JPH0220757Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a television communal listening terminal used in a television communal listening system.

[Background technology]

Conventionally, when a high-frequency signal is received via a distributor in a television community reception device, a community terminal is used to relay a coaxial cable serving as a signal line between indoors and outdoors. FIG. 1 shows an example of its configuration, in which 1 is a television antenna, 2 is a coaxial cable, 3 is a distributor, 4 is a public listening terminal, and 6 is a television receiver. Note that the signal is distributed from the distributor 3 using two coaxial cables 2. A television receiver 6 is connected to the end of the coaxial cable 2 from the distributor 3.
A public listening terminal 4 for connection with a coaxial cable 2 from the terminal is connected. In this configuration, a signal from a television antenna 1 is transmitted to a television receiver 6 via a coaxial cable 2, a distributor 3, and a common listening terminal 4. On the other hand, the television receiver 6 is not connected to the common listening terminal 4 which is connected to the other output terminal of the distributor 3 via the coaxial cable 2. If a so-called terminating resistor is not connected to the output side of this common listening terminal 4, the signal from the television antenna 1 will be reflected between this common listening terminal 4 and other components,
This reflected wave is transmitted to the television receiver 6 and appears on the television receiver 6 as a ghost. Therefore, a dummy connection lid 5 provided with a terminating resistor inside is connected to the output terminal of the common listening terminal 4 to eliminate reflections occurring at the common listening terminal 4 and to prevent ghosting of the television receiver 6.

FIG. 2 shows a perspective view of the common listening terminal 4 and the dummy connection lid 5. On the top surface of the body 8 made of an insulating material of the common listening terminal 4, a coaxial cable 2 from a television receiver 6 is connected. A signal output terminal 9 and an output terminal ground section 12 are provided. 10 is a connection hole for a terminating resistor, and 11 is an internal conductor connection hole for the coaxial cable 2. 13 is a fixing screw for fixing the ohmic band 12a, and 14 is an input terminal ground portion.
The dummy connection lid 5 is formed into a box shape with an open bottom, and is designed to cover the top of the common listening terminal 4.

FIG. 3 shows an exploded perspective view of the dummy connection lid 5,
Reference numeral 7 denotes a box-shaped lid with an opening at the bottom, 15 a fixed shaft that supports the resistance support 17 that protrudes downward from the inside of the lid 7, and 16 a coiled fixed spring that elastically fixes the resistance support 17. , 18 are terminating resistors, and fixed pieces 17a, 1 are integrally formed on the resistor support base 17.
It is clamped and fixed by 7b. 19 is resistance 18
20 is the ground side connection terminal of the resistor 18. 21 is a fixing hole into which the fixed shaft 15 is inserted. In FIG. 3, the fixed shaft 15 passes through the fixing hole 21 of the resistance support 17, and the resistance support 1
7 is prevented from coming off the fixed shaft 15. Two fixing springs 16 are interposed between the resistance support base 17 and the lid 7, and the angle of the resistance support base 17 can be changed around the fixation hole 21. When the dummy connection lid 5 is connected to the common listening terminal 4 as shown in FIG. 2, the signal line side connection terminal 19 of the resistor 18 is inserted into the connection hole 10, and the coaxial cable 2
make a contact connection with the internal conductor of the Further, the ground side connecting terminal 20 of the resistor 18 is connected to the fixing screw 13 in contact.
As described above, when the dummy connection lid 5 is connected to the common listening terminal 4, the output terminal of the common listening terminal 4 is terminated with 75Ω, which is the value of the resistor 18. However, the dummy resistor in the structure of the dummy connection lid 5 has extremely poor high frequency characteristics. That is, 75Ω
VSWR with characteristic impedance shows a large value. Therefore, the result is that the effects of ghost reduction and the like are not very effective for the television receiver 6.

[Purpose of invention]

The present invention has been proposed in view of the above-mentioned points.
The purpose of this is to provide a terminal for common television viewing that improves VSWR characteristics and reduces ghosting.

[Disclosure of the invention] Hereinafter, one embodiment of the invention will be described in detail with reference to the drawings. FIG. 4 shows a perspective view of the resistance support stand 17, etc. of the dummy connection lid 5. A cylindrical body 22 is a metal plate for covering the outer periphery of the resistor 18, and the cylindrical body 22 is made of a conductive thin plate. The cylindrical body 22 is inserted into the resistance support base 17 so as to enclose the resistor 18 inside, and important points of the cylindrical body 22 and the ground side connection terminal 20 of the resistor 18 are connected to ground the cylindrical body 22. .

FIG. 5 shows another embodiment, in which the upper part forms a cylindrical body 22a and the lower part forms a metal plate consisting of a rectangular thin metal plate, as shown in FIG. 5b. , the cylindrical body 22a is inserted so as to enclose the resistor 8 therein, and the resistor support base 17 is placed thereon. The ground side connection terminal 20 of the resistor 18 is connected to a metal plate, and the metal plate is connected to the fixing screw 1 of the common listening terminal 4.
Contact connection to 3.

In FIG. 6, the outer periphery of the resistor 18 is covered with a metal tape 23, which is a metal plate, and this metal tape 23 is connected to the ground side connection terminal 20 of the resistor 18.

FIG. 7 is a comparison graph of the VSWR frequency characteristics of the conventional dummy connection lid 5 and the dummy connection lid 5 according to the embodiment of the present invention. As shown in Figure 7, by covering the outer periphery of the resistor with a metal plate, the VSWR can be improved.
This has been greatly improved and the ghosting of the television receiver 6 can be reduced.

[Effect of idea]

As mentioned above, this invention covers the outer periphery of the termination resistor with a grounded conductive metal plate, which reduces the stray capacitance of the termination resistor and improves the high frequency characteristics of the termination resistor. This allows for better impedance matching at the termination.
It is possible to improve VSWR and reduce reflected waves,
Therefore, there is an advantage that ghosts in the television receiver can be effectively prevented.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a television community reception system, Fig. 2 is a perspective view of a conventional common listening terminal and a dummy connection lid 5, Fig. 3 is an exploded perspective view of the dummy connection lid 5, and Fig. 4a. , b is a perspective view of an embodiment of the present invention,
Figures 5a and 5b are perspective views of other embodiments same as above;
The figure is a perspective view of still another embodiment of the same as above, and FIG. 7 is a VSWR characteristic diagram of the same as above. 1... TV antenna, 2... Coaxial cable,
3...distributor, 4...common terminal, 6...television receiver, 18...terminal resistor.

Claims (1)

[Scope of claim for utility model registration] (1) The received signal from the television antenna is distributed by a distributor, and a common listening terminal is connected between the end of each signal line connected to the distributor and the television receiver. In such a TV common listening terminal, a grounded conductive metal plate is covered around the outer periphery of a terminating resistor that is connected to the common listening terminal when a television receiver is not connected to the common listening terminal. A terminal for common television viewing featuring the following. (2) Utility Model Registration In the television common listening terminal described in claim 1, the metal plate is formed of a metal tape, the metal tape is covered around the resistor, and the ground side of the resistor is connected. The one connected to the terminal.