JP5380010B2 - Branch adapter - Google Patents

Description

  The present invention relates to a branch adapter that branches a large number of high-frequency signals flowing through a transmission line, and that can match impedance and minimize loss in both directions of the transmission line.

  As branch adapters (distributors) for branching (distributing) a high-frequency signal flowing through a transmission line, various branch adapters have been proposed as means for branching high-frequency signals such as CATV. As such a branch adapter, a two-branch adapter having a two-branch output using a single transformer or a multi-branch adapter having a multi-branch output by an electric circuit combining a plurality of transformers has been proposed. .

  As a two-branch adapter having a two-branch output terminal, for example, the invention described in Patent Document 1 below has been proposed. In Patent Document 1, as a distributor for branching a high-frequency signal such as CATV, an impedance matching transformer T1 and a signal distribution transformer T2 in which a single ferrite core is wound are arranged on a substrate. A high-frequency signal distributor is described in which the matching transformer T1 and the distribution transformer T2 are coupled by a metal plate. Further, Patent Document 1 describes that the matching transformer T1 is grounded via the correction resistor Rs and the capacitor Cs so that the output impedance of the matching transformer T1 is constant with respect to the frequency. Yes.

  As a branch adapter provided with a multi-branch output terminal, for example, the invention described in Patent Document 2 below has been proposed. In Patent Document 2, as a 6 divider that divides a high-frequency signal used in a CATV system or the like into six equal parts, a first distribution transformer T10 (two distribution transformers), a first matching transformer T20, and the like from the input terminal side, A 6-distributor is described in which a second distribution transformer T30 (three distribution transformers) and a second matching transformer T40 are arranged in this order. Furthermore, Patent Document 2 describes that by disposing each transformer as described above, it is possible to suppress deterioration in a high frequency signal in a high region and obtain a stable impedance.

JP 2002-271161 A Japanese Patent No. 3153559

  The high-frequency signal distributor described in Patent Document 1 is a distributor that divides a high-frequency signal into two by disposing an impedance matching transformer T1 and a signal distribution transformer T2, and further divides the high-frequency signal into three or more branches. The configuration for branching into multiple branches is not disclosed. The high-frequency signal distributor described in Patent Document 1 is provided with means for impedance matching when a high-frequency signal flows in one direction from the input terminal side to the output terminal side. It is not a distributor for flowing a signal from the output terminal side to the input terminal side, that is, a distributor used for flowing a high-frequency signal bidirectionally through the transmission line.

  The 6 distributor described in Patent Document 2 includes a first distribution transformer T10 (two distribution transformers), a first matching transformer T20, a second distribution transformer T30 (three distribution transformers) from the input terminal side, By arranging the second matching transformer T40 in this order, the distributor is divided into six parts. However, similar to the above-mentioned Patent Document 1, it is used for flowing a high-frequency signal bidirectionally on the transmission line. It is not a distributor.

  In a network system including a communication line for performing data communication, a high-frequency signal serving as a data signal flows bidirectionally on the communication line (transmission path). When a large number of terminal devices are connected to the network system, it may be necessary to branch the transmission path into a large number. For example, it is a network system using PLC (Power Line Communication) communication that performs communication using an AC 100V power line.

  For example, in a large-scale building or the like, when connecting a terminal device such as a personal computer or various electric (electronic) devices arranged on each floor via a network using PLC communication, it is wired to the floor. It is necessary to branch the power line into a larger number and connect it to these electronic devices. Patent Documents 1 and 2 described above are not branch adapters for the purpose of flowing a high-frequency signal bidirectionally in the transmission path of the network system described above.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a branch adapter that can branch a high-frequency signal into a large number, can achieve impedance matching even when a high-frequency signal is passed in both directions, and can minimize branch loss. There is. In particular, the present invention is to provide a branch adapter for branching a transmission line of a network system using PLC communication into a large number.

In order to solve the above-described problem, the branch adapter according to the invention described in claim 1 is configured such that one impedance element is connected to one diagonal of a bridge constituted by four impedance elements, and the other diagonal. A bridge circuit in which one impedance element is connected to each other, wherein the four impedance elements constituting the bridge are constituted by four transformer elements , and the bridge is formed by connecting the secondary side of each transformer. And one impedance element connected to the one diagonal is configured by a transformer element, and the secondary side of the transformer element is connected to one diagonal of the bridge, and the other diagonal is One impedance element to be connected is constituted by a resistor, and the primary side of the transformer element connected to the one diagonal is used as transmission data. In addition to an input terminal to which a high-frequency signal is input, the primary side of each of the four transformer elements constituting the bridge is an output terminal to which an external device is connected .

The branch adapter according to the second aspect of the present invention relates to two sets of two transformer elements in which one of the secondary sides of the transformer elements is connected to each other. A circuit having a combination of four transformer elements in which the secondary sides are connected to each other and the connected secondary sides are connected through a resistor, and an input terminal to which a high-frequency signal serving as transmission data is input on the primary side A pre-branch port transformer element, wherein one of the secondary sides of the pre-branch port transformer element is connected to one connecting portion connecting the secondary sides of the two transformer elements, and the branch consists arrangement connected the other of the secondary side before transformer device port to the other connection portion connecting the hand each other on the secondary side of the two transformer device, the primary of the four transformer element Were a branch after the port is an output terminal of an external device is connected, it is characterized in that.

According to the third aspect of the present invention, there is provided a branch adapter according to the present invention, wherein two sets of two transformer elements connected to each other on the secondary side of a transformer element are connected to the other two transformer elements. Bridges 1, 2, 3, 4, which have a bridge configuration including a combination of four transformer elements in which the secondary sides are connected to each other and the connected secondary sides are connected via resistors. And a pre-branching port transformer element having the primary side as an input terminal to which a high-frequency signal serving as transmission data is input, and the secondary side connected via the resistors of the bridge 1 and the bridge 2 with connecting no one secondary-side each other, and connected to one of the secondary side of the transformer device for the branch before port, via the resistor of the bridge 3 and the bridge 4 With connecting one of the secondary-side each other not continue to secondary side, connected to the other of the secondary side the branch before transformer device port, connected through the resistor of the bridge 1 and the bridge 3 Connected to the other secondary side that is not the secondary side (hereinafter referred to as between the bridges 1-3), and the other non-secondary side that is connected via the resistance of the bridge 2 and the bridge 4 The secondary sides are connected to each other (hereinafter referred to as between the bridges 2-4), the bridges 1-3 are connected to the bridges 2-4 via resistors, and the bridge 1 and the bridge 2 The primary side of the 16 transformer elements that constitute the bridge 3 and the bridge 4 is a post-branching port that is an output terminal to which an external device is connected.

  According to a fourth aspect of the present invention, there is provided the branch adapter according to any one of the first to third aspects, wherein the transformer element has a winding ratio of 1: 1 between the primary side and the secondary side. It is characterized by being.

  A fifth aspect of the present invention relates to the branch adapter according to any of the first to fourth aspects, wherein the primary side of the transformer element is connected between the connection port and the primary side. It is characterized by having a coupling capacitor.

  The invention according to claim 6 relates to the branch adapter according to any one of claims 1 to 5, wherein the primary side of the transformer element operates a terminating resistor provided between the connection ports. The switch means is provided.

  According to the present invention, it is provided with a configuration in which five transformer elements having a primary / secondary coil turns ratio of 1: 1 are connected so as to form a bridge-structured circuit. Since the impedance element is provided, it is possible to minimize the bidirectional branch loss of the high-frequency signal in the transmission line, and further provide a four-branch branch adapter capable of matching the bidirectional impedance of the transmission line. can do.

The present invention further provides a 16-branch branch adapter by forming four sets of five transformer elements connected so as to form a bridge-structured circuit into a multiple structure so as to form a bridge-structured circuit. can do.
Further, the branch adapter of the present invention can be used as a branch adapter having 2 to 15 branches by connecting a termination resistor to the post-branch port. Thereby, especially this invention can exhibit an effect as a branch adapter for branching the transmission path of the network system using PLC communication which connected many terminal devices to many.

  As described above, conventionally, a high-frequency transformer element that branches in two directions or the like is used as a means for branching a transmission line. In order to connect a large number of electronic devices such as terminal devices on a network, for example, Therefore, it is necessary to use a branch adapter in which the transmission path is branched into a large number of four branches or more and impedance matching is performed in both directions. That is, such a branch adapter needs to satisfy the requirements described in 1) to 3) below.

  1) Since the transmission path is branched into a large number, the bidirectional branch loss increases, but this is minimized. Furthermore, bidirectional impedance matching is taken.

  2) AC100V as a power line can be coupled, and when realizing a branch adapter composed of a high-frequency transformer element, insulation between the primary and the ground and between the primary and secondary is ensured. Further, the termination resistor is automatically or manually opened or disconnected when an electronic device is connected to all the branched ports of the branch adapter and when an electronic device is not connected to a part of the branched port. The configuration is such that connection is possible, and the above-described bidirectional (downward and upstream) impedance matching is achieved.

  3) Since a transmission line of a network connecting a large number of electronic devices is branched by a branch adapter, a single transmission line is configured to be capable of performing multi-branching so that a maximum of 16 branches can be performed.

  In order to solve the above requirements, the branch adapter of the present invention is realized based on the technical idea described in the following 1) to 5).

  1) In a circuit in which the six impedance elements Z0 to Z5 shown in FIG. 1 are coupled to form a bridge circuit, the impedance elements Z0 to Z5 are unified to 50Ω. In the circuit in which the impedance elements Z0 to Z5 form a bridge configuration, the impedance viewed from the impedance element Z5 is 50Ω, and the impedance viewed from the impedance element Z0 is also 50Ω. Similarly, the impedance viewed from the impedance elements Z1, Z2, and Z3 is 50Ω. Also, the impedance viewed from the opposite side is 50Ω respectively.

  2) Further, in the bridge circuit shown in FIG. 1, when the impedance element Z5 is a driving impedance and the impedance element Z0 is a termination impedance, the voltage level between the impedance elements Z5 and Z0 is reduced by 6 dB. The branch loss between Z5 and the impedance elements Z1, Z2, and Z3 is also reduced by 6 dB.

  3) Conversely, when the impedance element Z0 is the drive impedance and the impedance element Z5 is the termination impedance, the voltage level between the impedance elements Z0 and Z5 is 6 dB down, and similarly, the impedance elements Z1, Z2, and Z3 are respectively set to Even when driving impedance is used, the voltage level can be reduced by 6 dB.

  4) That is, in the bridge circuit shown in FIG. 1, all impedance elements constituting the bridge are unified to 50Ω and branched to the first intermediate points a and c (diagonals a and c shown in FIG. 1) of the bridge circuit. If one of the previous impedance elements Z5 is connected and the impedance element Z4 arranged between the diagonal (b, d), that is, between the second intermediate points b and d, is terminated as a 50Ω resistor, a bidirectional branch loss Can be realized and a bi-directional impedance matching can be realized. That is, among the six impedance elements constituting the bridge circuit, the impedance element (Z4) connecting one diagonal formed by the bridge circuit is set as a termination resistor having a predetermined resistance value.

  5) Instead of the impedance elements Z0, Z1, Z2, Z3 and Z5 shown in FIG. 1, transformer elements are used, and the primary side of these five transformer elements is used as a port (terminal) for connecting to an external device. . Furthermore, the secondary side of these transformer elements is used as a component constituting the bridge circuit, and by constructing a bridge in which the impedance element Z4 is terminated as a 50Ω resistor, between the primary and primary, between the primary and secondary A branch adapter that can ensure insulation can be realized.

  Below, the embodiment is described about the branch adapter of the present invention developed based on the above-mentioned technical idea. FIG. 2 is a circuit configuration diagram showing the first embodiment of the branch adapter of the present invention, and shows an example of a four-branch branch adapter.

(First embodiment)
FIG. 2 shows a circuit configuration example of the branch adapter 1 having a four-branch configuration. The branch adapter 1 is configured to form a bridge-structured circuit of five small high-frequency transformer elements (hereinafter referred to as “transformer elements”) composed of ferrite cores. The ratio of the number of windings of the primary and secondary coils of each transformer element is set to 1: 1. Moreover, since it is a high frequency transformer element, the number of turns may be about 2 to 4 turns. Furthermore, the transformer element can be manufactured in a small and thin shape of about 1 cm ³ . Furthermore, a single branch adapter can be unitized by arranging a plurality of transformer elements on a substrate to form a circuit.

  The branch adapter 1 shown in FIG. 2 connects five transformer elements (2-1) to (2-5) so as to form a circuit having a bridge structure, and has four branch output terminals (post-branch ports). ) It is set as the structure provided with P1-P4. As shown in FIG. 2, among the five transformer elements, the primary side of the transformer element (2-1) is a network communication line, or in the case of a network using PLC communication, an input side terminal for connecting a power line ( Hereinafter, the transformer element is referred to as a “port before branch”. The primary side of each of the four transformer elements (2-2) to (2-5) is used as an output terminal (hereinafter referred to as “post-branch port”) to which an electronic device as an external device is connected. As a result, the branch adapter 1 includes the post-branch ports P1, P2, P3, and P4 in which the pre-branch port P0 is branched into four by a circuit that forms a bridge.

The circuit configuration of the four-branch branch adapter 1 shown in FIG. 2 will be described in detail as follows.
The primary side of the transformer element (2-1) serving as the pre-branch port, that is, the pre-branch port P0 is a terminal connected to a power line that supplies AC 100V. In the example shown in FIG. 2, this pre-branch port P <b> 0 indicates that a power line (AC 100 V) branched from the distribution board B is connected.

  Then, one of the secondary sides of the transformer element (2-1) is connected to a conducting wire connecting the two transformer elements (2-2) and one of the secondary sides of the transformer element (2-4) as a connection point 3a. Connecting. Further, the other secondary side of the transformer element (2-1) is connected as a connection point 3b to a conductor connecting the two transformer elements (2-3) and the other secondary side of the transformer element (2-5). .

  Furthermore, the other secondary side of the transformer element (2-2) and the transformer element (2-4) is connected to the other secondary side of the transformer element (2-3) and the transformer element (2-5), respectively. While connecting as points 4a and 4b, connecting points 4a and 4b are connected through a resistor 6 of 50Ω. Further, a coupling capacitor 5 is connected to the primary side of the transformer element (2-1) connected to the power line, and the primary side of the transformer elements (2-2) to (2-5) is also connected to the capacitor 5 after branching. Port. Thereby, the secondary side of each transformer element becomes a component constituting the bridge circuit.

  In the branch adapter 1 having the configuration shown in FIG. 2, even if the primary side of the transformer element (2-1) is connected to the power line supplying AC 100V with the pre-branch port P0, the AC 100V is cut by the coupling capacitor 5 and the transmission data Only the high-frequency signal that flows through the circuit constituting the branch adapter 1 flows. Thereby, the branch adapter 1 can be made into the branch adapter which can be connected to AC100V.

  Further, since the five transformer elements (2-1) to (2-5) are connected so as to form a bridge configuration, the primary side of each transformer element constituting the branch adapter 1 is in the upstream and downstream directions. When viewed from the direction, the impedance is the same, that is, impedance matching can be achieved both in the downstream and upstream directions of the transmission path. Further, the bridge configuration can minimize the loss at the branch even if the transmission path is branched into four. Further, since the coupling capacitor 5 is connected to the primary side of each transformer element (2-1) to (2-5) and the external device 7 is connected to the primary side, the transformer element is connected between the primary and secondary sides. Insulation and the withstand voltage of the branch adapter 1 can be secured.

  FIG. 3 shows the branching adapter 1 shown in FIG. 2, the post-branching ports P1 to P4 on the primary side of the transformer elements (2-2) to (2-5), for example, the transformer element (2-5) (port In the case where it is not necessary to connect the electronic device 7 to P4), an example is shown in which the impedance matching described above is performed by connecting a 50Ω termination resistor 8 to the primary side of the transformer element (2-5). . In this way, by connecting the 50Ω termination resistor 8 to any of the post-branch ports P1 to P4 not connected to the electronic device 7, the four-branch branch adapter 1 shown in FIG. Can be used as a branch adapter. Further, when a 50Ω termination resistor is actually connected, a configuration as shown in FIG.

(Second Embodiment)
Next, a second embodiment of the branch adapter according to the present invention will be described with reference to FIG. FIG. 4 shows a circuit configuration example of the branch adapter 11 having 16 branches. This 16-branch branch adapter 11 has a circuit having a bridge structure shown in FIG. 2 as a unit, and four of these units are further arranged to form a bridge structure. It is a thing.

  The branch adapter 11 of 16 branches shown in FIG. 4 includes four high-frequency transformer elements (2-2) to (2-5) having the bridge configuration shown in FIG. 1 as one bridge configuration pattern (pattern A1, FIG. A2, A3, and A4), and four of these bridge configuration patterns are further arranged to form a bridge configuration so that 16 post-branching ports P1 to P16 are formed. is there. That is, as shown in FIG. 4, one high-frequency transformer element (2-1) is a pre-branch transformer and its primary side is a pre-branch port P0, and 16 high-frequency transformer elements (2-2) to (2) −17) The primary side is the post-branch ports P1 to P16, and the circuit configuration includes a total of 16 post-branch ports.

The details of the circuit configuration of the 16-branch branch adapter 11 shown in FIG. 4 will be described as follows.
1) One side of the secondary side of the transformer elements (2-2) and (2-4) constituting the bridge configuration pattern A1 is connected by a conducting wire. Similarly, one of the secondary elements of the transformer elements (2-10) and (2-12) constituting the bridge configuration pattern A2 is connected to each other, and connection points (3a-1) and (3a) of these connected conductors are connected. -2) is connected by the conducting wire 9a.

  2) Similarly to the above 1), the connection points 3b-3 and 3b-4 are provided for the bridge configuration patterns A3 and A4, and these connection points (3b-3) and (3b-4) are connected by the conductor 9b. To do.

  3) One of the secondary sides of the transformer elements (2-3) and (2-5) constituting the bridge configuration pattern A1 is connected by a conducting wire. Similarly, one of the secondary elements of the transformer elements (2-6) and (2-8) constituting the bridge configuration pattern A3 is connected to each other, and connection points (3b-2) and (3a) of these connected conductors are connected. -3) is connected by the conducting wire 9c.

  4) The transformer elements (2-11) and (2-13) constituting the bridge configuration pattern A2 are connected to each other on the secondary side with a conductive wire. Similarly, one of the secondary elements of the transformer elements (2-14) and (2-16) constituting the bridge configuration pattern A4 is connected to each other, and connection points (3b-2) and (3a) of these connected conductors are connected. -4) is connected by the conductor 9d.

5) The conductors 9c and 9d are connected via a 50Ω resistor 6.
6) One of the secondary sides of the transformer element (2-1) arranged as the input terminal (pre-branch port) P0 of the branch adapter 11 is connected to the lead wire 9a, and the other secondary side is connected to the lead wire 9b.
7) A capacitor 5 is connected to the primary side of each of the high-frequency transformer elements (2-2) to (2-17) constituting the four bridge configuration patterns A1, A2, A3, and A4.

  The other circuit configuration is the same as that of the 4-branch branch adapter 1 shown in FIG. For example, in the bridge configuration pattern A1, one of the secondary sides of the transformer elements (2-2) and (2-3) is connected to each other, and similarly the secondary of the transformer elements (2-4) and (2-5) Connect one side of the other. These connection points 4a and 4b are connected through a resistor 6 having a resistance of 50Ω.

  In the 16-branch adapter 11 having the circuit configuration described above, the 16 primary sides of the transformer elements (2-2) to (2-17) constituting the four bridge configuration patterns A1, A2, A3, and A4 are branched. The external device 7 is connected as a rear port. In addition, a power line or a communication line is connected to the primary side of the transformer element (2-1) serving as the pre-branch port of the branch adapter 11.

  Also in the 16-branch adapter 11 shown in FIG. 4, when the external device 7 is not connected to the post-branch port, as shown in FIG. 3, a 50Ω termination is provided on the primary side of the transformer element of the unused post-branch port. A resistor 8 is connected so that impedance matching is achieved. As a result, the branch adapter 11 shown in FIG. 4 can be used as a branch adapter having a maximum of 16 post-branch ports.

  FIG. 5 shows a configuration example of the transformer element 20 in which each transformer element shown in FIGS. 2 and 4 is provided with switch means for automatically or manually operating the terminating resistor. The transformer element 20 shown in FIG. 5 shows a configuration in which a switch Sw and a 50Ω termination resistor 8 are connected in series between terminals on the primary side. When the primary side of the transformer element 20 is used as a post-branch port, the switch Sw is “opened (opened: OFF)” by manual operation so that the terminating resistor 8 does not operate. On the other hand, when the primary side of the transformer element 20 is not used as a post-branching port, the switch Sw is “closed (ON)” by manual operation so that the terminating resistor 8 is activated. The switch Sw is opened / closed by using a photo relay or the like so that the switch Sw is automatically “opened” when the electronic device is connected, and the switch Sw is automatically “opened” when the electronic device is not connected. It is possible to perform the control of “closed (ON)”.

  The first embodiment according to the above-described branch adapter of the present invention includes a post-branch port of 4 branches and the second embodiment of 16 branches. Since the above-mentioned switch means is provided in the post-branch port, the post-branch port should be used as an effective port according to the number of terminal devices such as electronic devices connected to the network. Can do. The branch adapter according to the present invention is manufactured by forming a wiring pattern in which five or seventeen high-frequency transformers form a bridge circuit as shown in FIG. 2 or FIG. Then, the impedance (resistance), the modular jack, the switch means, etc., and the AC100V terminal, etc., which are the pre-branch port and post-branch port are fixed. Then, the substrate is housed and fixed in a synthetic resin casing.

  The branch adapter according to the present invention has a configuration in which high-frequency transformer elements are connected so as to form a bridge-structured circuit, and the bridge-structured circuit has a multiple structure, and a coupling capacitor is provided on the primary side. In addition, the bridge-structured circuit is equipped with a 50Ω impedance element, so that it is possible to minimize the branch loss of the high-frequency signal in the transmission line, and to achieve bidirectional impedance matching of the transmission line. A branch adapter that can be provided can be provided. As a result, the present invention is particularly effective when used as an adapter for branching the transmission path into a large number in a PLC communication network system that performs communication using a power line.

It is a figure for demonstrating the basic composition of the circuit about the branch adapter of this invention. It is a figure for demonstrating the circuit structural example of a 4-branch branch adapter about the branch adapter of this invention. It is a figure which shows the state which connected the termination resistance to one of the ports after a branch of the branch adapter shown in FIG. It is a figure for demonstrating the circuit structural example of the branch adapter of 16 branches about the branch adapter of this invention. FIG. 5 is a diagram showing a circuit example in which switch means is provided on the primary side of the transformer element shown in FIG. 2 or FIG.

Explanation of symbols

1: Branch adapter (branch adapter with 4 branches)
2-17: High frequency transformer element 5: Coupling capacitor 6: Resistance 7: Electronic device (external device)
8: Termination resistor 11: Branch adapter (branch adapter with 16 branches)
A1, A2. A3. A4: Bridge configuration pattern P0: Port before branch (input terminal: connection port)
P1, P2, P3,..., P16: Port after branching (output terminal: connection port)
Sw: Switch means

Claims (6)

A bridge circuit in which one impedance element is connected to one diagonal of a bridge constituted by four impedance elements, and one impedance element is connected to the other diagonal ;
The four impedance elements constituting the bridge are constituted by four transformer elements, and the bridge is constituted by connecting the secondary side of each transformer,
One impedance element connected to the one diagonal is constituted by a transformer element, and the secondary side of the transformer element is connected to one diagonal of the bridge,
One impedance element connected to the other diagonal is constituted by a resistor,
The primary side of the transformer element connected to the one diagonal is used as an input terminal for inputting a high-frequency signal as transmission data, and an external device is connected to the primary side of each of the four transformer elements constituting the bridge. Output terminal,
Branch adapter characterized by that. For two sets of two transformer elements connected to one of the secondary sides of the transformer elements, the other secondary sides of the transformer elements of each set are connected to each other, and the connected secondary sides are connected to each other. A circuit having a combination of four transformer elements connected via a resistor;
A pre-branch port transformer element having the primary side as an input terminal to which a high-frequency signal serving as transmission data is input,
One of the secondary sides of the transformer element for the pre-branch port is connected to one connecting portion connecting one of the secondary sides of the two transformer elements, and the other of the secondary side of the transformer element for the branch port the result from the configuration connected to the other connection portion connecting the hand each other on the secondary side of the two transformers element,
The primary side of the four transformer elements is a post-branching port that is an output terminal to which an external device is connected.
Branch adapter characterized by that. For two sets of two transformer elements connected to one of the secondary sides of the transformer elements, the other secondary sides of the transformer elements of each set are connected to each other, and the connected secondary sides are connected to each other. , A bridge configuration having a combination of four transformer elements connected via a resistor, a bridge 2, a bridge 3, a bridge 4, and
A pre-branch port transformer element having a primary side as an input terminal to which a high-frequency signal serving as transmission data is input,
Connecting one secondary side that is not the secondary side connected via the resistor of the bridge 1 and the bridge 2 to each other and one secondary side of the transformer element for the port before branching;
Connecting one secondary side which is not the secondary side connected via the resistor of the bridge 3 and the bridge 4 to each other, and connecting to the other secondary side of the transformer element for the pre-branch port,
The bridge 1 and the said connection and the other secondary-side each other not via a resistor connected secondary side of the bridge 3 (hereinafter, referred to as between the bridge 1-3) and the of the bridge 2 and the bridge 4 The other secondary side that is not the secondary side connected through a resistor is connected to each other (hereinafter referred to as between the bridges 2-4), and the resistance between the bridge 1-3 and the bridge 2-4 is reduced. Connect through
The primary side of the 16 transformer elements constituting the bridge 1, the bridge 2, the bridge 3, and the bridge 4 is a post-branch port that is an output terminal to which an external device is connected.
Branch adapter characterized by that.   4. The branch adapter according to claim 1, wherein the transformer element has a winding ratio of a primary side and a secondary side of 1: 1. 5.   The branch adapter according to any one of claims 1 to 4, wherein a primary side of the transformer element includes a coupling capacitor connected between a connection port of the transformer element and the primary side.   The branch adapter according to any one of claims 1 to 5, wherein the primary side of the transformer element includes switch means for operating a terminating resistor provided between the connection ports.

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