JPS59198017A - Device for distributing signal into three - Google Patents

Abstract

PURPOSE:To reduce the distribution loss and also the variation in the distribution loss to each distribution output terminal by connecting the 1st and 2nd directional coupling transformer to each output terminal of a 2-distribution transformer. CONSTITUTION:A 2-distribution transformer 16 distributes an input signal from input terminals 15, 15' into two. The 1st directional coupling transformer 17 is connected to the 1st output terminal (d) of the transformer 16 and the 2nd directional coupling transformer 18 is connected to the 2nd output terminal (e). Branch terminals b, b' of the transformers 17, 18 are connected in common. An output terminal c' of the tranformer 17 is taken as the 1st distribution output terminals 19, 19', an output terminal c'' of the transformer 18 is taken as the 2nd distribution output terminals 20, 20' and a common connecting point of the terminals b, b' is taken as the 3rd distribution output terminals 21, 21'. The variation in the distribution loss is decreased and also the entire distribution loss is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a signal splitting device that can be used in the VHF-UHF frequency band for television communal viewing equipment, CATV equipment, and the like.

Conventional configuration and its problems FIG. 1 shows a circuit diagram of a conventional signal splitter.

In Figure 1, 1.1' is a 75Ω unbalanced input terminal,
2 is a matching/distribution transformer which integrates a matching transformer 2a and a distribution transformer 2b.

3 and 4 are distribution transformers respectively, 5.5' is 75Ω
6.6' is the unbalanced first distribution output terminal, 6.6' is the 75Ω unbalanced second distribution output terminal, and 7,7' is the 75Ω unbalanced third distribution output terminal.
8 is a terminal resistor with rated impedance (75Ω), R to R3 are resistors, and C to C3 are capacitors.

This two-signal distribution device divides an input signal into two by a matching/distribution transformer 2, divides each of the two divided signals into two by distribution transformers 3 and 4, and distributes the signal into four in total. One of the four distributed outputs is connected to the terminal resistor 8.
In addition to both ends of , the remaining three outputs are used.

This circuit configuration 1 consists of an input terminal 1.1' and a distribution output terminal 5.
．． 5'; 6, 6'; and 7, 7', the variation in distribution loss can be made relatively small. However, since one output of the single-distribution transformer 4 is consumed by the terminating resistor 8, there is a drawback that the distribution loss is large.

FIG. 2 shows a circuit diagram of another conventional signal pressure distribution device. In FIG. 2, 9.9' is a 75Ω unbalanced input terminal, 10 is a directional coupling transformer, and 11 is a matching/distribution transformer which integrates matching transformer IIB and distribution transformer Ilb. 12 and 12' are 75Ω unbalanced first distribution output terminals, 13 and 13' are 75Ω unbalanced second distribution output terminals, and 14 and 14' are 75Ω unbalanced third distribution output terminals. R4°R5 is a resistor s, and C4 is a capacitor.

This signal pressure distribution device applies an input signal to a directional coupling transformer 10, divides the signal from the output terminal of the directional coupling transformer 1 into two by a matching/distribution transformer 11, and outputs a first and second distribution output. At the same time, the signal from the branch terminal of the directional coupling transformer 1o is used as the third distribution output.

This circuit configuration has relatively small distribution loss, but each distribution output terminal 12, 12', 13, 1.3', 14.1
There was a drawback that the distribution loss to 4' varied widely.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a signal pressure distribution device that can reduce distribution loss and reduce variations in distribution loss to each distribution output terminal.

Structure of the Invention The signal pressure distribution device of the present invention divides an input signal into two parts.
a distribution transformer; a first directional coupling transformer having an input terminal connected to a first output terminal of the two-way distribution transformer; a second directional coupling transformer commonly connected to a branch terminal of the first directional coupling transformer;
The output terminal of the second directional coupling transformer is a second distribution output terminal, and the common connection point of the branch terminals of the first and second directional coupling transformers is a third distribution output terminal.
The device is characterized in that it has a distribution output terminal.

By configuring in this way, it is possible to reduce the variation in each distribution loss, and also to reduce the overall distribution loss.

DESCRIPTION OF THE EMBODIMENTS A signal pressure distribution device according to an embodiment of the present invention will be described with reference to FIGS. 3 to 8. In Figure 3, 15, 1
5' is a 75Ω unbalanced input terminal, 16 is input terminal 15
, 15' is a matching/distribution transformer that divides the input signals from the input signals into two, and the matching transformer 16& and the distribution transformer 16b are integrated. 17 and 18 are matching/distribution transformers 1
A directional coupling transformer that receives the two distribution outputs of 6 as inputs, the signals from each output terminal are used as the first and second distribution outputs, and the signal from the common connection point of each branch terminal is used as the third distribution output. It is used as output. 19 and 19' are first distribution output terminals, and 20 and 20' are second distribution output terminals.

21 and 21' are third distribution output terminals.

The matching transformer 16a has an input/output impedance ratio of 2:
1, and the impedance of 75Ω between 8 and 0 is changed to 375Ω between be and e. Directional coupling transformer 17
．． Since the impedance between 87 and 01 and between 8' and C' is extremely small, the loss between them is about 2 dB at most. Therefore, if the coil between b and 6 of the distribution transformer 16a and the coil between b and e are wound around a single ferrite core so that their magnetic fluxes cancel each other out, then the distribution output terminals 19, 19' and 20. If you connect a 75Ω terminal resistor between 20' and look at the right side from between b and ground, the impedance is half of each terminal resistor (375Ω).
The value becomes close to , and left and right impedance matching at this point is achieved. Approximately equal signal outputs are obtained at output ends d and e of the distribution transformer 16b.

The resistor R6 connected between these has the function of reducing variations in the Okayama power signal and lowering the impedance between them. Further, the capacitor C5 improves high frequency characteristics. Directional coupling transformer 17.18
The losses between 81 and 07 and between 81 and 07 are small (about 2 dB), and the losses between g and b' and between 8' and b' are slightly thick (about 5 dB).

Between b' and C', and between b' and c'f&'l, the coupling is extremely loose. The signal of the distribution output terminal 21.21' is sent to the branch terminal b' of the directional coupling transformer 17.18,
As a result of the superposition of the signal from b', the distribution output terminal 19
It becomes possible to match the signal levels of 19'; 20 and 20'. Resistors R7 and R8 are used to set the impedance of branch terminals b' and b' to the rated 75Ω, and d'
, ground and d', ground.

4 through 6 show the structure of the matching/distribution transformer 16. FIG. Figure 4 (A) is a plan view, Figure CB) is a bottom view, Figure 5 (8) is a sectional view taken along the Y-v line in Figure 4 (A), and Figure CB) is a schematic diagram of the coil portion. , FIG. 6(8) is a sectional view taken along line W-VI in FIG. 4(A), and FIG. 6(B) is a schematic diagram of the coil portion thereof. In these figures, reference numeral 31 denotes a cylindrical ferrite core, which has through holes 31a to 31d for inserting the coil in the axial direction. Matching transformer 16a
One turn is wound between &'i, a, and 5, and two turns are wound between b and c, and the b points of both coils are twisted and connected by soldering. The distribution transformer 16b is a.

One turn is wound between coils 5 and 5, and one turn is wound between coils e and 5, and points b of both coils are connected by soldering in the same manner as the matching transformer 16B. In this case, point b of the matching transformer 1 (ia) and point b of the distribution transformer 16b are twisted together and connected.

7 and 8 show the structure of the directional coupling transformer 17.18. Figure 7 (A) is a plan view, Figure 7 (B)
is a sectional view, FIG. 8(A) is a schematic diagram of the coil part, and β in the same figure
) is its circuit diagram. In these figures, 41 is a ferrite core, and 41B and 41b are through holes. 2
The primary coils 42 and 42' are wound around two turns symmetrically around the through holes 418 and 41b of the ferrite core 41. In addition, the secondary coil 43. Similarly, '43' is rolled up symmetrically by about 3 turns. After impedance matching is achieved by the matching transformer 16B, the signal from the input terminal is divided into approximately halves by the distribution transformer 16b. Directional coupling transformer 17,18 has primary coil 42
, 42' and the winding ratio of the secondary coils 43, 43',
Adjust the signal level obtained from the branch terminal (according to experiments, the signal level between the two turns of the secondary coil and the three turns of the secondary coil between terminals 21 and 21' is between terminals 19 and 19',
The signal level was approximately equal to that between 20°2O2. In this configuration, input terminals 15~/? ! The distribution loss between the r output terminals 19 to 21 was approximately 6 dB, which was an extremely small loss.

The greatest advantage of this signal pressure distribution device is that distribution loss is small. Particularly in large-scale public listening and CATV facilities, these devices are often connected continuously, so it is extremely important that the loss of each device is small, and in order to improve effectiveness in this respect. Demonstrate. Furthermore, variations in distribution loss between output terminals can be reduced.

Effects of the Invention According to the signal pressure distribution device of the present invention, variation in distribution loss can be reduced and overall distribution loss can be reduced.

[Brief explanation of drawings]

Figures 1 and 2 are circuit diagrams of a conventional signal pressure distribution device;
Fig. 3 is a circuit diagram of an embodiment of the present invention, Fig. 4 (A) is a plan view of the matching distribution transformer, Fig. 4 (B) is also a bottom view, and Fig. 5 k) is a diagram of the fourth enclosure). V-v line sectional view, Figure 5 CB) is a schematic diagram of the coil part, Figure 6 (2) is the fourth
A sectional view taken along line VI-VI in Figure (A), Figure 6 CB) is a schematic diagram of the coil portion, Figure 7 (A) is a bottom view of the directional coupling transformer, Figure 7 CB) is also a sectional view, FIG. 8) is a schematic diagram of the coil portion, and FIG. 8(B) is a circuit diagram thereof. 16...Matching distribution transformer, 17.18...Directional coupling transformer, 19-21...Distribution output terminal Fig. 1 Fig. 2 Fig. 3 (A) ' (B) Fig. 4 Fig. 5 Figure 6

Claims (1)

[Claims] a 2-distribution transformer that divides a human power signal into two; a first directional coupling transformer whose input terminal is connected to the first output terminal of the 2-distribution transformer; and an input terminal connected to the second output terminal of the 2-distribution transformer. and connect the branch terminal to the first
a second directional coupling transformer commonly connected to a branch terminal of the directional coupling transformer, wherein the output terminal of the first directional coupling transformer is a first distribution output terminal;
A signal splitting device in which the output terminal of the directional coupling transformer is a second distribution output terminal, and the common connection point of the branch terminals of the first and second directional coupling transformers is a third distribution output terminal.