JPH053938B2 - - Google Patents

Description

Circuit means 13 for correcting code errors A fault point locating method characterized by:

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a fault point locating method for locating a fault point in an optical fiber multi-repeater transmission system or the like.
In particular, the present invention relates to a fault point locating method that performs location by making a loopback connection and can accurately locate whether a faulty relay point is located on an upstream or downstream transmission path.

〔overview〕

The present invention provides a fault point locating method in which a fault search signal is sent back from one station to a relay point to be located using an optical fiber multi-relay transmission system, and the fault search signal is measured to locate the fault point. By correcting code errors in the fault search signal when it is looped back from the relay board on the downlink transmission path to the relay board on the uplink transmission path at the relay point, and detecting errors in the sending pattern and coding rules of this fault search signal. , it is possible to locate a faulty relay point, and also to accurately determine whether the faulty location is on an upstream or downstream transmission path.

[Conventional technology]

When a fault occurs in an optical fiber multi-repeater transmission line, one way to search for the faulty repeater or transmission line is to sequentially return the fault search signal sent from the station at the repeater and detect errors in the transmission pattern. There is a centralized monitoring method that measures and locates failure points.

FIG. 2 is a block diagram showing a failure point locating system in such a conventional relay transmission system. Bandpass filters 10 with different passbands are connected to the relay board 6 at each relay point, and the output of the bandpass filter 10 is connected to a signal return control circuit 11 that controls the signal switching circuits 8 and 9. . Normally, the signal switching circuits 8 and 9 are oriented in the direction of the solid arrow, and signals are not folded back.

If a fault occurs in a relay board or transmission line, locate the fault point as follows. A fault search signal is sent from the fault search signal generator 4 of the station 1,
At each repeater board 6, an audio band frequency component is extracted by a low-pass filter or simple code conversion means, and further, an audio band frequency component assigned to each relay board 6 to be located is extracted by a bandpass filter 10. The extracted voice band frequency component causes the signal return control circuit 11 to operate, and the signal switching circuits 8 and 9 to switch in the direction of the broken line arrow in FIG.

By switching the signal switching circuits 8 and 9, the signal is returned to the relay board 7 in the opposite direction at each relay point and returned to the fault search signal measuring device 5 of the station 1. In this way, the point of failure can be located by monitoring, at station 1, errors in the transmission pattern of the failure search signals that are successively returned from relay points closer to station 1.

[Problem that the invention seeks to solve]

However, with such conventional fault location methods, the fault detection signal measuring device's location results are the same regardless of whether the fault is on the upstream or downstream transmission line, and the fault location results are the same whether the fault is on the upstream or downstream transmission line. There was a problem where it was impossible to distinguish whether there was a failure point or not.

The present invention solves these conventional problems and aims to provide a fault point locating method that can distinguish and locate whether a fault point is located on an uplink or a downlink.

[Means for solving problems]

The present invention provides a repeater board provided at each relay point on a downlink transmission path and an uplink transmission path, a signal switching circuit that returns a downlink signal to an uplink transmission path at each relay point, and a signal switching circuit connected to the relay board on the downlink transmission path. circuit means for extracting a control signal addressed to each relay point from the downlink signal, and a signal return control circuit for controlling switching of the signal switching circuit by the output of this circuit means, and the control signal is returned at each relay point. In a fault point locating method that includes a means for detecting errors in a signal transmission pattern and locating a fault point, a connection is made between the output end of the relay board of the downlink transmission line and the input end of the relay board of the uplink transmission line. The present invention is characterized by comprising circuit means for correcting a code error in a signal returned by switching the signal switching circuit.

[Effect]

The present invention transmits a fault search signal that is looped back at a relay point to be located from one station, and when the fault search signal is looped back from a relay board on a downlink transmission path to a relay board on an uplink transmission path at each relay point, the code error occurs. By correcting the fault detection signal and measuring errors in the transmission pattern and coding rule of the fault detection signal at the station that sent the fault detection signal, it is possible to locate the fault point and determine whether the fault point is located in the upstream or downstream direction. It is possible to accurately locate the location on the transmission path.

That is, if there is a fault on the downlink transmission path, an error in the transmission pattern will be detected, but an error in the coding rule will not be detected. Furthermore, if there is a fault on the uplink transmission path, both an error in the transmission pattern and an error in the coding rule are detected.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. In FIG. 1, a downlink transmission line 2 for transmitting downlink signals from the station 1 and an uplink transmission line 3 for transmitting uplink signals to the station 1 are connected to the station 1. In the station 1, a fault detection signal generator 4 connected to the downlink transmission line 2 and a fault detection signal measuring device 5 connected to the uplink transmission line 3 are arranged. A relay board 6 and a signal switching circuit 8 are connected to the down transmission line 2 at each relay point, and a relay board 7 and a signal switching circuit 9 are similarly connected to the up transmission line 3. A signal return control circuit 11 is connected to each repeater board 6 via bandpass filters 10 having different passbands. The signal switching circuits 8 and 9 have a structure in which the output side of the repeater board 6 and the input side of the repeater board 7 are switched to be connected via the return transmission line 12 by the output of the signal return control circuit 11. The signal is looped back to the station 1 via the upstream transmission line 3.

The feature of the present invention is that a code error correction circuit 13 is inserted into the return transmission line 12, and a fault search signal generator 4
The purpose of this is to correct code errors when returning the fault search signal sent from the source.

In normal communication, the signal switching circuits 8 and 9 are oriented in the direction of the solid arrow, and the signals sent to the downlink transmission line 2 are not looped back.

Here, in order to search for a fault at each relay point, if the station 1 sends out a fault search signal with a bandpass component possessed by the bandpass filter 10 of the relay board 6 to be located, the relay board 6 The connected signal loopback control circuit 11 operates, switches the signal switching circuits 8 and 9 in the direction of the broken line arrow, and loops back the fault search signal.

In other words, relay boards 6 and 7 or transmission lines 2 and 3
When locating whether or not a fault has occurred in the relay board 6, if the station 1 sends out a fault search signal with a bandpass component that the bandpass filter 10 has, The audio band frequency component is extracted by means etc., and the audio band frequency component assigned to the relay board 6 to be located is extracted by a band pass filter 10.
Extracted by Based on the extracted audio band frequency component, the signal return control circuit 11 operates and the signal switching circuits 8 and 9 are switched in the direction of the dashed arrow. By this switching, the fault search signal is returned to the relay board 7 in the opposite direction at the relay point where the fault search signal was located, and is inputted to the fault search signal measuring device 5 of the station 1.

At this time, the code error correction circuit 13 corrects the error in the code rule that occurred in the downlink transmission line 2 or the repeater board 6 in the fault search signal returned by the switching of the signal switching circuits 8 and 9.

Therefore, the fault search signal measuring device 5 of station 1 measures errors in the transmission pattern and coding rules of the fault search signal to determine whether a fault has occurred at any relay point, either in the downlink or the uplink. It is possible to detect whether

That is, if a fault occurs in the downlink transmission line 2 or the downlink of the relay board 6, an error in the sending pattern of the fault search signal sent from the fault search signal generator 4 of the station 1 will be detected. , no error in the sign rule is detected. Further, if a fault occurs in the uplink transmission line 3 or the uplink of the relay board 7, an error in the sending pattern of the fault search signal is detected, and an error in the coding rule is also detected.

〔Effect of the invention〕

As explained above, the present invention can accurately locate which relay point on an uplink or downlink transmission path has a fault, and it is easy to identify the fault point in optical fiber multi-repeater transmission systems. become,
This has the excellent effect of allowing quick repair and maintenance.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention. FIG. 2 is a block diagram showing a conventional fault point locating method. 1... Station, 2... Downlink transmission line, 3... Uplink transmission line, 4... Fault search signal generator, 5... Fault search signal measuring device, 6, 7... Relay board, 8, 9... Signal switching circuit, 10...Band pass filter, 11...
...Signal return control circuit, 12...Return transmission line,
13... Code error correction circuit.

Claims (1)

[Scope of Claims] 1. Relay boards 6, 7 provided at each relay point of the down transmission line and up transmission line, and signal switching circuits 8, 9 for returning the down signal to the up transmission line at each relay point, circuit means 10 which is connected to the relay board on the downlink transmission path and extracts a control signal addressed to each relay point from the downlink signal; and a signal return control circuit 11 which controls switching of the signal switching circuit based on the output of this circuit means. In a fault point locating method comprising a means for locating a fault point by detecting an error in the sending pattern of the signal returned at each relay point, The sign of the signal that is connected between the input terminals of the relay board of the road and is folded back by the switching of the signal switching circuit described above.