JPS6145646Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention provides an unbalanced signal that is inserted between the tuner input terminal of a television receiver and the end of the feeder line connected to the antenna to suppress unbalanced signals carried on the feeder line. This relates to a balanced signal suppression transformer.

Incidentally, an unbalanced signal occurs when the two lines of the feeder line break their symmetry, and an unnecessary radiated signal from a television receiver gets on one of the lines. It is easy to be caught by devices placed close to a television receiver, such as a television receiver.

In FIG. 1, 1 indicates an unbalanced signal suppression transformer connected to feeder lines 3a and 3b coupled to the rod antenna 2, and 4 indicates an unbalanced signal suppression transformer connected between the unbalanced signal suppression transformer 1 and the tuner 5. It shows an impedance conversion transformer that converts 300Ω impedance to 75Ω impedance.

In this way, the unbalanced signal suppression transformer 1 to which the present invention is directed is used in a television receiver by being connected to the impedance conversion transformer 4 , so in the following explanation, this impedance conversion transformer will also be explained. I'll decide.

By the way, these conventional transformers 1' and 4' were constructed from a complicated balanced transformer 6 and an unbalanced transformer 7, respectively, as shown in FIG.

That is, the unbalanced signal suppression transformer 6 has the first and second
The coils 8 and 9 are wound around one half of the glasses-shaped core, and the third and fourth coils 10 and 11 are wound around the other half of the glasses-shaped core to form a single component, and impedance conversion is also performed. The transformer 4 also had first and second coils 12 and 13 wound around one half of a separate glasses-shaped core, and third and fourth coils 14 and 15 wound around the other half. However, a transformer with such a complicated structure would result in high costs and poor productivity, so it would be desirable to have a simple structure.

The present invention was developed based on this viewpoint, and its purpose is to realize an unbalanced signal suppression transformer with an extremely simple configuration. In this case, consideration should also be given to the structure to ensure that the characteristics are not deteriorated.

Another object of the present invention is to simplify the unbalanced signal suppression transformer so that it can be integrated with an impedance conversion transformer.

As can be seen from FIG. 3 showing the circuit configuration of a transformer embodying the present invention, the transformer coils of the unbalanced signal suppression transformer 1 of the present invention have first and second coils 16 of the same polarity and tightly coupled. , 17. Output ends c and d of this coil are connected to both ends a and b of a coil 18 of an impedance conversion transformer 4 configured as an autotransformer whose center point is grounded, while input ends g and h are connected to the line 3 of the feeder wire.
a, 3b. In the unbalanced signal suppression transformer of the present invention, the unbalanced signal transmitted to the feeder line 3b is transmitted to the second coil 1.
7 to coil 1 of impedance conversion transformer 4
8 to the ground, but at this time, the unbalanced signal is greatly attenuated by the second coil 17, so the unbalanced signal induced at the output terminal a is so small that it can be ignored. Similarly, feeder line track 3a
Even if an unbalanced signal appears on the side, the first coil 16
As a result, unbalanced signals are significantly attenuated. In this way, the unbalanced signal is transmitted to the first and second coils 1.
6 and 17, the unbalanced signal is suppressed by the unbalanced signal suppression transformer 1 , which is simply configured with
7 is tightly coupled and has the same polarity, so this transformer
1 is considered to have zero impedance with respect to the received signal source, and no attenuation is performed.

Although FIG. 3 only shows the circuit configuration, the unbalanced signal suppression transformer of the present invention has the first and second coils 16, 1 in the core as shown in FIGS. 4 to 6.
7 is completed by winding the core, and the shape of this core is also one of the features of the present invention.

In addition, when the first and second coils 16 and 17 are bifilar-wound, the distributed capacitance between both coils 16 and 17 will be affected, and characteristics such as unbalanced signal suppression ratio, signal loss, and standing wave ratio will deteriorate to some extent. Therefore, in the present invention, the first and second coils are arranged adjacent to each other without being bifilar-wound.
However, in this case, as shown in FIG. 7 (the coil lead wire is omitted), the winding hole 20 of the core 19
If the portion 21 through which the coil wire is wound is curved in a circular shape, the first coil 16 and the second coil 17 tend to separate from each other, making it impossible to obtain a sufficient coupling between the two coils 16 and 17. , there is a risk of disturbing the balanced signal (that is, the original received signal), so the shape of the core (ferrite core) used in the present invention is unbalanced as shown in each embodiment of FIGS. 4 to 6. The first of the signal suppression transformer 1 ,
The protrusion 2 is formed so that the portion 22b where the second coils 16 and 17 are wound through the winding hole 22a is linear and has a gentle slope at both ends.
2c and 22c are provided. Such core 22,2
According to 2' and 22'', even if the first coil 16 and the second coil 17 are wound adjacent to each other, each coil wire does not shift toward the end from its winding position and is wound around the end due to the inclination. The coiled portion is biased towards the center and a sufficient bond can be obtained.
Although only the unbalanced signal suppression transformer part is shown in FIG. 4, in FIGS. . The coil 18 of the impedance conversion transformer is wound around a circularly curved portion. However, since the coil of the impedance conversion transformer 18 may be wound in a bi-filter as shown in the figure (experimentally confirmed), the winding position of the coil wire will hardly be distorted even if it is wound around the curved part 22d. Therefore, it is also possible to use a spectacle-shaped core 22 with different left and right shapes as shown in FIG.

As explained above, the unbalanced signal suppression transformer of the present invention has a protrusion formed with a gentle slope at the end of the core portion around which the coil is wound through the winding hole. The coil portions wound at the ends are biased toward the center, and two adjacently wound coils can be coupled sufficiently tightly. Furthermore, since the unbalanced signal suppression transformer of the present invention has a much simpler structure than conventional ones, it is extremely advantageous in terms of cost reduction and high productivity. Moreover, the structure has been devised so as not to impair its original characteristics.

In particular, in order to avoid attenuating the original balanced signal, it is necessary to have the same polarity and close coupling.
In order to obtain this tight coupling, if the first and second coils are wound with a bifilar winding, the effect of distributed capacitance will occur, resulting in loss of balanced signals and deterioration of the standing wave ratio characteristics. By arranging the cores adjacent to each other, such inconvenience can be eliminated, and by configuring the core shape as described above, sufficient tight coupling can be obtained.

Furthermore, the simplification allows integration with a similarly simplified impedance conversion transformer, which is convenient.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram showing an unbalanced signal suppression transformer together with its related circuits. FIG. 2 is a wiring diagram showing a conventional unbalanced signal suppression transformer together with an impedance conversion transformer. FIG. 3 is a wiring diagram showing the unbalanced signal suppression transformer of the present invention together with an impedance conversion transformer. FIG. 4 is a perspective view showing the structure of an unbalanced signal suppression transformer embodying the present invention, and FIGS. 5 and 6 are perspective views of other embodiments. FIG. 7 is a drawing for explaining the present invention. 1 ...Unbalanced signal suppression transformer, 2, 2...Antenna, 3a, 3b...Feeder line, 4 ...
...Impedance conversion transformer, 16...First coil, 17...Second coil, 22, 22', 2
2″...Core, 22a...Winding hole, 22b...Winding portion of core, 22c, 22c...Protrusion.

Claims (1)

[Scope of utility model registration request] An unbalanced impedance conversion transformer consisting of a first and second coil individually connected to both ends of an impedance conversion transformer coil consisting of a single-turn transformer with one end connected to the feeder line and the other end grounded at the center, which is mounted on the feeder line. An unbalanced signal suppression transformer that suppresses a signal, wherein the impedance conversion transformer coil is wound around one leg, and a protrusion is provided at the end of the other leg of the glasses-shaped core, and the coil is wound around the end of the glasses-shaped core. The protrusion at the end is formed to have a gentle slope so that the coil portion is biased toward the center, and the first and second coils are adjacent to each other so as to have the same polarity as the other leg. An unbalanced signal suppression transformer characterized in that it is wound and arranged.