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METHOD FOR SIGNAL REDUNDANCY IN TRADITIONAL HYBRID FIBER COAXIAL (HFC) PLANT CONVERTED TO DEEP FIBER HFC PLANT

IP.com Disclosure Number: IPCOM000200537D
Publication Date: 2010-Oct-18
Document File: 3 page(s) / 119K

Publishing Venue

The IP.com Prior Art Database

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This is the abbreviated version, containing approximately 52% of the total text.

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M E T H O D F O R S I G N A L R E D U N D A N C Y I N T R A D I T I O N A L H Y B R I D F I B E R C O A X I A L ( H F C ) P L A N T C O N V E R T E D T O D E E P F I B E R H F C P L A N T


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Authors: David Urban and Jorge Salinger

This paper describes a method for signal redundancy as a traditional hybrid fiber coaxial (HFC) plant is converted to a deep fiber HFC plant. As service groups are reduced to increase narrowcast capacity for video on demand (VOD), switched digital video (SDV), StartOver (SO), High Speed Data (HSD), Internet Protocol Television (IPTV), and Voice over Internet Protocol (VoIP) services, amplifiers are converted to fiber nodes. The new fiber nodes may still require the power feed over coax. The coax to the deep fiber nodes may also carry backup upstream (US) and downstream (DS) signals. The backup signals may be used, for example, if 1) the fiber optic feed is cut, 2) the optical transmitter or receiver at the fiber node or headend fails.

Figure 1 depicts how signal redundancy may be handled in a traditional HFC plant which has been converted to a deep fiber HFC plant.

Fiber Node

Optical Coax

Coax

Power

DS

DS

Optical fiber

Optical fiber

US

US

Power Supply

Amp

Amp

to deep fiber HFC

Coax

Coax Coax

US Primary

US

DS Primary

Coax

Coax

Power

Back up

DS

Fiber Node 2 Optical Coax

Power Supply

Fiber Node 1

Optical Coax

Coax

Figure 1: Method for signal redundancy in traditional HFC plant converted to deep fiber HFC plant.

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Figure 2 shows how the proposed method can be used in a system containing coax and optical fiber. It should be noted that the upstream RF signals may need to be switched off when the primary signals are used so as not to add noise to the feeding fiber node.

Amp

Primary coax

Input optical fiber

DS

 Diode detector

    DS 54-1000 MHz

DS Switch Logic & control

48 vac

  60 Hz
squarewave
Back up

54-1000 MHz

Power Supply

H

Coax

L

H

coaxial to amps

US 5-42 MHz from CMS & STBs

L

 Back up 5-42 MHz

48 vac

  60 Hz squarewave

Amp

US Switch Logic & contro...