JPH09102760A - Disaster-proof cable TV power supply method - Google Patents

Abstract

[PROBLEMS] To provide a method for supplying power to a relay device such as a relay amplifier, which has higher reliability and can be used even in the event of a disaster, in a transmission path of a cable television. SOLUTION: In a transmission path of a cable television, power transmission is performed by using an optical fiber metal composite cable 43 from a head end 41 of a broadcasting station to a first node 42.
At the node 42, power is supplied to the first node 42 and the relay device 44 such as each subsequent relay amplifier connected to the first node 42 via the transformer 46.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of supplying power to a relay amplifier or the like in a cable television transmission line.

[0002]

2. Description of the Related Art Conventional cable television transmission lines consist of coaxial cables and relay amplifiers, and the number of amplifier connection stages is 10 to 15, and some facilities have more than 20 stages. In order to operate this relay amplifier, the power supply is transmitted in the lower direction through the switch circuit in the relay amplifier at the upper side of the signal flow. Further, since this power supply device is provided for every 10 relay amplifiers, the power supply device is often distributed over a large number of areas, and the commercial power supply paths are often different.

FIG. 3 shows a signal transmission line of this cable television. In FIG. 3, the relay amplifiers 1 to 28 are connected to the coaxial cable connected to the head end, and the relay amplifiers 1, 13 and 24 are connected to the power supply 3 respectively.
1, 32, 33 are connected to each of these relay amplifiers 1,
Power is superposed on the coaxial cable and supplied to the relay amplifiers 13 and 24 and the relay amplifiers branched therefrom. No power supply is superposed between the relay amplifiers 1, 13, and 24.

[0004]

However, although the television signal flows in the direction from the amplifier 1 to the amplifier 28 in FIG. 3, when the commercial power in one area is cut off, the power supply in that area, for example, the power supply is supplied. The power from 32 is lost, the relay amplifier that has been receiving power from the power supply becomes inoperative, the lower transmission lines after the relay amplifier 13 do not work, and no signal can be sent.

Also, in the new CATV transmission line having a bidirectional function for servicing multimedia, a "optical coaxial hybrid system" is adopted in which several 500 terminals or less are regarded as one unit and the head end to the unit are directly connected by using an optical fiber. It's starting. FIG. 4 shows this system, in which the headend 4
A high frequency signal for television is sent as an optical signal from 1 to the first node 42 through the optical fiber cable 43, converted into an electrical signal at the first node 42, and transmitted to the relay amplifier 44 described below. A power supply 45 for supplying power to the first node 42 and a large number of relay amplifiers 44 connected to the first node 42 is installed in the first node 42, and when the area where the power supply 45 is installed loses power. , All terminals of this unit are stopped.

Moreover, the transmission line of the cable television is provided by a method of suspending a coaxial cable or an optical fiber with a messenger wire as a support line, but the height of this messenger wire is about 6 m above the ground, and by any chance it is a support pillar. Even if it falls down, this messenger wire often serves as a support to prevent complete collapse, making it a mechanically stronger facility than the distribution line above it. Therefore, the probability that the transmission line of the cable TV will be cut even if the distribution line is cut due to an earthquake or a power failure occurs. If power is being sent to the power supply by another method, the transmission path of the cable TV is alive,
The terminal may be able to receive TV.

An object of the present invention is thus to provide a method of supplying power to a relay device such as a relay amplifier which is more reliable and can be used even in the event of a disaster in a transmission path of a cable television.

[0008]

According to a first aspect of the present invention, in a transmission path of a cable television, power is transmitted from the head end of a broadcasting station to the first node by an optical fiber metal composite cable, and the power is transmitted from the head end. A disaster-proof type cable television power feeding method is provided in which power is supplied to a first node and relay devices such as each subsequent relay amplifier connected to the first node via a transformer at a node location.

The power sent from the headend is dropped to an appropriate voltage via a transformer and supplied to the first node and a relay amplifier connected to the first node. An optical fiber metal composite cable is used from this head end to the transformer of the first node, and power is transmitted by the cable. At that time, the voltage is low-current transmission in order to reduce the loss on the wire. In addition, from the first node to the relay amplifier, it is placed on a coaxial cable and sent. Also, the television signal is an optical signal from the head end to the first node, and is converted into an electrical signal at the node. Further, the relay device includes a trunk line branch amplifier, an extension amplifier, a tap-off, and the like.

According to a second aspect of the present invention, in the transmission path of the cable television, power is transmitted by superimposing the coaxial cable from the head end of the broadcasting station to the first relay amplifier to transmit the power.
A disaster-proof type cable television power feeding method in which power is supplied to the first relay amplifier and each subsequent relay amplifier connected thereto through a transformer at the relay amplifier location.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the present invention. As in the system of FIG. 4, a high frequency signal for television is sent from the head end 41 to the first node 42 by an optical fiber cable 43. Single-phase AC 200 V is transmitted from the head end 41 along the optical fiber cable 43. A transformer 46 is provided in front of the first node 42, the transmission voltage is reduced to 60V by the transformer 46, and the first node 42 and a large number of subsequent relay amplifiers 44 connected thereto are superposed on the coaxial cable. To supply the 60V power.

FIG. 2 shows a second embodiment of the present invention. In this embodiment, instead of the transformer 46 in the first embodiment, a stabilized power supply CVC is provided.
F47 is provided. In this case, three-phase AC200V is transmitted from the head end, and the CVCF47 transmits 60V of this.
The voltage is reduced to V and power is supplied to the first node 42 and the relay amplifier 44 connected thereto. At that time, a battery is provided in the CVCF 47, and when the power supply from the head end 41 fails, the first node 42 and the relay amplifier 4 are fed from this battery.
4 is to be supplied with power. In some cases, DC power may be transmitted to the first node 42 and the relay amplifier 44.

Further, from the head end 41 to the transformer 46
To supply electric power to the CVCF 47 or the like, a power cable can be provided along the optical fiber cable 43, or a composite cable including the optical fiber cable and the power cable can be provided.

The present invention is not limited to the above-mentioned embodiment, but power is supplied from the head end to the first node, the main branch amplifier, the extension amplifier, the tap-off, etc. Further, in the above-described embodiment, a new CATV transmission line system using an optical cable has been described, but this is also true in the conventional transmission line along the coaxial cable-communication line from the head end of the broadcasting station to the first relay amplifier. A method of performing low current transmission and supplying power to the first relay amplifier and each subsequent relay amplifier connected thereto via a transformer at the first relay amplifier location is also included.

[0015]

According to the first and second aspects of the present invention, power is supplied from the head end of the broadcasting station to the first node and the relay device connected to the first node. Even if there is a power outage due to a disaster, the terminal TV receiver can still receive it as long as the cable TV transmission line is alive. Further, by transmitting power from the head end in this way, it is possible to centrally monitor the system function of the transmission line.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a transmission line according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a transmission line according to a second embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a transmission path of a conventional cable television.

FIG. 4 is a schematic configuration diagram of a transmission path of a conventional new type cable television.

[Explanation of symbols]

41 head end 42 node 43 optical fiber cable 44 relay amplifier 46 transformer 47 stabilized power supply CVCF

Claims (2)

[Claims] 1. In a transmission path of a cable television, power is transmitted using an optical fiber metal composite cable from a head end of a broadcasting station to a first node, and power is supplied to the first node and a power source via a transformer at the first node location. A disaster-proof type cable television power feeding method, characterized in that the power is supplied to a relay device such as each subsequent relay amplifier connected to it. 2. In a transmission path of a cable television, power is transmitted by superimposing it on a coaxial cable from a head end of a broadcasting station to a first relay amplifier, and power is supplied to the first relay amplifier via a transformer at the first relay amplifier location. A disaster-proof type cable television power feeding method, characterized in that the power is supplied to a relay amplifier and each relay device connected to the relay amplifier.