JPH1065477A - Branching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply and easily conduct a repair, replacement, extension or maintenance inspection works for a branch cable branched from a trunk line cable without stopping an AC power supply fed to the trunk line cable and a high frequency signal to be transmitted at the trunk line cable being a downward stream from the branching device. SOLUTION: A 1st printed circuit board P1 to which an AC current pass circuit 21 connecting between an input port A and an output port B and a directional coupling circuit 31 connecting to the AC current pass circuit and branching the high frequency signal are integrated is mounted to a housing 11. A 2nd printed circuit board P2 to which distribution circuits 41, 42, 43 which distribute the high frequency signal distributed from the directional coupling circuit through impedance matching are mounted is mounted to a protection cover 13 covered to the housing in a way that both the printed circuit boards are separated from each other. When the protection cover is applied to the housing, the directional coupling circuit of the 1st printed circuit board and the distribution circuit of the 2nd printed circuit board are made connectable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
(Cable Television) A branching device connected to a trunk cable composed of a high-frequency coaxial cable used for a transmission system having a bidirectional communication function in a broadband network such as a system, and particularly to an AC power supply ( AC power supply) and the transmitted high-frequency signal (RF signal) in the trunk cable downstream of the branching device without power failure or interruption, and repair, replacement, extension, or maintenance of the branch cable branched from the trunk cable.・ The inspection work can be performed easily and easily.

[0002]

2. Description of the Related Art In recent broadband networks, voice,
A video and information and various services are provided. In particular, a transmission system in a fiber coaxial hybrid (HFC) type network needs to supply enough AC power to the equipment in each subscriber's home.

In this type of transmission system, when an AC current serving as an AC power supply for a relay amplifier is passed and a high-frequency signal (downstream signal: broadcast and data call signal) is transmitted, as shown in FIG. A branch device main body 10 as a branching device is connected to a trunk cable 1 made of a cable via a relay amplifier 2, and a branch terminal 1 branched into a plurality of branches (for example, four branches) in the branch main body 10 is connected to the branch line cable 1.
A, 1B, 1C, and 1D are connected, and a part of the high-frequency signal is distributed to each home via these branch cables 1A, 1B, 1C, and 1D. To send to the sender (uplink signal:
The data signal is transmitted to the trunk cable 1.

In such a conventional branching device, as shown in FIG. 5, a main cable 1 is connected between an input port A and an output port B connected to the main cable 1.
An AC current passing circuit 21 for passing an AC current supplied as a low-pass filter through an inductor L1. Capacitors C1 and C2 for passing a high-frequency signal as a high-pass filter. A transformer T1 coupled and branched by an inductive action; further, an up signal arriving from each of the branch terminals Q1, Q2, Q3 and Q4 through each circuit element is connected to a resistor R1 and a compensating capacitor C
3 and a directional coupling circuit 31 that is coupled in parallel to the input port A by mutual induction via the coupling transformer T2. An auto-transformer T3 that matches the impedance of the directional coupling circuit 31 and efficiently transmits a high-frequency signal without reflection.
A main distribution circuit 41 for dividing a high-frequency signal into two is provided. The main distribution circuit 41 includes a first sub-distribution circuit 42 including auto transformers T5, T7 and a resistor R3, and a second sub-distribution circuit 42 including transformers T6, T8 and a resistor R4. 2 sub-distribution circuit 43
To connect the branch cable 1A, 1B, 1
Four branch terminals Q1, Q2, Q to which C and 1D can be connected
3 and Q4.

That is, the configuration of this bidirectional branch circuit is such that when an upstream signal is applied to the branch terminal Q1 (the same applies to other branch terminals), a transformer T7 with a center tap, a resistor R3 and a transformer with a center tap are provided. The signal passes through the bridge circuit formed by the branch terminals Q1 and Q2 serving as the load-side impedance of T7 and is applied to the impedance matching transformer T5 (in this case, the upstream signal applied to the branch terminal Q1 is branched due to the nature of the bridge circuit. It does not appear at terminal Q2).

The upstream signal passing through the transformer T5 passes through a bridge circuit formed by a center-tapped transformer T4, a resistor R2, and impedance-matching transformers T5 and T6 which are load-side impedances of the center-tapped transformer T4. Pass through the impedance matching transformer T3 (also in this case, the upstream signal does not appear on the transformer T6 due to the nature of the bridge circuit as described above).

As described above, the upstream signal passing through the transformer T3 passes through the primary winding n1 of the coupling transformer T2, the resistor R1, and the capacitor C3, and is applied to the secondary winding n2 of the transformer T2 by mutual induction. The data is induced, passes through the high-frequency signal passing capacitor C1, reaches the input port A, and passes through the trunk cable 1, whereby data at the subscriber's house is transmitted to the transmitting side. .

[0008]

However, in the branching device having the conventional structure as described above, the alternating current passage circuit 21, the directional coupling circuit 31, and the distribution circuits 41, 4 are provided.
A bidirectional branch circuit composed of two, 43 is mounted on a single printed circuit board P and housed in a housing (not shown).
Is attached to the back side of a protective cover (not shown) covering the housing, so that the branch cable 1A, 1B,
When the protective cover is removed from the housing during repair, replacement and extension work of 1C and 1D, or maintenance / inspection work, the printed circuit board P is also removed, so that the AC power (AC power) transmitted from the trunk cable 1 and the high frequency There is a problem that the power supply and transmission of the signal (RF signal) are interrupted, thereby interrupting the power supply and transmission from the branch device to the downstream subscriber.

[0009] Conventionally, in order to solve the problems caused by such a power failure or wave interruption, a leaf spring made of phosphor bronze or the like is provided between the input port and the output port in the housing, and the leaf spring is attached to the housing. The protective cover is elastically deformed by the pressing action in the covered state, so that the connection between the input port and the output port is maintained in a disconnected state. There is a configuration in which a connection is made between an input port and an output port by using a restoring force by opening a resiliently deformed state of a leaf spring by removing a protective cover during inspection work. In addition to requiring a large spring force as a spring material, its restoring force is likely to deteriorate due to long-term elastic deformation,
Poor contact between the input and output ports is likely to occur,
There is a problem that the durability is poor.

An object of the present invention is to provide a branch cable branched from a main cable without causing an AC power supplied to the main cable and a transmitted high-frequency signal to be interrupted or stopped in a trunk cable downstream of the branching device. It is an object of the present invention to provide a branching device that can easily and easily perform repair, replacement and extension work, or maintenance and inspection work.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a housing having an input port and an output port connected to a trunk cable composed of a coaxial cable, and a rear surface of the housing which can be detached. A protection board to cover, and a printed circuit board in which a bidirectional branch circuit housed in the housing is incorporated, wherein the bidirectional branch circuit is connected between the input port and the output port. An AC current passing circuit that passes an AC current serving as an AC power supply for a relay amplifier that is supplied to the trunk cable, a down signal coupling circuit that couples and branches a part of a transmitted high-frequency signal by mutual induction, A downstream signal distribution circuit for distributing the branched downstream signal to a plurality of branch terminals, and an upstream signal to be sent from any branch terminal to the transmission side to the trunk cable. An upstream signal coupling circuit coupled by mutual induction and transmitting an upstream signal to the trunk cable, and the directional coupling circuit is formed by the downstream signal coupling circuit and the upstream signal coupling circuit, while the printed circuit board is formed. A first printed circuit board mounted on the housing side incorporating the alternating current passage circuit and the directional coupling circuit, and a second printed circuit board mounted on the back side of the protective cover incorporating the distribution circuit. Separated from each other, and in a state where the housing is covered with the protective cover, an AC current passing circuit and a directional coupling circuit of the first printed circuit board can be connected to a distribution circuit of the second printed circuit board. It is what it was.

In this case, the mutual input / output contacts of the directional coupling circuit in the first printed circuit board and the distribution circuit in the second printed circuit board are in point contact with the leaf spring due to the elasticity of the leaf spring. And a combination of the pins.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings shown in FIGS.
In the illustrated embodiment according to the present invention, FIG.
Portions having the same configuration as the conventional branching device shown in FIG. 5 will be described using the same reference numerals.

As shown in FIGS. 1 and 2, a branching device main body 10 as a branching device according to the present invention has a trunk cable 1 as shown in FIG.
And a metal housing 11 having an input port A and an output port B connected to the housing 11; a rear surface of the housing 11 being water-tightly covered via a rubber packing 12A and electromagnetically shielded via a metal mesh packing 12B. The protective cover 13 is detachably attached to the housing 11 by first attaching screws 14.

A first printed circuit board P1 and a second printed circuit board P2 are housed in the housing 11, and the first printed circuit board P1 is housed in the housing 1.
The second printed circuit board P2 is attached to the lower half of the rear surface of the protective cover 13 by third attachment screws 16 while being attached to the upper half of the first cover 1 with the second attachment screws 15. Mounted and separable.

Further, the first printed circuit board P1 includes:
An input / output port female connector 17B is provided to be fitted to the input / output port male connector 17A attached to the upper half side of the housing 11, and these male and female connectors 17A and 17B are connected to each other. As a result, the AC current passing circuit 21 and the directional coupling circuit 31, which will be described later, incorporated in the first printed circuit board P1 are connected between the input port A and the output port B.

As shown in FIG. 3, the first printed circuit board P1 includes an AC current passing circuit 21 including an AC current passing inductor L1, high frequency signal passing capacitors C1 and C2, and a downstream signal branching transformer T1. , Upstream signal coupling transformer T2, resistor R1, compensation capacitor C
3 is incorporated in the second printed circuit board P2, the high-frequency signal branched by the directional coupling circuit 31 is transmitted to a transformer T4 with a center tap, a resistor R2, and an autotransformer T5. , T6
A main distribution circuit 41 composed of an auto-transformer T3 for efficiently transmitting impedance-matched with a bridge circuit formed by the above-mentioned circuit, and an auto-transformer T5 for dividing one high-frequency signal into two by the main distribution circuit 41. A first sub-distribution circuit 42 composed of a center-tapped transformer T7 and a resistor R3, an auto-transformer T6 for dividing the other high-frequency signal divided into two by the main distribution circuit 41 into two, a center-tapped transformer T8 and a resistor R4. The second sub-distribution circuit 43 is incorporated, and the AC current passing circuit 21, the directional coupling circuit 31, and the distribution circuit 4
Branch cables 1A, 1B, 1C, 1 at 1, 42, 43
Four branch terminals Q1, Q2, Q3, Q4 to which D can be connected
To form a bidirectional branch circuit.

In this case, the directional coupling circuit 31 in the first printed circuit board P1 and the distribution circuits 41, 42, 43 in the second printed circuit board P2 include the leaf springs 18, 18, and the leaf springs 18, , 18 are configured to be connected to each other by a contact formed of a combination of pins 19, 19 which are in point contact with each other by the elasticity of the first printed circuit board P1. It is connected to the housing 11 via the mounting screw 15, and the ground point in the second printed circuit board P 2 is connected to the protective cover 13 via the third mounting screw 16.

That is, according to the present invention, by employing the above configuration, an AC current passing circuit 21 connected between the input port A and the output port B, and a high frequency A first printed circuit board P1 incorporating a directional coupling circuit 31 for branching or coupling a signal is impedance-matched to an upstream signal to be branched or coupled by the directional coupling circuit 31, and a high-frequency signal is efficiently transmitted. The second printed circuit board P2 incorporating the distribution circuits 41, 42, 43 for distributing is separated from each other, and the first printed circuit board P1 is mounted on the housing 11 side, while the second printed circuit board P2 is mounted.
2 is attached to the back side of the protective cover 13 covered by the housing 11, and the directional coupling circuit 31 of the first printed circuit board P1 and the second printed circuit board in a state where the protective cover 13 is covered by the housing 11. Since the distribution circuits 41, 42, 43 of P2 can be connected, the connection between the first printed circuit board P1 and the second printed circuit board P2 is released even if the protective cover 13 is removed from the housing 11. By itself, the AC power supply (AC power supply) supplied from the trunk cable 1 and the transmitted high-frequency signal (RF signal) are not interrupted or interrupted, so that the branching device is transferred to the downstream subscriber's house. Power supply and transmission are not interrupted.

In the above embodiment, a four-branch device has been described as an example of a branching device. However, the present invention can be applied to a two-branch device or an eight-branch device.

[0021]

As is apparent from the above description, the present invention relates to an AC current passing circuit connected between an input port and an output port, and a branch or high frequency signal connected to the AC current passing circuit. A first printed circuit board in which the directional coupling circuit to be coupled is mounted is mounted on the housing side, and a high-frequency signal branched from the directional coupling circuit is distributed to the protective cover side covered by the housing with impedance matching. Attach the second printed circuit board in which the circuit is incorporated, separate both printed circuit boards from each other, and in a state where the protective cover is covered on the housing,
Since the directional coupling circuit of the first printed circuit board and the distribution circuit of the second printed circuit board can be connected, even if the protective cover is removed from the housing, the first printed circuit board and the second printed circuit board can be connected to each other. , The AC power supply (AC power supply) supplied to the main cable and the transmitted high-frequency signal (RF signal) are not interrupted or stopped. Since the power supply and transmission to the side subscriber's house are not interrupted, repair, replacement and extension work of the branch cable branched from the trunk cable, or maintenance / inspection work can be performed simply and easily.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing one embodiment of a branching device according to the present invention as viewed from the rear side.

FIG. 2 is a cross-sectional view taken along a line XX in FIG.

FIG. 3 is an explanatory diagram showing a state in which a bidirectional branch circuit is mounted on a printed circuit board.

FIG. 4 is an explanatory diagram showing a wiring state of the transmission system.

FIG. 5 is an explanatory diagram showing a principle circuit diagram of one printed circuit board of a bidirectional branch circuit in a conventional branch device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... High-frequency coaxial cable (main cable), 1A-1D ... Branch cable, 2 ... Relay amplifier, 10 ... Branch body, 11 ... Housing, 12A ... Rubber packing, 12B ... metal net packing, 13 ... protective cover, 14 ... first mounting screw, 15 ... second mounting screw, 16 ... third mounting screw, 17A ... input / output Male connector for port, 17B female connector for input / output port, 18, 18 leaf spring (contact), 19, 19 pin (contact), P1 first printed circuit board, 21 ... AC current passing circuit, 31 ... Directional coupling circuit, P2 ... Second printed circuit board, 41 ... Main distribution circuit, 42,43 ... Sub distribution circuit, A ... Input Port, B ... output port, Q1-Q4 ...岐端Ko, a single printed circuit board P ··· conventional method.

Claims (2)

[Claims] 1. A housing having an input port and an output port connected to a main cable consisting of a coaxial cable;
A protective cover for detachably covering a rear surface of the housing; and a printed circuit board having a bidirectional branch circuit housed in the housing, wherein the bidirectional branch circuit includes the input port and the output port. An AC current passing circuit that passes an AC current serving as an AC power source for a relay amplifier that is supplied to the trunk cable connected between the port and the main cable, and a part of the transmitted high-frequency signal is coupled by mutual induction. A downstream signal coupling circuit that branches, a downstream signal distribution circuit that distributes the branched downstream signal to a plurality of branch terminals, and an upstream signal sent from any branch terminal to the transmission side is coupled to the trunk cable by a mutual induction action, and An uplink signal coupling circuit for transmitting an uplink signal to the trunk cable, wherein the downlink signal coupling circuit and the uplink signal coupling circuit form a directional coupling circuit. Meanwhile, the printed circuit board includes a first printed circuit board mounted on the housing side incorporating the AC current passing circuit and the directional coupling circuit, and a first printed circuit board mounted on the back side of the protective cover incorporating the distribution circuit. And an AC current passing circuit and a directional coupling circuit of the first printed circuit board and a distribution circuit of the second printed circuit board when the housing is covered with a protective cover. A branching device characterized by being connectable. 2. An input / output contact between a directional coupling circuit in a first printed circuit board and a distribution circuit in a second printed circuit board is made up of a leaf spring and a pin which makes point contact due to the elasticity of the leaf spring. The branching device according to claim 1, comprising a combination of the following.