JPH0530376A - Common reception system - Google Patents

Abstract

PURPOSE:To prevent a branching characteristic from being disturbed depending on the presence of a use of a reception terminal equipment. CONSTITUTION:When a cover 11 is closed and a reception terminal equipment 10 is not in use, a center conductor 12B of an F type coaxial connector 12 is connected to ground via a dummy resistor 14 and a microswitch 15 to bring the termination impedance of a coaxial cable CV in the matching state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint reception system for jointly receiving TV radio waves and FM radio waves and distributing the jointly received radio waves to a plurality of residents in an apartment house or a multipurpose building. It is about.

[0002]

2. Description of the Related Art In a common building built in the city or in the case of a common house, a common antenna, a mixer, a booster, etc. are provided on the roof of the building, and the radio waves received by the common receiver are provided to each resident. A joint reception system for distribution is adopted. FIG. 4 shows an outline of such a joint reception system, in which a television antenna placed on the roof of a building,
The radio waves received by the (VHF, UHF) FM antenna and the satellite broadcast receiving antenna (BS) are collected in the mixer MIX that also serves as a booster.

Then, it is supplied to the distributors D _{1 to} D ₆ arranged on each floor in the building through the coaxial cable C.
Each of the distributors D _{1 to} D ₆ is provided with a demultiplexing circuit that distributes received radio waves to residents on each floor, and the demultiplexed signals are placed in the room where each viewer is through a television coaxial cable. It is adapted to be supplied to the receiving terminal C which is being operated.

For example, for a resident on the 6th floor, the mixer M
IX via the distributor D ₆ to three receiving terminals C ₆₁ ,
It is distributed to C ₆₂ and C ₆₃ . Similarly, for the occupants on the first floor, the reception radio waves are supplied from the mixer MIX to the distributor D _1, and the viewers on the first floor receive four receiving terminals C ₁₁ , C ₁₂ ,
Received radio waves are supplied to C ₁₃ and C ₁₄ . In this case, a boost amplifier may be inserted in the middle of a floor located far away.

[0005]

By the way, in the joint reception system as described above, it is preferable that the receivers on each floor connect the cable connectors to their own receiving terminals C and are always in a receiving state. When the coaxial cable is not connected to the receiving terminal C, that is, when the receiving terminal is opened, impedance mismatch occurs at this point.

For example, when the receiving terminal C ₁₁ on the first floor is in an open state, a standing wave is generated in the cable supplying the signal to the receiving terminal C ₁₁ , and this signal is demultiplexed by the distributor D ₁ . Impairing the characteristics deteriorates the signal characteristics of other receiving terminals on the first floor. Further, if such a receiving terminal is opened at each place, the transmission characteristic of the entire joint receiving apparatus is deteriorated, and particularly in the case of a TV receiver, the resolution is deteriorated and the image quality such as ghost and smear is deteriorated. There was a problem.

[0007]

The present invention has been made to solve the above problems, and one or more broadcast waves are received by a common receiving device, and a plurality of broadcast waves are received by a coaxial cable. In the joint receiving device to be distributed to the receiver, a dummy resistor corresponding to the transmission impedance of the coaxial cable is connected to the receiving terminal arranged near the receiver, and the cable of the receiver is connected to the receiving terminal. When not present, the terminal of the coaxial cable is short-circuited by the dummy resistor to construct a joint reception system.

[0008]

Since the terminating impedance of the receiving terminal disposed on each floor can always be made to match the transmission impedance of the coaxial cable, the VSWR of the coaxial cable laid indoors becomes small, which is excellent. Image quality can be obtained.

[0009]

1 is a partial sectional view of a receiving terminal C of a joint receiving system according to the present invention, in which a receiving box 10 is embedded in a wall surface shaded with diagonal lines. Reference numeral 11 denotes a lid of the receiving box 10, which in this example can be opened by a hinge 10A. One end of a coaxial cable CV drawn out from the distributor D is laid on the bottom surface of the reception box 10, and a TV terminal (F-type coaxial connector) 12 is connected to the coaxial cable CV. As is well known, this F-type coaxial connector has an insulator 12A placed in an outer conductor ring, and a center conductor piece 12B into which a connector pin is inserted is arranged at the center thereof. Then, the other coaxial cable CV to be connected as shown by the dotted line is inserted with the lid 11 opened, so that the antenna reception output for co-viewing can be supplied to the TV receiver and the FM receiver. it can.

In the joint reception system of the present invention, the receiving terminal is provided with a dummy resistor 14 (75Ω), and this dummy resistor is configured to short-circuit the end of the coaxial cable when the lid is closed. There is. That is,
One end of the dummy resistor 14 is connected to one end of the central conductor piece 12A, and the other end thereof is connected to the micro switch 15. The micro switch 15 is used for the lid 11.
Is formed to be grounded when closed.
Therefore, in the case of the joint reception system including such a receiving terminal, the coaxial cable is left open even when the cable is not connected to the terminal, that is, even when the lid 11 is closed. However, the entire system is always matched by the transmission impedance, and the VSWR is not deteriorated by the standing wave generated in the coaxial cable in the building.

FIG. 2 shows another embodiment used in the receiving terminal of the common receiving system of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals. In the case of this embodiment, an F plug connector 16 for dummy is provided inside the lid body 11, one end of the dummy resistor 14 is connected to the center conductor of this F plug connector 16, and the other end is connected to the receiving box 1
Connected to 0 ground. Therefore, when the cable is not connected to the receiving terminal, that is, as shown in FIG.
Is closed, the TV terminal 12 is the F plug connector 1
It is short-circuited by the dummy resistor 14 via 6 and does not become an open state. Also, by opening the lid 11, the dummy resistor 1
4 is excluded, TV receiver from the direction shown by the arrow, or F
The input cable CV of the M receiver can be connected.

FIGS. 3A and 3B show another embodiment of the receiving terminal, which is an F type coaxial connector applicable when the receiving box is open type. In this figure,
Reference numeral 20 denotes a connector body in which a screw 20A is formed on the outer circumference and two streak grooves 20B are formed in the longitudinal direction.
Reference numeral 1 is an insulator, and 22 is a central conductor piece arranged at the center of the insulator 21. The central conductor piece penetrates the inside and is electrically connected to the central conductor connecting piece 24A. Further, the end of the TV coaxial cable CV wired by the joint reception device is connected to the center conductor connecting piece 24A and the ground piece 24B.

Reference numeral 25 denotes an elastic piece arranged in the concave groove 20B. The elastic piece 25 is held in the concave groove 20B by an insulator 26 so as not to come into contact with the connector body 20. Although the tip of the elastic piece 25 is covered with the insulator 27, the elastic piece 25 and the flange 23 are X-shaped because the elastic piece 25 is biased in the outer peripheral direction.
Always in electrical contact at a point. Therefore, the rear end connecting piece 25A of the elastic piece 25 is at the ground potential. 28 is a dummy resistor (75Ω) soldered between the rear end connecting piece 25A and the center conductor connecting piece 24A.
Indicates. In this F-type coaxial connector, since the elastic piece 25 and the flange 23 are normally in contact with each other at the point X, the center conductor and the ground are short-circuited by the dummy resistor 28.

However, when the flange of this F-type coaxial connector is fixed in the receiving box and the F-plug connector 30 for connection is screwed in from the front as shown in FIG. It is inserted into the central conductor piece 22 and a coaxial connection is made. Then, by this screwing, the insulator 27 provided at the tip of the elastic piece 25 becomes concave groove 20B.
When it sinks inside, the electrical connection point X between the elastic piece 25 and the connector body 20 separates, and the short circuit due to the dummy resistor 28 is released. Then, the reception radio wave can be supplied to the TV receiver and the FM receiver through the F plug connector 30.
Therefore, by using this F-type connector as the receiving terminal of the joint reception system, the termination of the coaxial cable for power supply arranged on each floor and each room can be always set to the matching impedance (75Ω). , VSWR (volt of each coaxial cable laid for joint reception
age standing wave ratio) can be minimized.

[0015]

As described above, the joint reception system of the present invention has a predetermined transmission impedance regardless of whether the receiving terminals installed on each floor and each room are in use or not in use. Since they are matched with each other, it is possible to prevent the television image from being disturbed by the standing ratio propagating through the laid coaxial cable, and it is possible to effectively distribute the reception radio wave from the joint reception antenna. is there.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a reception terminal device of a joint reception system of the present invention.

FIG. 2 is a sectional view showing another embodiment of the receiving terminal of the present invention.

FIG. 3 is a perspective view of an F-plug type coaxial connector in which matching conditions are always satisfied.

FIG. 4 is an explanatory diagram of a cable laying situation in a building that employs a shared reception system.

[Explanation of symbols]

 10 reception box 11 lid 12 F type coaxial connector 14 dummy resistor 15 micro switch

Claims (1)

Claim: What is claimed is: 1. A common receiving device, wherein a common receiving device receives one or more broadcast waves and distributes the broadcast waves to a plurality of receivers by a coaxial cable. Connect a dummy resistor corresponding to the transmission impedance of the coaxial cable to the receiving terminal arranged in the vicinity, and short the terminal of the coaxial cable by the dummy resistor when the receiver cable is not connected to the receiving terminal. A joint reception system characterized by being adapted.