JPS622492B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention connects multiple information generation and reception points with an optical fiber cable that is commonly used for all information transmission, and uses this common optical fiber cable in a time-sharing manner. Therefore, the present invention relates to an optical fiber communication device that is capable of transmitting and receiving information between arbitrary information generation and reception points.

An example of this type of device is shown in FIG. 1 in the past. 2a, 2b in the figure
......, 2g is an optical branching coupler that enables signal transmission and reception between any optical fiber cables connected to it, and these are optical fiber cables 1a, 1
b, . . . 1h are connected in cascade. 3 is an optical switch connecting one end and the other end of the optical fiber transmission system formed as described above, 4 is a synchronizing signal generator, and 5 is a disconnection detector, and the output of this disconnection detector 5 is transmitted to the optical switch 3. Guided by and driven by. 6a, 6b, . Optical branch couplers 2a, 2b,...
..., 2g via optical fiber cables 1a, 1
b, ......, 1h.

Next, the operation of the optical fiber communication device shown in FIG. 1 will be explained. The synchronization signal generator 4 intermittently generates synchronization signals and supplies them to the disconnection detector 5 and the optical information transmission devices 6a, 6b, . . . , 6e. Each optical information transmission device 6a, 6b, ......, 6
e transmits its own transmission information intermittently while maintaining a constant time relationship determined for each optical information transmission device with the synchronization signal reception timing. At this time, each optical information transmission device 6a, 6b, The relative relationship between the signal sending timing of . . . , 6e and the synchronization signal timing is determined.

On the other hand, all the signals sent out in this way are transmitted through optical fiber cables 1b, 1c, 1
g and optical branching couplers 2a, 2b,......, 2g
All optical information transmission devices 6a, 6b,
......, 6e and the disconnection detector 5 are reached. Therefore, each optical information transmission device 6a, 6b, ......, 6
e is a signal sent to itself from among all received signals, using the relative time relationship between the synchronization signal and the received signal, the identification code provided in the received signal, etc. Separate and extract the components. The optical fiber communication device shown in FIG. 1 enables communication between arbitrary optical information transmission devices using the method described above.

Optical fiber cable 1b, 1c, ......, 1g
When a line is disconnected due to a failure, communication between all or some of the optical information transmission devices becomes impossible. When such a situation occurs, the disconnection detector 5 detects the occurrence of a disconnection fault by losing part or all of the signal reaching it, and generates a disconnection detection signal. The optical switch 3 receives this disconnection detection signal and changes the normally open state to a closed state. By changing the optical switch 3, normal communication can be continued. In addition, when continuing communication with the optical switch 3 in the closed state as described above, during that time,
In preparation for the occurrence of the next disconnection failure, it is desirable to quickly find the point of failure and repair the failure point so that the optical switch 3 can be opened again and communication can be performed.

Since conventionally known optical fiber communication equipment is configured as described above, a test signal transmission test is performed between adjacent optical information transmission equipment to find the fault point when repairing the fault point. There is a need,
For this reason, testing must be conducted at the locations of a large number of optical information transmission devices that are installed spatially apart, which has the disadvantage that the testing requires a great deal of effort and time. Additionally, during testing, special test equipment may be required to perform transmission tests without interfering with the signals being communicated at the time, or normal communication may need to be temporarily interrupted during testing. There were also some drawbacks.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and by providing a wire breakage position detector adjacent to a synchronization signal generator, it is possible to detect which optical information transmission device the wire breakage occurs when a wire breakage occurs. To greatly reduce the effort and time required to repair a point of failure by displaying whether a fault has occurred between the two, thereby providing an optical fiber communication device that is more reliable and easier to maintain. The purpose is to

An embodiment of the present invention will be described below with reference to the drawings.

In Fig. 2, 2a, 2b, ......, 2f are optical branching couplers, and these are optical fiber cables 1
They are connected by a, 1b, ......, 1h. Reference numeral 3 denotes an optical switch that connects one end and the other end of the optical fiber cable transmission system thus formed. Further, 4 is a synchronizing signal generator, 5 is a wire breakage detector, and 8 is a wire breakage position detector. Furthermore, 7 branches a part of the counterclockwise optical signal among the optical signals sent through the annular optical transmission lines 1a, 1b, 1h,
This is a unidirectional optical splitter that transmits information to the disconnection detector 5.
A disconnection detection signal, which is the output of the disconnection detector 5, is guided to a disconnection position detector 8, which is activated. The optical switch drive signal, which is the output of the disconnection position detector 8, is guided to the optical switch 3, and the optical switch 3, which is normally in an open state, is changed to a closed state. 6a, 6b,...
. . , 6e are spatially distributed optical information transmission devices, and communication, which is the purpose of the entire device, is carried out between these optical information transmission devices.

Next, the operation of the embodiment of the present invention shown in FIG. 2 will be explained. The manner of communication performed between each optical information transmission device is similar to that of the conventional optical fiber communication device described above. That is, each optical information transmission device transmits its own transmission signal while maintaining a fixed timing relationship with respect to the synchronization signal that is intermittently generated by the synchronization signal generator 4. At this time, the timing relationship is set so that the transmission signals generated by the plurality of optical information transmission devices do not overlap in time. Meanwhile, all of the signals generated in this way reach all optical information transmission devices through optical fiber cables. Each optical information transmission device separates and extracts the signal component transmitted toward itself from among the signals received in this manner.

If a disconnection fault occurs in the optical fiber cables 1b, 1c, . The occurrence of a disconnection fault is detected when all or part of the signals sent from the optical information transmitter 4 and the optical information transmission devices 6b, 6c, ......, 6e disappear, and the disconnection location is detected using the disconnection fault detection signal. It is sent out towards the container 8. When the disconnection position detector 8 receives the disconnection fault detection signal, it activates the synchronization signal generator 4 and the optical information transmission devices 6a, 6b, . . .
..., 6e, and sends a switching signal to the optical switch 3. This switching signal has the effect of converting the optical switch 3, which is normally open, to a closed state. By closing the optical switch 3, the optical information transmission device 6a, which has become inoperable due to a disconnection failure occurring in any one of the optical fibers 1b, 1c, . . . , 1g, is removed. 6b,...
..., 6e can restore normal communication between all or part of them. Here, the disconnection detector 5
and the disconnection position detector 8 is connected to the annular optical transmission line 1.
a, 1b, . Therefore, the reception status of the disconnection detector 5 and the disconnection position detector 8 is such that even after the optical switch 3 changes to the closed state and communication between each optical information transmission device is restored, the disconnection fault is removed. will be automatically retained.

On the other hand, when a disconnection fault occurs, the reception status of the signals sent from the synchronizing signal generator 4 and the optical information transmission devices 6a, 6b, . . . , 6e, which is displayed by the disconnection position detector 8, is as follows. It varies depending on which of the optical fiber cables 1b, 1c, . . . , 1g has a disconnection fault. For example, when the optical fiber cable 1b is disconnected, only the transmission signal of the synchronization signal generator 4 becomes unreceivable, and
When the optical fiber cable 1g is disconnected, the synchronization signal generator 4 and the optical information transmission devices 6a, 6b,...
All transmission signals from 6e are unreceivable.

In this way, there is a one-to-one correspondence between the optical fiber cable in which the disconnection fault has occurred and the signal reception status displayed by the disconnection position detector 8, and as described above, the state is different from the one in which the disconnection fault has occurred. Since it is held until it is removed, conversely, when a breakage fault occurs, the optical fiber cable that caused the breakage fault can be identified from the display contents of the breakage position detector 8.

In the above embodiment, the wire breakage detector 5, the synchronizing signal generator 4, and the wire breakage position detector 8 are provided to sandwich the optical switch 3, but they may be provided adjacent to each other. Further, in the above embodiment, an independent synchronization signal generator 4 for generating a synchronization signal is provided.
However, it is also possible to remove this and use the transmission signal of any one optical information transmission device selected from all the optical information transmission devices as the synchronization signal.
Further, the content displayed by the wire breakage position detector 8 does not have to be the signal reception state itself, and may be any wire breakage position information derived from the signal reception state.

As described above, according to the present invention, there is provided a disconnection position detector that detects the position of disconnection based on the receiving state of the signal sent through the unidirectional optical splitter provided in the circular optical transmission line. , When a disconnection fault occurs, the faulty optical fiber cable is automatically displayed, so that the fault point can be quickly searched and repaired after the fault has occurred, and the system is updated to locate the fault point. This eliminates the need to temporarily stop normal operation or prepare special testing equipment. Through these, it is possible to realize an excellent optical fiber communication system with high availability and operational reliability and low maintenance costs.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the structure of a conventional optical fiber communication device, and FIG. 2 is a block diagram showing the structure of an optical fiber communication device according to an embodiment of the present invention. 1a, 1b, ......, 1h... optical fiber cable, 2a, 2b, ......, 2g... optical branching coupler, 3... optical switch, 4... synchronization signal generator,
5...Disconnection detector, 6a, 6b,......, 6e...
...Optical information transmission device, 7... Unidirectional optical splitter, 8
...Disconnection position detector. In addition, the same symbols in the figure are
Indicates the same or equivalent part.

Claims (1)

[Claims] 1. A circular optical transmission line formed by connecting a plurality of optical fiber cables and a plurality of optical branching couplers in cascade, and connecting the start and end ends of the optical transmission line with an optical switch that is normally open, and the above-mentioned optical branching coupler. a plurality of optical information transmission devices coupled to the annular optical transmission line through a device; a disconnection detector that detects a disconnection failure occurring in the annular optical transmission line and switches the optical switch to a closed state; Optical fiber communication characterized by comprising a disconnection position detector that detects the position of disconnection based on the reception state of a signal sent from the annular optical transmission line via the unidirectional optical splitter when a disconnection failure occurs. Device.