JPS5871738A - Monitoring system for light relaying transmission line - Google Patents

Abstract

PURPOSE:To transmit the monitor state of a regenerative repeater to an end office, by providing a means into a regenerative repeater to detect a pulse train that is modulated by a specific frequency for monitor which is allotted to own. CONSTITUTION:An end office 3 is connected to another end office (not shown in the diagram) via ascending and descending optical fibers 1 and 2 and numbers of regenerative repeater 4. When monitoring the repeater 4, the offices 3 modulates the monitor frequency signals supplied from an oscillator 51 by means of a pulse train sent from a pulse generator 52 in a signal transmitter 5 and then feeds the signals to the fiber 1. The signals regenerated by the regenerative repeater 4 are applied to a monitor device 43, and a detector 301 applies an output to a comparator 302 if the monitor frequecy is alloted to the comparator 302 itself. The comparator 302 controls gates 117, 118 and 123 in response to the result of comparison with a reference voltage generator 303. The signal of an oscillator 121 which has oscillations with the control voltage to a photoelectric converter 101 is modulated to a pulse and then fed to the signal receiver of the office 3 via a coupler 209 of a dvice 42 at the descending side. Receiving this signal, a frequency meter 63 and an error factor measuring device 7 indicate the state of the repeater 4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a monitoring system for digital communication systems using optical fiber communication lines. In particular, the present invention relates to a monitoring system suitable for a submarine optical relay transmission system in which a large number of digital regenerative repeaters are inserted.

Monitoring methods for digital relay transmission systems using optical fiber communication lines can be broadly divided into those that monitor while the main communication signal is being transmitted, and those that perform monitoring by stopping the main communication signal and sending a special monitoring signal. There is something to do.

The present invention belongs to the latter category, and is intended to further increase the variety and sophistication of information obtained through monitoring.

When optical fiber communication lines and regenerative repeaters are installed on land, if a failure occurs in the relay transmission line, operations such as manually turning back the transmission line are performed to investigate the location and cause of the failure. be able to. However, in submarine communication systems, it is almost impossible to directly modify the transmission path in this way, so it is necessary to loop back and measure signals by remote control from the terminal station. As a system for this purpose, the applicant of the present patent application has filed document (1) % Ichihashi Application No. 56-152540 ``Monitoring System for Digital Relay Transmission Line''. Literature (2) as content corresponding to this invention
Denbashi, Koyama et al. “Experimental study of submarine optical repeater monitoring method”
1981 IEICE General National Conference No. 223
0 was disclosed. In this technique, by remote control from a terminal station, a transmission signal is returned to a transmission line in the opposite direction at a specific repeater, and the signal is received at the terminal station to perform measurements such as error rate measurement.

The present invention further advances this, and in addition to measuring errors, various voltages generated within the repeater, such as the control level of the receiving circuit AGO, or the bias voltage of the photoelectric converter or electro-optical converter, etc. The present invention provides a system that allows information to be transmitted to a terminal station by remote control.

In addition, as a known technique related to the present invention, there is a document (3) "Design of the PCM-400M Fault Detection System" published by Nippon Telegraph and Telephone Public Corporation Telecommunications Research Institute, No. 25 of the Research Kangetsuka Report.
Volume No. 1 (1976) pp 1! i3-147 Literature (4) Kishita, Yojima et al., ``Study of fault detection method for PCM relay transmission line,'' 1978 Institute of Electronics and Communication Engineers General National Conference No. 1727.

That is, an object of the present invention is to provide a monitoring system that can transmit various types of DC voltage information generated in a repeater to a terminal station by remote control from the terminal station. Moreover, in addition to the above-mentioned object, the second invention of the present application aims to provide a monitoring system that can return a transmitted signal by a repeater by remote control if necessary.

The present invention modulates and transmits a pulse train signal at the communication speed of a relay transmission path from a terminal station at a specific frequency assigned to each repeater, and each repeater has a frequency assigned to its own repeater. comprising a circuit for identifying a specific frequency of the octopus, and means for generating a monitoring signal of a frequency corresponding to the DC voltage inside the repeater;
When this specific frequency is identified, it is configured to send this monitoring signal to the transmission path in the opposite direction. The terminal station can detect the frequency of this monitoring signal and know the DC voltage inside the repeater.

The second point of the present invention is that in the above configuration, by changing the mark rate of the pulse train signal sent from the terminal station, the level of the signal of the specific frequency is changed, and the repeater can adjust the level according to the magnitude of this level. , and is configured to distinguish whether to send the monitoring signal to the transmission line in the opposite direction or to loop back and send out the signal that has been transmitted once.

In either case, it is preferable that the pulse train signal is precoated and sent out at the terminal station, and decoded when detected at each repeater. As a result, the mark rate on the transmission path becomes close to 1/2, making it possible to avoid the adverse effects caused by uneven mark rates.

Next, a detailed explanation will be given using embodiment drawings.

FIG. 1 is a block diagram of a method according to an embodiment of the present invention. 1
is an optical fiber communication line for the upper 9, 2 is an optical fiber communication line for the lower, and optical fiber communication is carried out from the transmission terminal 31 of the terminal station 3!
! A light pulse train signal is sent to 1. This is transmitted to the right in Figure 1, passes through regenerative repeater 4, is further transmitted to the right, and passes through many other regenerative repeaters (not shown) and optical fiber communication lines. is input to the other party's terminal station.

On the other hand, the multiplication pulse train signal transmitted from the other party's terminal station is transmitted to the left in the diagram, appears at the optical fiber communication 92 at the bottom right of Figure 1, and is further transmitted to the left via the regenerative repeater 4. and enters the receiving terminal 32 of the terminal station 3 from the optical fiber communication 1Ii12.

In FIG. 1, the transmitting device 5 is connected to the input terminal 33 of the terminal station 3 at the ninth point when the adjustment according to the present invention is performed. Similarly, the receiving device 6 is connected to the output terminal 34. An error rate measuring device 7 is connected between the transmitting device 5 and the receiving device 6.

During normal communication, this input terminal 33
K is given a transmission input pulse train signal (electrical signal),
A received output pulse train signal (electrical signal) is obtained at the output terminal 34. When monitoring according to the present invention, KFi devices 5 and 6 are connected in place of these transmitting and receiving pulse train signals.

The terminal station 3 includes a device that amplifies the electrical signal at the input terminal 33, converts it into an optical signal, and transmits it to the transmission terminal 31, and a device that converts the optical signal received at the reception terminal 32 into an electrical signal and regenerates and amplifies it. A device for sending this to the output terminal 34 and other devices are included, but these devices are well known and are not directly related to the present invention, so detailed configurations will be omitted.

In Figure 1, the regenerative repeater 4 is connected to the optical fiber communication lines 1 and 2.
Although a large number of them are inserted at predetermined intervals, only one of them is shown here and its configuration will be explained in detail. However, in FIG. 1, only the parts directly related to the present invention are shown in detail, and circuits for supplying power to these devices, for example, are omitted.

Of the regenerative repeater 40 circuits shown in FIG. 1, the part surrounded by a broken line 41 is the upstream side equipment, the part surrounded by the broken line 42 is the lower side equipment, and the part surrounded by the broken line 43 is the upstream and downstream equipment. This is a monitoring device connected between

To explain the upper side device 41, it is optical fiber communication! The optical signal input from 11 is converted into an electrical signal by a photoelectric converter 101, and then passed through amplifiers 102 and 103.
It is input to an equalizer 104 and a timing circuit 105. The output of the equalizer 104 is discriminated and reproduced by the discriminator 106 together with the output of the timing circuit 105. This output signal is passed through a coupler 109, a converter 110 that converts the NR2 (non-return-to-zero) signal into an RZ (return-to-zero) signal, and then to the driver 111.
K is given. The output of this driver 111 is the electro-optical converter 1
12 to convert the signal into an optical pulse train signal and send it to the optical fiber communication line 1 of the next section.

The output signal of the equalizer 104 is branched and subjected to automatic gain control (A
GC) circuit 107, and this control output is applied to the amplifier 1
03 and voltage converter 108.

The output voltage of this voltage converter 108 is the same as that of the photoelectric converter 101.
Give the operating bias voltage to.

Here, the feature of the present invention is that this voltage converter 1
The MuGC control voltage taken out from the gate circuit 122.
123 to one input of an exclusive OR circuit 124, where it is modulated with the output of the discriminator 106 that has passed through the gate circuit 117. The output of this exclusive OR circuit 124 is given to the combiner 209 of the downstream device 42 on the opposite side, and is combined with the downstream signal.

Regarding the lower side device 42, the above-mentioned upper side device 41
The first digit of the code of each block is 2.
, the second and third digits are shown in bold numbers, so they can be understood in the same way.

A further feature of the present invention is the monitoring device 43. The RZ multiplied signal obtained at the output of the converter 110 is applied to a T-type 7 lip-flop 114, the output of which is input to the detector 301. This detector 301 is configured to pass an input signal through a narrow band P-wave device and detect and rectify the output.The passing frequency of the band P-wave device is the above-described specific frequency, and each regenerative relay A different frequency is assigned to each device.

The output of this detector 301 is given to a comparator 302 and compared with a reference voltage generated by a reference voltage generator 303.

This comparator 302 has two outputs 304 and 305. That is, the reference voltage generator 303 generates two reference voltages of 81 and ms when KBl<Bs2, and when the output Kx of the detector 301 is lx(ms2), there is no output signal at the outputs 304 and 305, [8, (K engineering (when 182, output signal is sent only to output 304, "x
>KS2, output signals are sent to outputs 304 and 305. That is, depending on the output level of the detector 301, either the gate circuits 117 and 118 are opened or the gate circuits 123 and 123 are opened.
Also configured to control opening.

In FIG. 1, the transmitting device 5 generates a pulse train signal at the transmission speed of this relay transmission path, and the mark rate of the pulse train signal is variably set from about 1/8 to about 174 in this example.
An N-bang generator 51 is provided.

It also includes an oscillator 52 that selects and generates a specific frequency assigned to each regenerative repeater.

The outputs of the PM bang generator 51 and oscillator 52 are applied to two inputs of an exclusive OR circuit 53, and the output thereof is applied to a precoat circuit 54. This precoat circuit 54 includes a circuit that calculates the exclusive OR of an input pulse train and a signal obtained by delaying this input pulse train by one bit. Without losing information, the output pulse train signal is adjusted so that the mark rate is close to 1/2.

More precisely, the mark of the PM bang generator 51.

When the ratio is 1/8 and '/4, the mark ratio after precoating is /fi7/32.3/8, respectively. As is known, this precoated signal is passed through a T-type flip-flop (
In this example, circuit 114) can be dynamically coded, and its output Kid pre-coated signal is obtained.

The output of this precoat circuit 54 is converted to R by a converter 55.
The signal is converted into a Z-fold signal and applied to the input terminal 33 of the terminal station 3. Moreover, the output of the precoat circuit 54 is i14! The reference measurement device 7 is provided with a reference input.

In FIG. 1, the receiving device 6 converts the signal applied to the output terminal 34 of the terminal station 3 into an MRZ signal using the converter 61, and extracts this output via the low-band p-wave converter 62, thereby transmitting the above-mentioned signal. The frequency of the monitoring signal (output of the voltage controlled oscillator 121) is output and the frequency meter 63 reads this frequency. Also,
The output #'ig4 of the converter 61 is input to the rate measuring device 7.

Next, the operation of the device configured as described above will be explained.

First, an optical signal input to the frame and photoelectric converter 101 when a normal communication signal is being transmitted is converted into an electrical signal,
The signal is amplified and regenerated and sent out from the electro-optical converter 112. At this time, there is no signal at the output of the detector 301, both the gate circuits 117 and 12311t are inactive, and the exclusive OR circuit 124 has no input.

Next, the transmitting device 5 and the receiving device 6 are connected to the terminals 33 and 33 respectively.
A case will be described in which the monitoring operation is performed by being connected to 34 and 34. Figure 2 is a waveform diagram to explain the operation at this time ~ Figure 2 (A) to (S) are the points (A) to (S) shown with X marks in Figure 1, respectively. FIG. In FIG. 2, the shaded area indicates the presence of a high-speed pulse train signal (for example, 400 ub/s) equal to the transmission speed of the relay transmission line, and the broken line represents the average level of the pulse train.

Now, a pulse train signal (a) with a mark rate of 178 is sent out from the PN bang generator 51. - A signal of a specific frequency (for example, 200 kHz) assigned to the regenerative repeater that is currently being located is sent from the perfect shaker 52. When this is modulated by the exclusive OR circuit 53, a pulse train signal (c) is coarsely and finely modulated at this specific frequency.
get. This is precoated by a precoat circuit 54 and becomes a pulse train signal.

This signal is converted into an RZ signal and further converted into an optical signal, which is transmitted through optical fiber communication ill, reaches the regenerator 4, and is amplified and regenerated. The signal shown is obtained. This is converted into a FiRZ signal and input to the T-type 7 lip-flop 114. The precoat applied by the precoat circuit 54 is decoded to the output of this T-type 7 lip-flop 114, and the precoat applied by the precoat circuit 54 is decoded, and
The signal shown in e) appears. This is equivalent to Figure 2 (c).

This signal is detected by the detector 301, and if this is the specific frequency assigned to this regenerative repeater, the detected output of this specific frequency is obtained as its output. When the output level Kz/fi of this detection output (to) and the mark rate of the output pulse train of the PN pattern generator 51 are m, Ex = k l 1-2 + n l where k
It is known that Fi is a constant. This is explained in detail in the above-mentioned document (4), so the explanation will be omitted here.

Now, since the mark rate m is #117B, the detector 30
The output level of 1 is quite large, Kx) I? It is in state 2. Therefore, as mentioned above, comparator 302
Output signals appear at outputs 304 and 305, and gate circuits 123.118.117 become active.

As a result, the monitoring signal (G) (for example, 10kHz) that is the output of the stain pressure control oscillator 121 is added with a timing signal to the gate circuit 122, and the exclusive OR circuit 12
K modulation is applied to the signal that has passed through the gate circuit 117. The output signal is inserted into the down line from the down line coupler 209 on the opposite side and transmitted as a pulse train signal.

This signal appears at the terminal 34 and is applied to the receiving device 6,
The fundamental wave component (S) of the monitoring signal (G) is extracted by converting it into an NRZ code and passing it through a low-band p-wave converter 62. This can be measured by the frequency meter 63, and the value of the DC voltage applied to the voltage controlled oscillator 121 can be found.◇This DC voltage is a voltage proportional to the control voltage in this example. Therefore, the output level of the equal stopper 104 in the receiving circuit of the regenerative repeater 4 can be known.

Moreover, since any desired regenerative repeater 4 can be selected by selecting the frequency of the oscillator 52 of the transmitter 5, the reception level of any desired regenerative repeater can be measured by remote control. .

Next, when the PN bang generator 51 of the transmitting device 5 is turned off, the output level 1lix of the detector 301 of the regenerative repeater 4 becomes smaller and becomes Fj8,<l<E82. An output signal is sent only to the output 304 of the comparator 302, and the gate circuit 123 becomes inactive. Therefore, the output signal of the discriminator 106 passes through the gate circuit 117, further passes through the exclusive OR circuit 124, and is often returned from the coupler 209 to the lower line.

In this state, the reference input of the error measuring device 7 is given the transmitted pulse train, and the measurement input is given the received pulse train, so that the error rate can be measured correctly. In this case as well, the regenerative repeater can be selected by changing the sending frequency of the oscillator 52 of transmitter #5, so the signal return point can be selected.

The above explanation is about the operation when sending a control signal on the upstream side and obtaining a monitoring result on the downstream side, but since the reverse case is exactly the same, the explanation will not be repeated.

In this way, it is possible to locate the location of the failure in the relay transmission line, and also to know in considerable detail the cause of the failure.

Note that the DC voltage applied to the voltage controlled oscillator 121 is not limited to the above example, and other necessary information can be provided.

The relationship between the output levels of signals of specific frequencies is not limited to the above example, and can be determined in various ways.

Although the above example shows modulation using an exclusive OR circuit, the present invention can also be practiced with other modulations.

Glycoding and decoding are not necessarily necessary depending on the line quality.As described above, according to the present invention, various DC voltage information generated in each repeater is measured at the terminal station by remote control. be able to.

Therefore, the characteristics of the repeater can be known to a considerable extent without directly accessing the repeater.

Furthermore, according to the second aspect of the present invention, in addition to the above-mentioned effects, the transmitted signal can be looped back at any repeater by remote control, which is extremely effective in locating the location of a fault and searching for its cause.

The system of the present invention is highly effective when implemented in submarine communication systems where direct access to repeaters is difficult.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention. FIG. 2 is a waveform diagram for explaining the operation. 1.2...Optical fiber communication line, 3...Terminal station, 4...
- Regenerative repeater, 5... transmitting device, 6... receiving device,
7...-Shi rate measuring device. Child 2 Illustration procedure amendment document 3rd year of 1982? Hinase, 5° Fraud Office Chief Island 1) Haru Judono 1.1R+ Display 1982 Patent Application No. 171923-2, Title of Invention Monitoring System for Optical Relay Transmission Line 3 Person Who Makes Amendment Relationship with Case 41 Patent Applicant Representative Hisashi Shindo 4, Agent 6 Detailed explanation of the invention increased by amendment Figure 1 will be replaced as shown in the attached drawing. The correction points are at the branch points where the signal line 304 from the circuit 302 goes to the circuits 117.118 and 217.218.
This is the part with the black circle added. Other parts remain unchanged. 9 Attached document drawing (Figure 1) 1 copy

Claims (2)

[Claims] (1) Two terminal stations, two optical fiber communication lines in the vertical direction installed between these terminal stations, and nine or more digital regenerative repeaters inserted into each of the optical fiber communication lines at predetermined intervals. In a method for monitoring an optical relay transmission line including the above, a pulse train signal having the transmission speed of the relay transmission line is modulated at a position of at least one of the two terminal stations at a specific frequency assigned to each regenerative repeater. and a means for transmitting the signal to the signal input terminal of the terminal station;
Means for generating a monitoring signal of a frequency corresponding to the monitored DC voltage in the regenerative repeater, and optical fiber communication from the one terminal station to the one terminal station on the relay transmission line! ! means for extracting a pulse train transmitted to the regenerative repeater and modulating the pulse train with the monitoring signal; means for detecting a signal of the specific frequency assigned to the regenerative repeater from the pulse train transmitted to the relay transmission line; means for transmitting the output pulse train of the means modulated by the monitoring signal from the regenerative repeater to the one terminal station via the other optical fiber communication line when the means has a detection/output output; A monitoring system for an optical relay transmission line, characterized in that the one terminal station is provided with means for detecting the frequency of the monitoring signal from the pulse train received from the relay transmission line. (2) Two terminal stations, two optical fiber communication lines in the vertical direction provided between the terminal stations, and a plurality of digital regenerative repeaters inserted into each of the optical fiber communication lines at appropriate intervals. In a system for monitoring an optical repeater transmission line including: a pulse train signal having a transmission speed of the above-mentioned repeater transmission line is assigned to each regenerative repeater at the position of at least one of the above two terminal stations at a specific frequency; a means for modulating the signal and sending it to the signal input terminal of the terminal station; and a means for variably setting the mark rate of the pulse train signal; means for generating a monitoring signal of a corresponding frequency;
A means for extracting a pulse train transmitted from the one terminal station to one optical fiber communication line on the relay transmission line and modulating this pulse train with the monitoring signal, and reproducing and relaying the pulse train from the pulse train transmitted to the relay transmission line. means for detecting a signal of the specific frequency assigned to the device; means for determining whether the amplitude level of the detection output of the means exceeds a predetermined level; and the detection means has a detection output and the determination is made as described above. When the amplitude level is on one side with respect to the predetermined level, the output pulse train of the means for modulating with the monitoring signal is directed from the regenerative repeater to the one terminal station and the other source fiber communication. a means of transmitting over a line;
The detecting means has a detection output, and the determining means transmits a pulse train from the one terminal station to the relay transmission line when the amplitude level is on the other side with respect to the predetermined level. and means for returning the signal to the one terminal station via the other optical fiber communication line, and further transmitting the monitoring signal from the pulse train received from the relay transmission line to the one terminal station position. means for detecting the frequency of
1. A method for monitoring an optical relay transmission line, comprising: means for measuring the rate of transmission.