JPS5950626A - Fault locating system - Google Patents

Abstract

PURPOSE:To attain the fault locating without stopping signal from a counter terminal station device, by blocking a signal transmitted from the counter terminal station device in a relay device, when a monitor signal is transmitted to the relay device from a terminal station device. CONSTITUTION:Peak detecting circuits 121, 131, comparators 122, 132 and gates 123, 133 are provided in a monitor section 10. A signal transmitted from a gate 74 of a discriminating section 71 to the monitor section is set to a flip- flop 102 via a gate 101, transmitted to a filter 104 and also to a peak detecting circuit 121. The comparator 122 compares a received peak value with a set value and the gate 123 is opened at a preset value or over. When a monitor signal is transmitted in this case, an output from the comparator 105 blocks a gate 76 of the discriminating section 72 via the gate 123 so as to prevent a signal transmitted from an equalizing amplifier shown in Figure from being transmitted to a reproducing section 91.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a fault detection method, in particular, a failure detection method in which a plurality of relay devices are inserted into a pair of transmission paths connecting both end station devices, and monitoring means for transmitting a monitoring signal of a predetermined frequency previously assigned to each relay device, which is transmitted to each relay device via a transmission path in one direction, to the terminal device via a transmission path in the other direction; The present invention relates to a failure search method in a relay transmission system provided in each of the relay devices.

(bl Technical Background FIG. 1 is a diagram showing an example of a relay transmission system to which the present invention is applied, and FIG. 2 is a diagram showing an example of the configuration of a relay device in FIG. 1. , a pair of transmission lines 3 and 4 connect the terminal equipment 1 and 2, and the terminal equipment 1
The transmission path 3 transmits the main signal from the terminal device 2 to the terminal device 2, and the transmission path 4 transmits the main signal from the terminal device 2 to the terminal device 1, respectively. A plurality of relay devices 5 are inserted into the transmission lines 3 and 4.

Each relay device 5 includes an uplink repeater 51 inserted into the transmission path 3.
and a downlink repeater 52 inserted into the transmission path 4. In FIG. 2, the uplink repeater 51 is
The main signal in digital format arriving from -1 is amplified by the equalizing amplifier 61, and the clock extracting section 81
Based on the clock signal clk extracted from the output of the equalizing amplifier 61 , the identifying section 71 identifies the logical value of the output of the equalizing amplifier 61 and transmits it to the reproducing section 91 . The reproducing unit 91 reproduces the main signal based on the transmitted identification result and sends it to the transmission path 3-2. In the downlink repeater 52, the equalizing amplifier 62, the identification section 72, the clock extraction section 82, and the regeneration section 92 operate in the same manner, and transfer the digital main signal coming from the transmission path 4-1 to the transmission path 4-2. Replay and broadcast. - When the station device 1 or 2 detects a failure in the relay transmission system, it sends a monitoring signal of a predetermined frequency f1 previously assigned to each relay device 5 to the transmission path 3 or 4. In the relay device 5, the monitoring unit 10 monitors the identification result output from the identification unit 71 or 72, and if the monitoring signal of the frequency f1 assigned to the own relay device 5 is detected, it reproduces the monitoring signal. Part 92
Alternatively, it is sent to the transmission path 4-2 or 3-2 via 91, and is returned to the terminal device 1 or 2 from which the monitoring signal was sent. The terminal device 1 or 2 determines the normality of the corresponding relay device 5 and the transmission lines 3 and 4 leading to the relay device 5, depending on whether or not the monitoring signal is returned. By carrying out the above process for each relay device 5, the terminal device 1 or 2 searches for a troubled location in the relay transmission system.

(C1 Conventional technology and problems FIG. 3 is a diagram showing an example of a conventional fault search method.

In FIG. 3, only part of the monitoring section 10 in the relay device 5, identification sections 71 and 72, and reproduction sections 91 and 92 related to the monitoring section 10 are shown. The main signal or monitoring signal (hereinafter, the main signal and the monitoring signal are collectively referred to as signals) transmitted from the equalization amplifier 61 (not shown) is as follows:
The signal is set in the flip-flop 73 in the identification section 71 and transmitted to the reproduction section 91 and the monitoring section 10 via the gate 74. The main signal or monitoring signal transmitted to the reproduction section 91 is
The signal is transmitted to the laser diode drive circuit 94 via the gate 93, and is sent to the transmission path 3=2 (not shown) by driving the laser diode 151. Also gate 7
The signal transmitted from game 1-101 to monitoring unit 10
The signal is set in the flip-flop 102 via the amplifier circuit 103, and is then amplified by the amplifier circuit 103 and transmitted to the filter 104.

The filter 104 extracts only the monitoring signal of the frequency f1 assigned to the self-relay device 5, and transmits it to the comparator 105. The comparator 105 compares the peak value of the transmitted monitoring signal with a preset darkness value, and when the darkness value is exceeded, the laser deterioration detection circuit 96 detects the laser diode 151.
Unless an abnormality is detected and a failure detection signal is transmitted to the gate 106, the gate 1-106 is kept in a conductive state. the result,
When the monitoring signal of the frequency f1 is output from the gate 74, the monitoring signal is transmitted to the reproducing unit 92 via the gates 101 and 106, and is transmitted via the gate 97, the laser diode drive circuit 98, and the laser diode 152. The signal is sent to a transmission path 4-2 (not shown). Note that at this time, if a signal is being transmitted from the equalization amplifier 62 (not shown),
Through the same process as described above, this signal is also transmitted to the reproduction section 92 via the identification section 72, and is superimposed on the monitoring signal transmitted from the monitoring section 10.
-2 cannot be distinguished from the monitoring signal. Therefore, when the terminal device 1 (not shown) sends a monitoring signal to the transmission path 3, normal failure detection becomes impossible unless the terminal device 2 stops sending the signal to the transmission path 4. . Similarly, when sending a monitoring signal from the terminal device 2 (not shown) to the transmission path 4, normal failure detection is impossible unless the sending of the signal from the terminal device 1 to the transmission path 3 is stopped. .

As is clear from the above explanation, in the conventional fault detection method, when transmitting a monitoring signal from the terminal device 1 or 2 to detect a fault in the relay device 5 and the transmission lines 3 and 4, the There was a drawback that the signal from the terminal device 2 or 1 had to be stopped.

(d) Object of the Invention The object of the present invention is to eliminate the drawbacks of the conventional fault detection method as described above, and to provide a fault detection method that allows fault detection using a monitoring signal without stopping the signal from the opposite end station device. It lies in realizing the method.

tel Structure of the Invention This object is to insert a plurality of relay devices into a pair of transmission paths connecting both end station devices, and to transmit data from one of the end station devices to each of the relay devices via a unidirectional transmission path. In a relay transmission system, each of the relay devices is provided with a monitoring means for returning a monitoring signal of a predetermined frequency assigned to each of the relay devices in advance to the terminal device via a transmission path in the other direction,
The monitoring means, which commonly includes a filter for extracting the monitoring signal received from the transmission paths in each direction, is provided with means for determining the direction of the transmission path from which the monitoring signal arrives, and This is achieved by providing the relay device with means for preventing relay of the main signal in the direction opposite to the arrival direction of the monitoring signal.

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

FIG. 4 is a diagram showing a fault search method according to an embodiment of the present invention. Note that the same reference numerals refer to the same objects throughout the plan. In FIG. 4, peak detection circuits 121 and 131, comparators 122 and 132, and gates 123 and 133 are provided in the monitoring section 10. As illustrated in FIG. Peak detection circuit 1
21 as well. The peak detection circuit 121 detects the peak value of the received signal and transmits it to the comparator 122. The comparator 122 compares the received peak value with a preset threshold value, and if it exceeds the dark value, turns the gate 123 on.

Therefore, when the monitoring signal of frequency f1 assigned to the relay device 5 is transmitted from the gate 74, the comparison output output from the comparator 105 passes through the gate 123 to the gate 76 of the identification unit 72. A blocking state is set, and the signal transmitted from the equalizing amplifier 62 (not shown) is prevented from being transmitted to the reproducing section 91. Therefore, the monitoring signal of frequency f1 sent from the terminal device 1 to the transmission line 3 for fault searching is not interfered with by the signal sent from the terminal device 2', and is transmitted to the monitoring section 10 and the reproducing section. The signal is sent out to a transmission line 4-2 (not shown) via 92 and returned to the terminal device 1. Similarly, the monitoring signal of frequency f1 sent from the terminal device 2 to the transmission path 4 for fault searching is transmitted to the monitoring section 10 and the reproducing section 9 without being interfered with by the signal sent from the terminal device 1.
1 to a transmission FIP f3-2 (not shown),
It is sent back to the terminal device 2.

As is clear from the above description, according to this embodiment, the monitoring signal of frequency f1 is transmitted from the terminal device 1 or 2 to the relay device 5.
When the signal is transmitted from the opposite terminal device 2 or 1, the signal sent from the opposite terminal device 2 or 1 is automatically blocked within the relay device 5, so that the signal from the opposite terminal device 2 or 1 is not stopped. , it becomes possible to search for failures.

It should be noted that FIG. 4 is only one embodiment of the present invention, and includes, for example, the monitoring section 10, the identification sections 71 and 72, and the reproduction section 9.
The configurations of 1 and 92 are not limited to those shown in the drawings, and many other modifications may be considered, but the effects of the present invention will not change in any case.

(gl) Effects of the Invention According to the present invention, in the relay transmission system, it is possible to realize a fault detection method capable of detecting a fault using a monitoring signal without stopping the signal from the opposite end station device. becomes.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a relay transmission system to which the present invention is applied, FIG. 2 is a diagram showing an example of the configuration of the relay device in FIG. 1, and FIG. 3 is a diagram showing an example of a conventional fault detection method. FIG. 4 is a diagram showing a failure detection method according to an embodiment of the present invention. In the figure, 1 and 2 are terminal devices, 3 and 4 are transmission lines, 5 is a repeater, 51 is an uplink repeater, 52 is a downlink repeater, 61 and 62 are equalization amplifiers, 71 and 72 are identification units, 81 and 82 are clock extraction parts, 91 and 9
2 is a playback section, 10 is a monitoring section, 73.75.102 and 112 are Frisob flops, 74.76.93.97.
10], 106.107.111.123 and 133
is a gate, 94 and 98 are laser diode drive circuits, 95 and 90 are drivers, 96 and 99 are laser deterioration detection circuits, 104 is a filter, 105.122 and 132 are comparators, 121 and 131 are peak detection circuits, 151 and 152 indicate a laser diode. 1 3 1 prison 2 prison 3 m

Claims (1)

[Claims] A plurality of relay devices are inserted into a pair of transmission paths connecting both end station devices, and the transmission is transmitted from one of the end station devices to each of the relay devices via a unidirectional transmission path. In a relay transmission system, wherein each relay device is provided with a monitoring means for returning a monitoring signal of an assigned predetermined frequency to the terminal device via a transmission path in the other direction, wherein the monitoring signal is received from the transmission path in each direction. The monitoring means, which commonly includes a filter for extracting the monitoring signal, is provided with means for determining the direction of the transmission line in which the monitoring signal arrives, A fault detection method characterized in that the relay device is provided with means for preventing signal relay.