JP2019186886A - Signal transmission device, signal transmission system, and method - Google Patents

Abstract

To ensure the securement of time accuracy in a transmission system that provides services by adopting a TDD radio transmission scheme.SOLUTION: A signal transmission device of an embodiment performs TDD signal transmission, and includes: a switch unit for separating a time synchronization signal from signals other than the time synchronization signal included in an input transmission signal; a first transmission path for transmitting the signals other than the time synchronization signal; a second transmission path for transmitting the time synchronization signal; and a combiner/distributer for combining a transmission signal from the first transmission path and a transmission signal from the second transmission path, and distributing a transmission signal to the first transmission path side and a transmission signal to the second transmission path side.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a signal transmission device, a signal transmission system, and a method.

  The same frequency band as the FDD (Frequency Division Duplex) method that uses two different frequency bands as a downlink signal / upstream signal as a pair, as a wireless transmission method used in mobile communication terminal devices such as mobile phones and smartphones. Is commonly used for downlink signals and uplink signals, and a TDD (Time Division Duplex) method used in time division is known.

JP 2007-006163 A Japanese Patent Laid-Open No. 11-008879 Japanese Patent Laid-Open No. 08-237731

  By the way, in the FDD wireless transmission system, a certain frequency interval (Gap) is required between the downstream frequency band and the upstream frequency band, and the available frequencies are becoming tight. In recent years, the use of a TDD wireless transmission system has increased.

Therefore, it is conceivable that the number of apparatuses using the TDD wireless transmission system will increase also in the shared repeater system.
In a shared repeater system that employs a TDD wireless transmission system, transmission and reception are performed at different timings, and the transmission speed and transmission delay amount may differ between the uplink and the downlink. It was difficult to secure.

  The present invention has been made in view of the above, and is a signal transmission that can ensure time accuracy even in a transmission system that employs a TDD wireless transmission method and provides a service. It is an object to provide an apparatus, a signal transmission system and a method.

  The signal transmission device of the embodiment is a signal transmission device that performs signal transmission by the TDD method, and separates a time synchronization signal and a signal other than the time synchronization signal included in the input transmission signal; The first transmission path for transmitting a signal other than the time synchronization signal, the second transmission path for transmitting the time synchronization signal, the transmission signal from the first transmission path, and the transmission signal from the second transmission path side are combined. And a combiner / distributor that distributes a transmission signal to the first transmission line side and a transmission signal to the second transmission line side.

FIG. 1 is a schematic configuration block diagram of a communication network according to an embodiment. FIG. 2 is a schematic configuration block diagram of the coaxial transmission device. FIG. 3 is an explanatory diagram of an example of frequency allocation to PTP packet data and other packet data. FIG. 4 is an explanatory diagram of the time synchronization processing procedure by PTP. FIG. 5 is a schematic configuration block diagram of a repeater device according to the second embodiment.

[1] First Embodiment Next, an embodiment will be described in detail with reference to the drawings.
FIG. 1 is a schematic configuration block diagram of a communication network according to an embodiment.
In the following description, it is assumed that the communication network performs communication according to the LTE (Long Term Evolution) communication standard.

  The communication network NET interconnects with another connection carrier communication network ENET via an unillustrated gateway exchange (Interconnecting Gateway Switch), and a mobile phone, a smartphone, etc. belonging to the connection carrier corresponding to the communication network NET A core network CNET that controls connection of the mobile communication terminals, a plurality of base station controllers BSC that are connected to the core network CNET and that manage and control base stations to be described later, and a coaxial cable LC to each base station controller BSC And a plurality of wireless base stations BTS connected by wire.

  In the above configuration, the base station control device BSC includes a coaxial transmission device 10A, the radio base station BTS includes a coaxial transmission device 10B, and the coaxial transmission device 10A and the coaxial transmission device 10B are arranged to face each other via a coaxial cable. .

Next, the coaxial transmission device will be described.
Since the coaxial transmission device 10A and the coaxial transmission device 10B have the same configuration, the coaxial transmission device 10A will be described as an example.

FIG. 2 is a schematic configuration block diagram of the coaxial transmission device.
The coaxial transmission device 10A is a device that performs Ethernet (registered trademark) communication, and is roughly classified into a network interface unit 11, a switch unit 12, a first modulation / demodulation device 13, and a first analog / digital converter (AD / DA). ) 14, a first transmitter / receiver 15, a second modem 16, a second analog-digital converter 17, a second transmitter / receiver 18, and a combiner / distributor 19.

  In the following description of the coaxial transmission device, for convenience, the case where data is transmitted from the network interface unit 11 side to the combiner / distributor 19 side is referred to as downlink, and conversely from the combiner / distributor 19 side to the network interface unit 11 side. A case where data is transmitted is called an uplink.

  The network interface unit 11 is configured as, for example, 1000BASE-T, and receives an Ethernet frame (= packet data) from the outside (in this case, the core network CNET) and outputs it to the switch unit 12 in the downlink. Further, at the time of uplink, the network interface unit 11 transmits the data output from the switch unit 12 to the outside (in this case, the core network CNET) as an Ethernet frame.

  The switch unit 12 filters (separates) PTP (Precision Time Protocol) packet data and other data at the layer 2 or layer 3 level from the Ethernet frame transmitted from the core network CNET output from the network interface unit 11 during downlink. Then, the PTP packet data is output to the second modem 16 and other packet data is output to the first modem 13. Further, at the time of uplink, the switch unit 12 outputs packet data other than the PTP packet output from the first modem unit 13 and the PTP packet data output from the second modem unit 16 to the network interface unit 11 as a series of packet data. .

  In this case, as a filtering method, there are a method of separating a PTP packet and a packet of a mobile communication terminal such as a mobile phone by a VLAN tag assigned on the core network CNET side, a method of separating by a UDP port number, or the like. Can be mentioned.

Here, the PTP packet data will be described.
The PTP packet data is data defined by IEEE 1588, and accurately transfers time information with high accuracy from a master clock serving as a reference of time information to a client clock via an asynchronous packet network.

By the way, in order to transfer highly accurate time information, it is necessary that the communication circuit has symmetry between the uplink and the downlink.
For this reason, in the present embodiment, the FDD wired transmission method is adopted for the communication of the PTP packet data.

FIG. 3 is an explanatory diagram of an example of frequency allocation to PTP packet data and other packet data.
For the PTP packet data, the first frequency band of the transmission center frequency f1 and the second frequency band of the reception center frequency f2 are allocated as transmission frequencies.
For other packet data, the third frequency band of the transmission / reception center frequency f3 is assigned as the transmission frequency in order to perform data communication by the TDD method.

  Furthermore, with regard to PTP packet data, considering the transmission rate in the uplink and downlink, the modulation rate is not changed and adaptive modulation (adaptive modulation) is not used. The modulation rate at the time of linking is the same. As a modulation method, for example, it is preferable to use a modulation method having a low modulation rate such as BPSK (Binary Phase Shift Keying) and a low error rate even with the same C / N (Carrier to Noise ratio). This suppresses retransmission due to the occurrence of an error. Furthermore, in the transmission / reception of PTP packet data, the transmission power is determined so as to obtain a desired C / N.

  In the downlink, the first modem 13 receives a signal other than PTP packet data from the switch unit 12 and converts it into a signal that can be transmitted via the coaxial cable based on the other packet data input. Modulate and output to the first analog-digital converter 14. Examples of the modulation scheme in this case include BPSK, QPSK (Quadrature Phase Shift Keying), 16QAM (16 Quadrature Amplitude Modulation), and 64 QAM (64 Quadrature Amplitude Modulation). The first modem 13 demodulates the other packet data input from the first analog-digital converter 14 into a signal that can be transmitted via the network interface unit 11 and outputs the signal to the switch unit 12 during uplink. .

  The first analog-to-digital converter 14 performs digital-analog conversion of the modulated signal output from the first modulation / demodulation device 13 and outputs it to the first transceiver 15 as a transmission signal at the time of downlink. The first analog-digital converter 14 performs analog-digital conversion on the received signal output from the first transmitter / receiver 15 and outputs the received data to the first modem 13 at the time of uplink.

  The first transmitter / receiver 15 is a transmitter / receiver that performs TDD transmission / reception using the third frequency band of the center frequency f3 described above, and generates a transmission signal and outputs it to the combiner / distributor 19 in the downlink. Further, at the time of uplink, the first transceiver 15 receives a reception signal corresponding to other packet data other than the PTP packet data distributed by the combiner / distributor and outputs the received signal to the first analog / digital converter 14.

  In the downlink, when the PTP packet data is input from the switch unit 12, the second modem 16 modulates the second analog / digital signal to a signal that can be transmitted via the coaxial cable based on the input PTP packet data. Output to the converter 17. As a modulation method in this case, a modulation method such as BPSK having a low modulation rate and a low error rate even with the same C / N can be cited. Further, at the time of uplink, the second modem 16 demodulates the PTP packet data input from the second analog-digital converter 17 into a signal that can be transmitted via the network interface unit 11 and outputs it to the switch unit 12.

  At the time of downlink, the second analog-digital converter 17 performs digital-analog conversion of the modulated signal output from the second modem device 16 and outputs it as a transmission signal to the second transceiver 18. The second analog-digital converter 17 performs analog-digital conversion on the received signal output from the second transmitter / receiver 18 and outputs the received data to the second modem 16 during uplink.

  The second transceiver 18 is a transceiver that performs FDD transmission / reception using the above-described first frequency band of the center frequency f1 and the second frequency band of the center frequency f2, and generates a transmission signal in the downlink. And output to the combiner / distributor 19. The second transmitter / receiver 18 receives a reception signal corresponding to the PTP packet data distributed by the combiner / distributor and outputs the received signal to the second analog / digital converter 17 during uplink.

  The combiner / distributor 19 synthesizes the transmission signal (frequency band of the center frequency f3) output from the first transceiver 15 and the transmission signal (frequency band of the center frequency f1) output from the second transceiver 18 during downlink. To the coaxial transmission device 10B via the coaxial cable. Further, at the time of uplink, the combiner / distributor 19 receives the received signal received from the coaxial transmission device 10B via the coaxial cable in the frequency band (frequency band of the center frequency f2) corresponding to the PTP packet data, and the PTP packet data. And the received signal of the frequency band (frequency band of the center frequency f3) corresponding to the PTP packet data is separated from the received signal of the frequency band (frequency band of the center frequency f3) corresponding to other packet data other than The received signal is output to the transmitter / receiver 18 and the received signal in the frequency band (frequency band of the center frequency f3) corresponding to the other packet data is output to the first transmitter / receiver 15.

  Therefore, in summary, the master device (not shown) of the core network CNET is the network interface unit 11 of the coaxial transmission device 10A → the switch unit 12 of the coaxial transmission device 10A → the second modulation / demodulation device 16 of the coaxial transmission device 10A → the coaxial transmission device. 10A second analog-digital converter 17 → second transmitter / receiver 18 of coaxial transmission apparatus 10A → combining distributor 19 of coaxial transmission apparatus 10A → coaxial cable → combining distributor 19 of coaxial transmission apparatus 10B → first of coaxial transmission apparatus 10B 2 transceiver 18 → second analog-digital converter 17 of coaxial transmission device 10B → second modulation / demodulation device 16 of coaxial transmission device 10B → switch unit 12 of coaxial transmission device 10B → network interface unit 11 of coaxial transmission device 10B in this order. Transmit PTP packet data to the radio base station BTS

  Similarly, the radio base station BTS moves from the network interface unit 11 of the coaxial transmission device 10B to the network interface unit 11 of the coaxial transmission device 10A in the reverse order to that described above with respect to the master device (not shown) of the core network CNET. To transmit the PTP packet data.

  A time synchronization processing procedure will be described by actually exchanging PTP packet data through the above-described PTP packet data transmission path.

FIG. 4 is an explanatory diagram of the time synchronization processing procedure by PTP.
First, at time t0, a master device (not shown) of the core network CNET transmits an announcement message AM for notifying time synchronization accuracy information to the radio base station BTS that is a slave device.

  Thereby, the radio base station BTS grasps that the time synchronization accuracy information is transmitted within a predetermined time thereafter.

Subsequently, at time t1, a master device (not shown) of the core network CNET transmits a sync message SM as an event message to the radio base station BTS.
In this case, a time t1, which is a transmission time of the sync message SM, is recorded in the sync message SM.

  At time t2, when the radio base station BTS receives the sync message SM, the radio base station BTS records the reception time t2.

Further, at time t3, the radio base station BTS transmits a delay request message (Delay_Request_Message) DRM to notify a master device (not shown) of the core network CNET that the sync message SM has been received.
In this case, the delay request message DRQM records a time t3 that is the transmission time of the delay request message DRM.

At time t4, when receiving the delay request message DRM, the radio base station BTS records the reception time t4.
Further, a master device (not shown) of the core network CNET transmits a delay response message (Delay Response Message) DRPM recording the reception time t4 of the delay request message DRM to the radio base station BTS.

Next, a method for calculating the time difference in the above state will be described.
Here, it is assumed that the clock time of the radio base station BTS and the clock time of the master device (not shown) of the core network CNET are shifted by the offset time TOF1.

  Therefore, in the case of the above-described example, the time difference from the master device (not shown) of the core network CNET to the radio base station BTS (slave) and the time difference from the radio base station BTS (slave) to the master device (not shown) of the core network CNET If the transmission delay time DLY1 is equal in any direction, the following relationship is established.

Time difference from the master device (not shown) of the core network CNET to the radio base station BTS (slave) direction t2−t1 = DLY1 + TOF1 (1)
Time difference from the radio base station BTS (slave) to the master device (not shown) of the core network CNET t4-t3 = DLY1-TOF (2)

  As a result, the radio base station BTS (slave) calculates the transmission delay time DLY1 from the sum of the equations (1) and (2), and the offset time TOF1 from the difference between the equations (1) and (2). Is calculated.

That is,
DLY1 = ((t2-t1) + (t4-t3)) / 2 (3)
TOF1 = ((t2-t1)-(t4-t3)) / 2 (4)
As a result, the radio base station BTS always performs time correction in the radio base station BTS based on the calculated transmission delay time DLY and offset time TOF1, thereby realizing highly accurate time synchronization. .

As described above, according to the first embodiment, the coaxial transmission device 10A and the coaxial transmission device 10B have the PTP packet data between the master and the slave asynchronously with other packet data transmitted in parallel. Can be transmitted via a transmission path different from other packet data, and the uplink and downlink can be transmitted symmetrically.
Therefore, highly accurate time synchronization can be performed and the state maintained.

[2] Second Embodiment The first embodiment described above is an embodiment in a higher-level communication network that is a communication network between a core network and a radio base station. In this embodiment, time synchronization is performed with a radio base station connected to the core network via a repeater device.

FIG. 5 is a schematic configuration block diagram of a repeater device according to the second embodiment.
In FIG. 5, for the sake of easy understanding, an example will be described in which a repeater device includes one master unit and two slave units connected to the master unit by a coaxial cable.

  The communication system 30 is roughly divided into a core network CNET, a first base station 31 directly connected to the core network, and both the core network CNET and the first base station via different communication paths. Master unit 32, two slave units 33-1 and 33-2 connected to the master unit 32 with coaxial cables, respectively, and a second base connected to the slave unit 33-1 via a communication network And a station 34.

  The main unit 32 is roughly classified into an RF interface (IF) 41, a frequency conversion unit 42, a first combiner / distributor 43, a network interface unit 44, a switch unit 45, a first modem unit 46, 1 analog-digital converter 47, first transceiver 48, second modem 49, second analog-digital converter 50, second transceiver 51, second combiner / distributor 52, and third modem 53, a third analog / digital converter 54, a third transceiver 55, a fourth modem 56, a fourth analog / digital converter 57, a fourth transceiver 58, a third combiner / distributor 59, It has.

Next, the slave unit 33-1 and the slave unit 33-2 will be described.
Here, since the subunit | mobile_unit 33-1 and the subunit | mobile_unit 33-2 are the same structures, the subunit | mobile_unit 33-1 is demonstrated as an example.

  The slave unit 33-1 can be broadly divided into a combiner / distributor 61, a frequency converter 62, a first transmitter / receiver 63, a first transmitter / receiver 63 connected to the second combiner / distributor 52 of the master unit 32 via a coaxial cable. 2 transceiver 64, first analog-digital converter 65, first modem device 66, third transceiver 67, second analog-digital converter 68, second modem device 69, switch unit 70, A network interface unit 71.

Next, an outline operation of the second embodiment will be described.
The radio signal transmitted from the core network CNET is a transmission signal in a corresponding frequency band (frequency band of the center frequency f4) in the path of the first base station 31 → the RF interface (IF) 41 → the first combiner / distributor 43, It is transmitted to the second combiner / distributor 52.

  On the other hand, among the packet data (PTP packet data and other packet data) directly transmitted from the core network CNET via the wired communication network, other packet data that is packet data to be transmitted to the slave unit 33-1 is: The frequency band corresponding to the other packet data is transmitted to the first modem 46 via the path from the network interface unit 44 to the switch unit 45, and further via the first analog-digital converter 65 and the first modem 66. The signal is transmitted to the second combiner / distributor 52 as a transmission signal having a frequency band of the center frequency f3.

  Of the packet data (PTP packet data and other packet data) directly transmitted from the core network CNET via the wired communication network, PTP packet data which is packet data to be transmitted to the slave unit 33-1 is The frequency band (center frequency) corresponding to the PTP packet data is transmitted to the second modem 49 via the path of the interface unit 44 → the switch unit 45, and further via the second analog-digital converter 68 and the second modem 69. The signal is transmitted to the second combiner / distributor 52 as a transmission signal in the frequency band of f1).

  As a result, the second combiner / distributor 52 combines the transmission signal of the frequency band of the center frequency f1, the transmission signal of the frequency band of the center frequency f3, and the transmission signal of the frequency band of the center frequency f4 to synthesize the slave unit 33-1. To be transmitted via a coaxial cable.

The combiner / distributor 61 of the child device 33-1 outputs the transmission signal in the frequency band of the center frequency f4 among the transmission signals received from the parent device 32 to the frequency converter 62.
The frequency converter 62 converts the communication frequency of a mobile terminal device (not shown) into communication with the mobile terminal device via the first transceiver 63 and an antenna (not shown).

  Further, the combiner / distributor 61 outputs a transmission signal (corresponding to other packet data) in the frequency band of the center frequency f3 among the transmission signals received from the parent device 32 to the second transmitter / receiver 64, and the second transmitter / receiver 64 64 outputs the received signal to the first analog-digital converter 65.

The first analog-digital converter 65 performs analog-digital conversion on the received signal output from the second transceiver 64 and outputs the received data to the first modem 66 as received data.
As a result, the first modem 66 demodulates the received data and outputs it to the switch unit 70 as other packet data.

  On the other hand, the combiner / distributor 61 outputs a transmission signal (corresponding to PTP packet data) in the frequency band of the center frequency f1 among the transmission signals received from the parent device 32 to the third transmitter / receiver 67. Outputs the received signal to the second analog-digital converter 68.

The second analog-digital converter 68 performs analog-digital conversion on the received signal output from the second transceiver 64 and outputs the received data to the second modem 69.
Thus, the second modem 69 demodulates the received data and outputs it to the switch unit 70 as PTP packet data.

  As a result, the switch unit 70 outputs the PTP packet data and other packet data to the second base station via the network interface unit 71.

  The above is a description of the case where PTP packet data is transmitted from a master device (not shown) of the core network CNET to the slave second base station. Next, the slave network of the core network CNET is transmitted from the second base station. An outline of operation when transmitting PTP packet data to a master device (not shown) will be described.

  When the second base station 34 transmits the PTP packet data to a master device (not shown) of the core network CNET, the network interface unit 71 → the switch unit 70 → the second modem device 69 → the second analog / digital converter 68. → 3rd transmitter / receiver 67 → synthetic distributor 61 → coaxial cable → second combiner / distributor of base unit 32 → second transmitter / receiver 51 → second analog / digital converter → second modem 49 → switch unit 45 → network interface The PTP packet data is transmitted to the master device (not shown) of the core network CNET in the order of the unit 44.

  As a result, the master device (not shown) of the core network CNET and the second base station 34 can maintain the state by performing highly accurate time synchronization according to the procedure shown in FIG.

  In the above description, the case where the frequency band (band) used for communication is constant has been described. However, different frequency bands are used for PTP packet data and other packet data, and the FDD method is used for PTP packet data. If an uplink transmission line and a downlink transmission line can be configured symmetrically by using them, an arbitrary frequency band can be appropriately used.

  The communication relay device of this embodiment includes a control device such as a CPU, a storage device such as a ROM (Read Only Memory) and a RAM, an external storage device such as an HDD and a CD drive device, a display device such as a display device, It has an input device such as a keyboard and a mouse, and has a hardware configuration using a normal computer.

  The program executed by the communication relay device of the present embodiment is provided by being recorded in a computer-readable recording medium such as a CD-ROM, DVD, or USB memory in an installable or executable format file. .

In addition, the program executed by the communication relay device of the present embodiment may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. Further, the program executed by the communication relay device of this embodiment may be configured to be provided or distributed via a network such as the Internet.
Further, the communication relay device program of the present embodiment may be provided by being incorporated in advance in a ROM or the like.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  For example, although the LTE signal has been taken up in the above description, the present invention can also be applied to other wireless communication signals such as a WiMAX signal and a wireless LAN signal.

DESCRIPTION OF SYMBOLS 10A, 10B Coaxial transmission apparatus 11 Network interface part 12 Switch part 13 1st modem apparatus 14 1st analog / digital converter 15 1st transmitter / receiver 16 2nd modem apparatus 17 2nd analog-digital converter 18 2nd transmitter / receiver 19 Synthesis distribution Unit 30 communication system 31 first base station 32 master unit 33 slave unit 34 second base station 42 frequency converter 43 first combiner / distributor 44 network interface unit 45 switch unit 46 first modem unit 47 first analog / digital converter 48 First transceiver 49 Second modulator / demodulator 50 Second analog-digital converter 51 Second transceiver 52 Second combiner / distributor 53 Third modulator / demodulator 54 Third analog-digital converter 55 Third transceiver 56 Fourth modulator / demodulator 57 4th analog-digital converter 8 Fourth transmitter / receiver 59 Third combiner / distributor 61 Combiner / distributor 62 Frequency converter 63 First transmitter / receiver 64 Second transmitter / receiver 65 First analog / digital converter 66 First modulation / demodulation device 67 Third transmitter / receiver 68 Second analog Digital converter 69 Second modem unit 70 Switch unit 71 Network interface unit BSC Base station controller BTS Wireless base station CNET Core network LC Coaxial cable

Claims (5)

A signal transmission apparatus that performs signal transmission in a TDD scheme,
A switch unit for separating a time synchronization signal and a signal other than the time synchronization signal included in the input transmission signal;
A first transmission path for transmitting a signal other than the time synchronization signal;
A second transmission path for transmitting the time synchronization signal;
Combining a transmission signal from the first transmission path and a transmission signal from the second transmission path side, and distributing a transmission signal to the first transmission path side and a transmission signal to the second transmission path side;
A signal transmission device comprising: The first transmission path includes a first modulation / demodulation device that modulates and demodulates signals other than the time synchronization signal, a first analog-digital converter that performs mutual conversion between an analog signal and a digital signal, and a first transceiver. Are serially connected,
The second transmission path includes a second modulation / demodulation device that performs modulation / demodulation of signals other than the time synchronization signal, a second analog-digital converter that performs mutual conversion between an analog signal and a digital signal, and a second transceiver. Are serially connected,
The signal transmission device according to claim 1. The second transmission path is configured to perform signal transmission by the FDD method.
The signal transmission device according to claim 2. A pair of signal transmission devices according to any one of claims 1 to 3 disposed opposite to each other via a communication cable;
A master device connected to one of the signal transmission devices and transmitting time synchronization accuracy information constituting the time synchronization signal;
A slave device connected to the other signal transmission device and performing time correction based on the time synchronization accuracy information;
Signal transmission system equipped with. A method executed by a signal transmission apparatus having a first transmission path for transmitting a signal other than a signal for time synchronization and a second transmission path for transmitting the signal for time synchronization, and performing signal transmission by the TDD method. There,
Separating the time synchronization signal and the signal other than the time synchronization signal included in the input transmission signal;
Transmitting a signal other than the time synchronization signal via the first transmission path;
Transmitting the time synchronization signal through the second transmission path;
Depending on the transmission direction, the transmission signal from the first transmission line and the transmission signal from the second transmission line side are combined, or the transmission signal to the first transmission line side and the transmission signal to the second transmission line side are distributed. The process of
With a method.

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