JP4145778B2 - Optical communication system - Google Patents

Description

  The present invention relates to an optical communication system, and more particularly to an optical communication system including a master station device and a plurality of base station devices coupled by a bidirectional optical transmission line.

Conventionally, a power line maintenance monitoring system using an optical-fiber composite overhead ground wire (OPGW) has been provided in an electric power system. In the conventional transmission line maintenance monitoring system, the master station generates a control signal for controlling the uplink / downlink of each base station based on the location state of the terminal station capable of wireless communication with each base station, Transmit to each base station. The base station that has received the control signal demultiplexes the data signal and the control signal by the demultiplexer, and the control signal is input to the power supply control unit. The power supply control unit controls the downlink power amplification unit, the uplink low noise amplification unit, and the electric / optical converter according to the control signal (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 2001-112055

  However, the conventional power transmission line maintenance monitoring system generates a control signal for controlling the uplink / downlink of each base station based on the location state of the terminal station that can wirelessly communicate with each base station. There was a problem of becoming complicated.

  Therefore, a main object of the present invention is to provide an optical communication system having a simple configuration.

  An optical communication system according to the present invention is an optical communication system including a master station device and a plurality of base station devices coupled by a bidirectional optical transmission line. The master station device is turned on when the master station is transmitting and is turned off when the master station is received, and the base station device is connected to all base station devices via the optical transmission line during the period when the press talk switch is on. Signal generating means for outputting one optical signal, and master station transmitting means for transmitting a second optical signal including audio information to all base station apparatuses via an optical transmission line during a period in which the press talk switch is on. And a master station receiving means that is activated during a period in which the press talk switch is turned off and receives a third optical signal including audio information given from each base station apparatus via the optical transmission line. The base station apparatus is activated in response to the first optical signal from the signal generating means, and transmits a wireless signal corresponding to the second optical signal from the master station transmitting means to the wireless terminal existing in the wireless communication area. Activated during a period in which the first optical signal is not output from the signal generation means, receives a radio signal from a radio terminal existing in the radio communication area, and receives a radio signal corresponding to the received radio signal. And a base station transmitting means for transmitting the optical signal 3 to the master station receiving means via the optical transmission line.

  Preferably, the plurality of base station devices are divided into a plurality of systems, and the master station device further deactivates the radio transmission means of the base station of the selected system of the plurality of systems, Interference prevention means for preventing interference generated by a plurality of radio signals transmitted from a plurality of radio transmission means is provided.

  Preferably, the plurality of base stations are provided along the transmission line, the optical transmission path is an optical composite overhead ground line, and the optical communication system is used for maintenance monitoring of the transmission line.

  In the optical communication system according to the present invention, the master station device includes the first optical signal for control and the audio information to all the base station devices through the optical transmission line during the period when the press talk switch is on. The second optical signal is transmitted, and a third optical signal including audio information given from each base station device via the optical transmission line is received during a period in which the press talk switch is turned off. Therefore, bidirectional optical communication can be performed with a simple configuration.

  Further, the base station apparatus is activated in response to the first optical signal from the signal generating means, and a wireless terminal that has a wireless signal corresponding to the second optical signal from the master station transmitting means within the wireless communication area Activated in a period when the first optical signal is not output from the signal generating means, and receives a radio signal from a radio terminal existing in the radio communication area, and responds to the received radio signal. Base station transmitting means for transmitting the third optical signal to the master station receiving means via the optical transmission line. Therefore, since the base station transmission means is deactivated while the press talk switch is on, the second optical signal given from the master station device to the base station device is transmitted via the radio terminal and the base station device. The inconvenience of returning to the station apparatus can be prevented.

[Embodiment 1]
FIG. 1 is a diagram showing a configuration of a transmission line maintenance monitoring system according to Embodiment 1 of the present invention. In FIG. 1, this power transmission line maintenance and monitoring system includes a master station 2 provided at a power station 1 and an optical composite overhead ground wire 5 stretched from the master station 2 through a power station 3 to a plurality of power transmission line towers 4. A plurality of base stations 6 provided at predetermined intervals (1.5 to 3 km) along the optical composite ground wire 5, and a plurality of slave stations (wireless terminals) 7 that perform radio communication with the base station 6 Is provided. The optical composite aerial ground wire 5 extends over a power transmission line (not shown), and includes a ground line that protects the power transmission line from lightning, and an optical fiber provided inside the ground line. Each base station 6 is provided in a nearby transmission line tower 4. The slave station 7 is held by a power line maintenance supervisor. Each maintenance supervisor transmits the maintenance monitoring information of the power transmission line to the manager via the slave station 7, the base station 6, the optical composite overhead ground line 5 and the master station 2, and the administrator transmits the master station 2, the optical composite overhead ground. All maintenance managers are instructed via line 5, base station 6 and slave station 7.

  FIG. 2 is a block diagram showing the power transmission line maintenance monitoring system shown in FIG. 1 in more detail. In FIG. 2, the optical composite ground wire 5 includes an optical fiber 11 that constitutes a downlink, an optical fiber 12 that constitutes an uplink, and optical couplers (PCs) 13 provided corresponding to the respective base stations 6. 14 and the like. Each base station 6 is coupled to optical fibers 11 and 12 via optical couplers 13 and 14. The base station 6 includes an antenna 6a, and the slave station 7 includes an antenna 7a. The base station 6 and the slave station 7 perform wireless communication via the antennas 6a and 7a.

  FIG. 3 is a circuit block diagram showing the transmission line maintenance monitoring system shown in FIG. 2 in more detail, and FIG. 4 is a diagram showing the operation thereof. In FIG. 3, the master station 2 includes an information display operation unit 21, a microprocessor 22, a microphone 23, a press talk switch 24, a transmitter 25, a modulator 26, a multiplexer 27, an electric / optical converter 28, and an optical / electrical unit. A converter 29, a duplexer 30, a receiver 31, a demodulator 32, and a speaker 33 are provided.

  The press talk switch 24 is manually turned on / off by an administrator. The press talk switch 24 is turned on when the master station 2 is transmitting and is turned off when the master station 2 is receiving. The microphone 23 converts the administrator's voice into an electrical signal and gives it to the transmitter 25. The transmitter 25 is activated while the press talk switch 24 is turned on, and modulates a 150 MHz carrier wave with an electric signal from the microphone 23 and supplies it to the multiplexer 27. While the press talk switch 24 is on, the microprocessor 22 turns on the output of the T signal indicating that the master station 2 is transmitting and the R signal indicating that the master station 2 is receiving the voice. And the output of the R signal is turned on as well as the output of the T signal is turned off. The modulator 26 modulates the 10.8 MHz carrier wave with the T signal or R signal output from the microprocessor 22 and supplies the modulated signal to the multiplexer 27. The multiplexer 27 multiplexes the output signal of the transmitter 25 and the output signal of the modulator 26 and provides the combined signal to the electrical / optical converter 28. The electrical / optical converter 28 converts the electrical signal from the multiplexer 27 into an optical signal and outputs the optical signal to the optical fiber 11 as a downlink.

  The optical / electrical converter 29 converts the optical signal from the optical fiber 12 that is an uplink to an electrical signal and supplies the electrical signal to the duplexer 30. The demultiplexer 30 demultiplexes the electric signal from the optical / electrical converter 29 and gives it to the receiver 31 and the demodulator 32. The receiver 31 is activated while the press talk switch 24 is turned off, extracts an electrical signal including voice information of the maintenance supervisor from the 150 MHz electrical signal from the duplexer 30, and provides the speaker 33 with the electrical signal. The speaker 33 converts the electrical signal from the receiver into sound and transmits it to the administrator. The demodulator 32 extracts the monitoring information of the base station 6 from the 10.8 MHz electric signal from the branching filter 30 and supplies it to the microprocessor 22. The microprocessor 22 displays the monitoring information of the base station 2 on the display screen of the information display operation unit 21 according to the signal from the demodulator 32, and controls the entire master station 2 according to the instruction from the information display operation unit 21.

  The base station 6 includes an antenna 6a, an information monitoring controller 40, a changeover switch 41, a microprocessor 42, a modulator 43, a multiplexer 44, an electrical / optical converter 45, an optical / electrical converter 46, a duplexer 47, A demodulator 48 and a transmission amplifier 49 are provided.

  The optical / electrical converter 46 converts the optical signal given from the master station 2 through the optical fiber 11 and the optical coupler 13 into an electrical signal and gives it to the duplexer 47. The demultiplexer 47 demultiplexes the electric signal from the optical / electrical converter 46 and supplies it to the demodulator 48 and the transmission amplifier 49. The demodulator 48 extracts the T signal or R signal from the 10.8 MHz electrical signal from the duplexer 47 and supplies the extracted T signal or R signal to the microprocessor 42. The microprocessor 42 controls activation / deactivation of the transmission amplifier 49 according to a signal from the demodulator 48 and controls the changeover switch 41. The transmission amplifier 49 is controlled by the microprocessor 42 and is activated when the T signal is extracted by the demodulator 48, that is, when the prestalk switch 24 is turned on, and the 150 MHz electric signal from the duplexer 47. When the R signal is extracted by the demodulator 48, that is, when the press talk switch 24 is turned off, the signal is deactivated.

  The common terminal 41c of the changeover switch 41 is connected to the antenna 6a, one of the changeover terminals 41a is connected to the output node of the transmission amplifier 49, and the other changeover terminal 41b is connected to the multiplexer 44. The change-over switch 41 is controlled by the microprocessor 42. When the T signal is extracted by the demodulator 48, that is, when the press talk switch 24 is turned on, the terminals 41a and 41c are brought into conduction. Is extracted, that is, when the press talk switch 24 is turned off, the terminals 41b and 41c are electrically connected.

  The information monitoring control unit 40 gives the microprocessor 42 information related to the base station 6, for example, information on whether the base station 6 is operating normally, temperature, vibration, and the like. The microprocessor 42 converts information from the information monitoring control unit 40 into a data signal and supplies the data signal to the modulator 43. The modulator 43 modulates a 10.8 MHz carrier wave with a data signal from the microprocessor 42 and supplies the modulated signal to the multiplexer 44. The multiplexer 44 multiplexes the electric signal supplied from the antenna 6 a via the changeover switch 41 and the electric signal from the modulator 43 and supplies the combined signal to the electric / optical converter 45. The electrical / optical converter 45 converts the electrical signal from the multiplexer 44 into an optical signal and transmits it to the master station 2 via the optical coupler 14 and the optical fiber 12.

  The slave station 7 includes an antenna 7a and a transceiver 7b. The transceiver 7b extracts an electric signal including audio information from a 150 MHz radio signal transmitted from the antenna 6a of the base station 6 and received by the antenna 7a, and converts the extracted electric signal into audio to be a maintenance supervisor. introduce. The transceiver 7b converts the maintenance supervisor's voice into an electrical signal, modulates a 150 MHz carrier wave with the electrical signal, and transmits the modulated carrier wave to the base station 6 via the antenna 7a.

  Next, the operation of this transmission line maintenance monitoring system will be described. When transmitting the master station 2, the press talk switch 24 is turned on. As a result, the 10.8 MHz carrier wave of the modulator 26 is modulated by the T signal, and the carrier wave is demodulated by the demodulator 48 of the base station 6 through electrical / optical conversion, optical transmission and optical / electrical conversion, and the T signal is As detected by the microprocessor 42, the transmission amplifier 49 is activated, and the output node of the transmission amplifier 49 is coupled to the antenna 6a. The administrator's voice in the master station 2 is converted into an electric signal by the microphone 23 and given to the transmitter 25. The 150 MHz carrier wave modulated by the output signal of the microphone 23 is supplied to the transmission amplifier 49 of all base stations 6 through electrical / optical conversion, optical transmission and optical / electrical conversion, and transmitted to the slave station 7 via the antenna 6a. Is done. The slave station 7 converts the received radio signal into sound and transmits it to the maintenance supervisor.

  When the master station 2 receives a call, the press talk switch 24 is turned off. As a result, the 10.8 MHz carrier wave of the modulator 26 is modulated by the R signal, and the carrier wave is demodulated by the demodulator 48 of the base station 6 through electrical / optical conversion, optical transmission and optical / electrical conversion, and the R signal is As detected by the microprocessor 42, the transmission amplifier 49 is deactivated, and the antenna 6a is coupled to the multiplexer 44. A radio signal including the voice information of the maintenance supervisor is transmitted to the base station 6 via the antennas 7a and 6a, and is transmitted to the receiver 31 of the master station 2 through electrical / optical conversion, optical transmission and optical / electrical conversion. The sound is converted into sound by the receiver 31 and the speaker 33 and transmitted to the administrator.

  In the first embodiment, the master station 2 transmits an optical signal including audio information to all base stations 6 via the optical composite ground wire 5 during a period in which the press talk switch 24 is turned on. While the switch is off, an optical signal including audio information given from each base station 6 via the optical composite ground wire 5 is received. Therefore, bidirectional optical communication can be performed with a simple configuration at low cost.

Further, since the antenna 6a of the base station 6 and the electrical / optical converter 45 are disconnected while the press talk switch 24 is on, the optical signal given from the master station 2 to the base station 6 is transmitted to the slave station 7 and the base station. The inconvenience of returning to the master station 2 via 6 can be prevented.
[Embodiment 2]
In the first embodiment, when the press talk switch 24 is turned on, the output signal of the master station 2 is transmitted to all the slave stations 7 via all the base stations 6. At this time, radio signals from the two base stations 6 reach the slave station 7 located between the two adjacent base stations 6, and communication failure may occur due to interference between the two radio signals. In the second embodiment, this problem can be solved.

  FIG. 5 is a circuit block diagram showing a main part of a power transmission line maintenance monitoring system according to Embodiment 2 of the present invention, and is a diagram compared with FIG. Referring to FIG. 5, this transmission line maintenance monitoring system is different from the transmission line maintenance monitoring system of FIG. 3 in that a switch 50 is added to each base station 6. The switch 50 is connected between the antenna 6 a and the common terminal 41 c of the changeover switch 41 and is controlled by the microprocessor 42.

In this transmission line maintenance monitoring system, each base station 6 belongs to the A system or the B system. The odd-numbered base stations 6 as viewed from the master station 2 belong to the A system, and the even-numbered base stations 6 belong to the B system.
It is stored in the microprocessor 42 of the base station 6 whether each base station 6 belongs to the A system or the B system. The administrator in the master station 2 uses only the base station 6 of one of the A system and the B system or the A system and the B system using a changeover switch (not shown) of the information display operation unit 21. Both base stations 6 can be selectively activated.

  That is, as shown in FIG. 6, the microprocessor 22 of the master station 2 turns on the output of the A signal and B when the changeover switch of the information display operation unit 21 is instructed to activate only the A system. When it is instructed to turn off the signal output and activate both the A and B systems, the output of both the A and B signals is turned on, and when it is instructed to activate only the B system, the A signal And the output of the B signal is turned on. The output signal of the microprocessor 42 is supplied to the modulator 26. The 10.8 MHz carrier wave generated by the modulator 26 is modulated by a signal from the microprocessor 22, and is supplied to the demodulator 48 of all base stations 6 through electrical / optical conversion, optical transmission, and optical / electrical conversion. In the demodulator 48, the A signal and / or the B signal are extracted from the 10.8 MHz carrier wave and supplied to the microprocessor 42.

  The microprocessor 42 of the A-system base station 6 turns on the switch 50 when the A signal is given, and turns off the switch 50 when the A signal is not given. The microprocessor 42 of the base station 6 of the B system turns on the switch 50 when the B signal is given, and turns off the switch 50 when the B signal is not given.

  If no communication failure has occurred, the administrator activates both the base stations 6 of the A system and the B system using the changeover switch of the information display operation unit 21. In this case, the switches 50 of all base stations 6 are turned on, and the configuration is the same as in the first embodiment. In addition, when a communication failure has occurred, the administrator uses either the A system or the B system, for example, the base of the A system, using the changeover switch of the information display operation unit 21, as shown in FIG. Only station 6 is activated. In this case, the switch 50 of the base station 6 of the A system is turned on, and the switch 50 of the base station 6 of the B system is turned off. Thereby, the radio signal reaches only the base station 6 of the two base stations 6 to the slave station 7 located in the middle of the two adjacent base stations 6, and no communication failure occurs. .

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a figure which shows the structure of the power transmission line maintenance monitoring system by Embodiment 1 of this invention. It is a block diagram which shows the power transmission line maintenance monitoring system shown in FIG. 1 in detail. It is a circuit block diagram which shows the power transmission line maintenance monitoring system shown in FIG. 2 in further detail. It is a figure which shows operation | movement of the power transmission line maintenance monitoring system shown in FIGS. It is a circuit block diagram which shows the structure of the power transmission line maintenance monitoring system by Embodiment 2 of this invention. It is a figure which shows operation | movement of the power transmission line maintenance monitoring system shown in FIG. It is another figure which shows operation | movement of the power transmission line maintenance monitoring system shown in FIG.

Explanation of symbols

  1 power station, 2 master station, 3 electrical station, 4 transmission line tower, 5 optical composite ground wire, 6 base station, 6a, 7a antenna, 7 slave station, 7b transceiver, 11, 12 optical fiber, 13, 14 Optical coupler, 21 Information display operation unit, 22, 42 Microprocessor, 23 Microphone, 24 Press talk switch, 25 Transmitter, 26, 43 Modulator, 27, 44 Multiplexer, 28, 45 Electrical / optical converter, 29 , 46 Optical / electrical converter, 30, 47 duplexer, 31 receiver, 32, 48 demodulator, 33 speaker, 40 information monitoring control unit, 41, 50 switch, 49 transmission amplifier.

Claims (3)

An optical communication system comprising a master station device and a plurality of base station devices coupled by a bidirectional optical transmission line,
The master station device is
A press talk switch that is turned on when the master station is transmitting and turned off when the master station is receiving;
Signal generating means for outputting a first optical signal to all base station apparatuses via the optical transmission line during a period in which the press talk switch is on;
A master station transmitting means for transmitting a second optical signal including audio information to all base station apparatuses via the optical transmission line during a period in which the press talk switch is on; and A master station receiving means for receiving a third optical signal that is activated during each period and includes voice information given from each base station device via the optical transmission line;
The base station device
Activated in response to the first optical signal from the signal generating means, and transmits a wireless signal corresponding to the second optical signal from the master station transmitting means to a wireless terminal existing in a wireless communication area Activated in a period in which the first optical signal is not output from the radio transmission means, and the signal generation means, receives a radio signal from a radio terminal existing in the radio communication area, and responds to the received radio signal An optical communication system comprising base station transmission means for transmitting the third optical signal to the master station reception means via the optical transmission line. The plurality of base station devices are divided into a plurality of systems,
The master station device further deactivates a radio transmission unit of a base station of a selected system of the plurality of systems and causes interference caused by a plurality of radio signals transmitted from the plurality of radio transmission units The optical communication system according to claim 1, further comprising interference preventing means for preventing the interference. The plurality of base stations are provided along a power transmission line,
The optical transmission line is an optical composite overhead ground wire,
The optical communication system according to claim 1, wherein the optical communication system is used for maintenance monitoring of the power transmission line.

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