JPH11185888A - Television plug - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower the transmission loss to television signals in a high frequency band. SOLUTION: A box-like case main body 16 opened in the cable lead-in side by being fitted in a holder 4 installed in the inner face of the base 1 is formed as a shield case 2 of a television plug comprising a case 1 and a cover 3 fitted in the base 1. An earth piece 18 whose tip is pressure-contacted with the outside coat conductive wire 14 of a coaxial cable 11 fastened and fixed in a coaxial cable fixing part 10 is extended from the open side of the case main body 16 to lower unmatching of impedance in the cable lead-in part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television plug connected to a serial unit or the like installed on a wall or the like for displaying a television signal received by a television antenna on a television receiver, and more particularly to a high frequency band such as a CS broadcast. The present invention relates to a television plug configured to reduce insertion loss for a television signal in a band.

[0002]

2. Description of the Related Art Conventionally, for example, a television plug shown in FIG. 4 is used as a television plug which is used by connecting a wall surface tap-off or the like to project a television signal received by a television antenna on a television receiver. In FIG. 4, the TV plug includes an insulating base 1, a conductive shield case 2, and an insulating cover 3. The base 1 has a center pin 6 insulated inside a cylindrical cap 5 protruding in a direction orthogonal to the drawing direction of the coaxial cable 11.
A core wire connecting portion 7 for sandwiching and connecting one core wire 12 is formed.

A conductive holder 4 is provided inside a base 1.
Is attached. The holder 4 has a core wire connecting portion 7 of the center pin 6.
And a case fitting portion 8 for fitting with the case fitting portion 17 of the shield case 2 is formed on the peripheral side surface, and the outer conductor 14 of the coaxial cable 11 is provided on the cable lead-in side. Cable fastening portions 9 and 10 for tightening and fixing are integrally formed.

[0004] The shield case 2 has a box frame shape having five case surfaces 2a, 2b, 2c, 2d, and 2e opened to the base 1 side. The case surface 2e has a cutout 2f for drawing in a cable. The case projection 17 protruding inside the case surfaces 2b and 2c is assembled to the base 1 by fitting it into the case fitting portion 8 on the side surface of the holder 4. Cover 3
Has a box frame shape that is open to the base 1 side and has a cutout 21 formed on the cable lead-in side, and is assembled by fitting to the side surface of the base 1. Normally, the shield case 2 is fixed inside the cover 3. When the cover 3 is fitted to the base 1, the shield case 2 is fitted to the holder 4.

[0005]

However, in such a conventional television plug, the recent 1G
With respect to television signals such as BS broadcasts and CS broadcasts in a broadcast band exceeding Hz, insertion loss, which was not a problem in the conventional VHF band and UHF band, becomes noticeable, and transmission loss occurs in television signals in a high frequency band. was there.

FIG. 5 is a characteristic diagram of the insertion loss with respect to the frequency of the conventional television plug of FIG. 4, and the measurement results at points A to D are as follows, for example.

[0007]

[Table 1]

In particular, in BS broadcasting and CS broadcasting, the electric field received by the antenna is greatly reduced under the influence of the weather, and the transmission loss at the television plug is added to this, so that the input level at the television receiver is reduced. There is a possibility that the quality of the received video may be reduced and the reception unreachable state may frequently occur due to a drop below the allowable level. The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide a television plug having a structure capable of suppressing transmission loss even in a high-frequency band television signal.

[0009]

In order to achieve this object, the present invention is configured as follows. First, the TV plug of the present invention includes an insulating base, a conductive shield case, and an insulating cover. Here, the base is a core wire connecting portion on the inner surface side of the base connecting the center pin insulated inside the cylindrical cap protruding in the direction orthogonal to the coaxial cable drawing direction and the core wire, and the center pin mounted on the inner surface of the base. And a conductive holder integrally formed with a cable fastening portion for tightening and fixing the outer conductor of the coaxial cable on the cable lead-in side.

The shield case is formed by bringing the shield case into contact with the holder while covering the core wire connecting portion. The present invention relates to a TV plug having such a structure.
As a shield case, an earthing piece is provided, which is extended toward the cable lead-in side and is pressed into contact with the coaxial cable jacket conductor fixed to the coaxial cable fastening portion.

As described above, the shield case is provided by extending the shield case at the portion of the outer conductor wire of the coaxial cable which is drawn in and connected to the plug, and the shield piece is provided so as to be electrically contacted, so that the plug is exposed for connection. We suppress sudden change of impedance in coaxial cable part and take matching,
By suppressing generation of a standing wave by impedance matching, insertion loss (transmission loss) in a high-frequency band exceeding 1 GHz is reduced.

[0012]

FIG. 1 is an exploded view of a television plug according to the present invention. The TV plug of the present invention includes an insulating base 1 made of synthetic resin, a conductive shield case 2 made of a metal plate or the like, and an insulating cover 3 made of the same synthetic resin as the base 1. Be composed.

The base 1 is provided with a cylindrical cap 5 in a direction perpendicular to the drawing direction of the coaxial cable 11, that is, in a direction toward the lower side in the figure, and a center pin 6 is insulated and arranged inside the cap 5. I have. The rear end of the center pin 6 protrudes into the inside of the base 1 to form a core wire connecting portion 7 divided in the axial direction. The core wire 12 of the coaxial cable 11 is connected to the core connection part 7 by sandwiching and fixing.

A conductive holder 4 is mounted inside the base 1. The holder 4 has an opening at the center thereof for taking out a core wire connecting portion 7 formed at the rear end of the center pin 6, and a case fitting portion 8 for fitting the shield case 2 in a bent portion on the side surface. ing. Further, on the side of the holder 4 where the coaxial cable 11 is pulled in, cable fastening portions 9 and 10 formed of a pair of claw members bent upward are integrally formed.

The cable fixing portions 9 and 10 tighten and fix the outer conductor 14 of the coaxial cable 11 to be electrically connected to the holder 4. The shield case 2 has a case body 16 opened to the base 1 side. The case body 16 has a box-like shape opened to the coaxial cable 11 side in a state fitted to the holder 4 on the base 1 side by the case surface 16a on the front end side, the case surfaces 16b and 16c on both sides, and the upper case surface 16d. .

The earth piece 18 extends obliquely downward from the box-shaped opening of the case body 16 on the coaxial cable 11 side, that is, from the end of the upper case surface 16d as shown in the figure. A contact piece 20 is provided at the tip of the grounding piece 18 for being electrically pressed by the outer conductor 14 of the coaxial cable 11 fastened to the cable fixing portions 9 and 10 on the base 1 side. Is formed.

The grounding piece 18 has a trapezoidal shape that is wide on the case body 16 side and narrows linearly toward the contact piece 20 for the outer conductor 14. The shield case 2 having such a structure includes the case surfaces 16b, 1 on both sides.
The fitting protrusion 17 protruded by being pressed outwardly into 6c is fitted into the case fitting portion 8 formed on the side surface of the holder 4 of the base 1 so as to be mechanically and electrically connected and fixed to the holder 4. Is done.

The shield case 2 is in contact with the holder 4 in a state where the shield case 2 covers the core wire connection portion 7, so that the periphery of the core wire connection portion 7 is shielded. The cover 3 has a notch 21 formed on the side where the coaxial cable 11 is drawn in. The cover 3 and the base 1
Is assembled. Note that the shield case 2 includes the cover 3
When the cover 3 is fitted to the base 1, the shield case 2 is fitted to the holder 4.

FIG. 2 is a sectional view of the television plug of the present invention in an assembled state. A cap 5 is taken out below the base 1 and a center pin 6 is insulated at a central portion. A holder 4 is mounted inside the base 1. Holder 4
Is electrically connected to the cap 5 at a position (not shown). The coaxial cable 11 has a core wire connecting portion 7 in which the core wire 12 projects into the base 1 of the center pin 6 in a state where the core wire 12, the inner insulator 13, and the outer conductor wire 14 are stripped as shown in the figure.
To connect.

Further, the outer conductor 14 of the coaxial cable 11 is fastened and fixed mechanically and electrically by the cable fastening portions 9 and 10. Such a base 1
And the cover 3 in which the shield case 2 is fixed from above is mounted. The shield case 2 covers a connection portion between the center pin 6 and the core wire 12 with a box-shaped portion of the case body 16 and contacts a tip of a ground piece 18 extending obliquely downward from an opening of the shield case 2 on the cable lead-in side. The piece 20 is pressed against the outer conductor 14 of the coaxial cable 11 to be electrically connected.

The formation of the grounding strip 18 realizes a function as a shield case by the grounding strip 18 even at the exposed portion of the outer conductor wire 14 of the coaxial cable 11, and changes in impedance at the TV plug connection portion of the coaxial cable 11. And impedance matching. FIG. 3 is a characteristic diagram of measurement results of insertion loss with respect to frequency of the television plug of the present invention shown in FIGS. In the characteristic diagram of FIG. 3, the following measurement results are obtained for the measurement points A to D.

[0022]

[Table 2]

The characteristics of FIG. 3 are compared with the characteristics of the conventional television plug of FIG. 5 as follows. First, at the frequency of 770 MHz at the measurement point A included in the UHF broadcast band, the transmission loss has been reduced from about 0.20 dB to about 0.10 dB and about 0.10 dB in the present invention. You. Also, the frequency of 1335 MHz at the measurement point B serving as the BS broadcast band was 0.40 dB in the past, but 0.30 dB and 0.10 dB in the present invention.
Transmission loss is improved by about dB.

The frequency of 1895 MHz at the measurement point C serving as the CS broadcasting band was 1.2 dB in the past, but is 0.40 dB and 0.8 dB in the present invention.
Transmission loss is improved. In addition, 2150 MH at measurement point D
In the case of z, which was conventionally 1.70 dB, in the present invention, the transmission loss can be improved by 0.40 dB and 1.30 dB.

As a result, by using the television plug of the present invention, the transmission loss of the television signal in the high frequency band of the BS broadcast or the CS broadcast, which is easily affected by the weather, is reduced, and the input allowable level of the television receiver is sufficiently increased. , Stable reception and reproduction of a television signal in a high-frequency band can be performed. In the above embodiment, the earth piece 18 having a trapezoidal shape extends obliquely from the opening of the shield case 2 on the cable lead-in side.
The shape of 8 may be any configuration other than the trapezoid as long as it is in contact with the outer conductor 14 of the coaxial cable 11 by changing the straight line on both sides to the tip in a curved manner. Further, on both sides of the grounding piece 18, downward case pieces similar to the case surfaces 16b and 16c of the case body 16 may be provided integrally by bending.

In the above-described embodiment, the shield case 2 has a box shape. However, the shield case 2 is not limited to the box shape. Good. For example, the side surface of the shield may be formed by extending the side surface of the holder 4 upward without forming the side surface of the shield portion by the side surfaces 16b and 16c of the shield case 2. Accordingly, the shield case 2 may have a configuration in which the shield case 2 has a shape such that the upper part of the core wire connection portion 7 is struck, and further includes a grounding piece 18 that is in contact with the outer conductor 14 of the coaxial cable 11.

The core wire connecting portion 7 does not need to be formed integrally with the center pin 6, but may be a structure in which the core wire 12 is fixed by screws or the like and connected to the center pin. Further, in the above embodiment, the grounding piece 18 is connected to the coaxial cable 11.
Although it is in direct contact with the outer conductor 14, it may be indirectly electrically connected to the outer conductor 14 by contacting the cable fastening portions 9 and 10.

[0028]

As described above, according to the present invention, as a shield case built in a television plug,
By providing an earthing piece extended to the cable lead-in side and pressed into contact with the coaxial cable jacket conductor fixed and fastened to the coaxial cable fixing portion, impedance matching at the plug connection portion of the coaxial cable is obtained by 1 MHz.
, A transmission loss in a high-frequency band exceeding the above, and a sufficient reception input level in BS broadcasting or CS broadcasting can be ensured, and a high-quality received video can be displayed.

[Brief description of the drawings]

FIG. 1 is an exploded view of a television plug of the present invention.

FIG. 2 is a sectional view of a television plug according to the present invention.

FIG. 3 is a characteristic diagram of insertion loss with respect to frequency of the television plug of the present invention.

FIG. 4 is an exploded view of a conventional TV plug.

FIG. 5 is a characteristic diagram of insertion loss with respect to frequency of a conventional TV plug.

[Explanation of symbols]

 1: Base 2: Shield case 3: Cover 4: Holder 5: Cap 6: Center pin 7: Core wire connection part 8: Case fitting part 9, 10: Cable fastening part 11: Coaxial cable 12: Core wire 13: Internal insulation Object 14: Outer conductor 15: External insulator 16: Case body 16a to 16d: Case surface 17: Fitting projection 18: Case piece 20: Contact piece 21: Notch

Claims (1)

[Claims] An insulative base, a conductive shield case and an insulative cover are provided, said base having a center pin insulated and arranged inside a cylindrical cap protruding in a direction orthogonal to a coaxial cable drawing direction. A core wire connection portion on the inner surface side of the base for connecting the coaxial cable core wire, a hole which is mounted on the inner surface of the base and through which the center pin is taken out, and further tightens and fixes the outer conductor of the coaxial cable to the cable lead-in side. A conductive plug integrally formed with a mounting portion, wherein the shield case is placed over the core wire connecting portion while being in contact with the holder to form a shield portion. The coaxial cable jacket conductor or the coaxial cable extending to the cable lead-in side and fastened and fixed to the coaxial cable fixing portion. A television plug, comprising: a ground piece that is pressed into contact with a cable fixing portion.