JPH03270522A - Sv signal propagation control system - Google Patents

Abstract

PURPOSE:To make the processing of an SV(supervisor) signal proper and to prevent production of malfunction by checking an address of the SV signal at an SV execution section of a controlled object repeater and stopping the output of the SV signal when the address is coincident with its own address. CONSTITUTION:An address 2 entering a shift register 31 is compared with an address of an controlled object repeater by an address comparator 37. In the case of dissidence, a transmission direction switch 36 is used to send an SV instruction signal in a similar format to its own line. When the address is coincident with its own address, the address comparator 37 activates an attribute decoding section 38. The decoding section 38 decodes an attribute 4 in the shift register 31 and opens a gate 39 when it is an instruction to send a data part 3 form the shift register 31 to a decoder 29. Then the instruction is decoded by the decoder 29 to allow an SV operating section 30 to execute the instruction. The processing of the SV instruction is terminated up to the section 30 and no loopback of the SV instruction signal takes place.

Description

[Detailed Description of the Invention] [Summary of the Invention] Regarding the SV multiplication signal propagation control method in an optical communication system, the purpose of this invention is to appropriately process the SV multiplication signal during loopback to prevent malfunctions. In an optical communication system, an amplification type repeater is inserted into an optical fiber to form a transmission line, and an SV multiplied signal is propagated along with the main signal on the transmission line, and during testing, it is looped back with a repeater following the controlled repeater. In the SV double signal propagation control method, the SV execution unit of the controlled repeater whose address of the SV command signal matches its own address is configured to stop sending out the SV command signal.

[Industrial Application Field] The present invention relates to an SV multiplication signal propagation control method in an optical communication system.

In an optical direct amplification type optical submarine relay using an erbium-doped fiber, an SV (supervisor) command is sent by AM modulation of an optical signal. Furthermore, in a communication system that includes a repeater, a loopback is performed to identify a fault location, and the present invention deals with problems related to SV multiplied signal propagation in such a system.

[Conventional technology]

When an SV command is sent by AM modulation of an optical signal in an optical relay transmission system, the propagation of the SV command is hindered by the AGC operation of the repeater (the amplitude of the optical signal is averaged by AGC, the modulation degree is lowered, and multiple repeaters are not possible). Therefore, we have proposed a solution to this problem.

The outline will be explained with reference to FIG. 4. l is an optical fiber, and the dotted line is erbium doped. HM is a half mirror
1LD is a laser diode, these are preamplifier 11
to the bottom of the tank. Namely, laser diode LD, half mirror
Bumping light is sent to an erbium-doped optical fiber using HM, causing stimulated emission and direct amplification of the light. next 12
is the SV multiplied signal extraction section, which extracts a part of the preamplified light with a half mirror, converts it into an electrical signal with the optical/electrical converter 0/E, and passes it through the BPF that passes the SV multiplied signal frequency fsv.
It leads to the V execution unit 12a. The next step 13 is an AGC amplifier that guides the optical signal in the optical fiber to O'/E with a half mirror, amplifies it with amplifier 13a, converts it to E10 with LD, injects the bombing light into the optical fiber with a half mirror, and converts the optical signal into the optical fiber. AGC amplification is performed to keep the amplitude of the optical signal constant. The next numeral 14 is a post-amplifier, which inserts the SV multiplied signal separated at 12 into the optical fiber again (amplitude modulates the SV multiplied optical signal). These are the upstream repeaters ([IP REP)
, and 20 is a downstream repeater (DOWN R
EP), 15 is a power supply unit that supplies power to these repeaters.

At the bottom of this tank, the SV double signal is separated in front of the AGC amplifier,
Since it is reinserted after the AGC amplifier, there are no problems with amplitude averaging or SV signal attenuation in the AGC amplifier.

In Fig. 4, the up and down directions are shown separately, but this can also be changed to -Shukoku, and this example is shown in Fig. 5.

Upstream and downstream signals pass through the optical fiber 13a
13b is the amplifier for upstream AGC, and 13b is the downstream AGC.
This is an amplifier for. The upstream/downstream SV multiplied signal frequencies are changed to f and □ on one side and fsv□ on the other side. The chain line frame 16 is shown in Figure 6, and is half mirror HM.
Extract the upstream signal on one side, and extract the downstream signal on the other side,
These are converted by the respective optical/electrical converters 07E, converted into electrical signals, and guided to the filter and further to the SV execution section 12c.

[Problem to be solved by the invention]

In the previously proposed device, the SV multiplied signal is relayed and output as is (to put it simply, it passes through the repeater). Therefore, if loopback is applied to a repeater after a repeater that is subject to SV (monitoring) control, the loopback will loop back to the target repeater and the delayed SV multiplied signal will enter the paired line. . That is, as shown in Fig. 7, the terminal station (
An optical transmission line with a large number of repeaters R1, R2, etc. inserted between land stations (land stations) is installed, and in order to identify faults, etc., loopback is performed with the subsequent repeater R3, and a loop is created between R2 and R3. However, when repeater R2 directly sends out the SV command sent by the land station, repeater R3 loops it back and returns it to repeater R2.

The SV double signals include various command signals such as error count requests issued from the land station and response signals from repeaters. SV commands such as error count requests include the address of the repeater that should execute the command, and each repeater checks the address of the SV command and executes the command if it matches its own address. . When the repeater (referred to as R2) that executed the command sends out the SV command, and the subsequent repeater (referred to as R3) performs loopback, the SV command is loop-banked in the repeater R3, It enters repeater R2 a little later. This SV
Since the address of the command matches the address of repeater R2, repeater R2 will execute the command again. In the above error count, count start,
Three types of SV commands are sent: same stop and count value sending, but when repeater R2 starts counting the pit error rate at the first count start, the count start is looped back and restarted after a little delay. , the repeater R2 performs a reset and restart, and the amount counted up to now disappears.

The present invention aims to improve this point, and aims to properly process the SV signal during loopback to prevent malfunctions.

[Means to solve the problem]

As shown in FIG. 1(a), in the present invention, the SV execution unit 12a of the controlled repeater checks the SV double signal address, and if it matches its own address, stops outputting the SV double signal.

In addition, in the present invention, as shown in FIG. 1(b), the SV execution unit 12a of the loopback repeater checks the signal format attribute and loops back if it is a response signal.
If it is a command signal, stop sending it.

As in all figures, parts that are the same as in other figures are given the same reference numerals. Therefore, 11 is the preamplifier, 12 is the S
13 is an AGC amplifier, and 14 is a post amplifier (SV signal insertion section). Further, IO is an upstream repeater, and 20 is a downstream repeater.

[Effect]

The optical signal transmitted within the optical fiber has a main signal and an SV multiplied signal, and although they pass through a preamplifier together, the SV
The extraction unit 12 separates the signal, and only the SV signal enters the SV execution unit 12a. Although both the main signal and the SV multiplied signal enter the AGC amplifier 13, the SV multiplied signal is attenuated due to amplitude equalization. Therefore, as shown in FIG. 1(a), the SV execution unit 1
2a compares the address of the SV signal with its own address,
If they match, if you just execute the SV signal command and do not send it to the post amplifier I4, the SV double signal will not be output from the controlled repeater and loopback will be performed in the subsequent repeater. Even if the SV double signal addressed to itself is not returned.

This method of stopping the SV multiplication signal destined for the repeater at the controlled repeater is a problem in systems that prepare simultaneous execution commands (loopback off, simultaneous error count for each repeater, etc.) using a common address for all repeaters. It is. That is, the first repeater stops sending this command, and it is not transmitted to subsequent repeaters.

For this purpose, it is effective to check the signal attributes in the loopback repeater shown in FIG. 1(b) and stop the SV signal at the SV execution section of the loopback repeater. Even with this, the SV double signal will not be healed back to the controlled repeater, and the command signal using the common address for all repeaters will also be
It can be transmitted to all repeaters up to the loopback repeater. This operation is performed only while the loopback is valid, and when the loopback is released, the signal is sent through the SV double signal repeater.

[Example] Figure 2(a) shows the difference between FIG. 1(a), and FIG.
An example of (b) is shown below. In both cases, only the SV execution unit 12a is shown. Further, FIG. 2(b) shows the SV double signal format.

SV double signal ■rsv synchronization, ■SV address, ■
It consists of SVi11m command data or SV response data, ① attribute (indicates whether it is a command or a response, and if it is a response, the transmission direction is the own line or the paired line), ② parity, and ② separator. The synchronizer detects the SV double signal, synchronizes, and resets the internal register, and the separator 2 indicates the end of the SV double signal.

As shown in FIG. 2(a), the SV execution section includes an SV operation section 30, a shift register 31, an ECL-01 (TTL) level conversion section 32, and the like. The self-line/pair-line demodulated output passes through the level converter 32 and enters the shift register 31, where the address, data, attributes, and parity are stored.
is temporarily accumulated. The shift clock is level converter 3
Output of 2 For details, PLL circuit 33 that operates with synchro ■
provides. The clock reproduced here is also input to the SV start trigger (frequency divider) 34, which operates the SV clock source 35, and the output of this clock source becomes the clock for the SV operation section 30, etc. (all input to the shift register 31). The parity (2) entered into the shift register 31 is subjected to a parity check, and if an error is detected, an SV response signal of the same format is used to request retransmission of the SV command signal.

The address ■ entered in the shift register 31 is compared with the address of the repeater in the address comparator 37, and if they do not match, the sending direction switch 36 sends out the SV command signal to its own line in the same format. If the address matches the own address, the address comparator 37 operates the attribute decoder 3.

The decoder 38 decodes the attribute ■ in the shift register 31, and if it is a command, opens the gate 39 and sends the data part ■ in the shift register 31 to the decoder 29.
This command decodes the command and causes the SV operation unit 30 to execute the command. This is the end, and the ISV command signal is not sent to either the own line or the paired line. This prevents the SV command signal from looping. If the attribute ■ in the shift register 31 is a response,
Since this has been looped back in the subsequent repeater, the direction bit of the attribute is inverted, the sending direction own line is changed to the enclosed line, and the sending is made. This allows the SV
The response signal also does not circulate through the loop.

When the SV operation section 30 executes the SV command signal, it sends out an SV response signal, and this is also done using the shift register 3I. That is, the response data is sent directly from the SV operation unit 30 to the shift register 31, and the response output is sent to the shift register 31 through the attribute decoding unit (encoding unit in this case) 38. A response signal is generated and sent out through the sending direction switch 36.

If the formats of the SV command signal and the SV response signal are the same, it becomes possible to process the signals in the SV execution section using a general-purpose processor.

In FIG. 3, a loopback (LB) detection section 40 is provided.

When looping back in the repeater, it is performed using the SV command signal, so the SV operation unit 30 of the repeater knows this and sends the LBON signal to the loopback detection unit 40. Upon receiving this, the detection unit 40 starts monitoring the attribute, and if it is a command, sends a signal to the transmission direction switch 36 to prohibit transmission (loopback) of the SV signal to the paired line. If it is a response, this prohibition is not performed and the SV signal is sent to the paired line.

〔Effect of the invention〕

As explained above, according to the present invention, even if loopback is performed, the SV command signal once executed will not be looped back and executed again, and SV signal propagation failure can be avoided. can.

[Brief explanation of drawings]

FIG. 1 is a principle diagram of the present invention; FIGS. 2 and 3 are block diagrams showing embodiments of the present invention 1 and 2; FIGS. 4 and 5 are block diagrams showing the already proposed device 1.2; FIG. 6 is a detailed diagram within the dashed line frame in FIG. 5, and FIG. 7 is an explanatory diagram of the optical transmission system. In Figure 1, IO is an upstream repeater, 2o is a downstream repeater, and 1
2a is an SV execution unit.

Claims (1)

[Claims] 1. A transmission line is constructed by inserting an optical direct amplification type repeater into an optical fiber, and the SV signal is propagated along with the main signal through the transmission line. In an SV signal propagation control method in an optical communication system that loops back with a repeater, the SV execution unit (12a) of the controlled repeater whose address of the SV command signal matches its own address transmits the SV command signal. An SV signal propagation control method characterized by stopping. 2. Insert an optical direct amplification type repeater into the optical fiber to configure a transmission line, propagate the SV signal along with the main signal on the transmission line, and loop back at the repeater following the controlled repeater during testing. In an SV signal propagation control method in an optical communication system, the SV execution unit (12a) of the loopback repeater:
Check the attributes of the SV signal and confirm that the signal is S
An SV signal propagation control method characterized by stopping transmission if it is a V command signal.