-premises premium

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Maysville, GA, United States of America

Lamar West