JPH07162365A - Optical subscriber system monitoring system - Google Patents

Abstract

PURPOSE:To quickly correspond to fault generation by always returning a bidirectional optical subscriber transmission line in an optical area. CONSTITUTION:This optical subscriber system monitoring system is provided with a down transmission signal processing circuit 10 for executing the signal processing and electro-optical (E/O) conversion of a down transmission signal (a), an optical transmitting circuit 11, an optical receiving circuit 12 for executing the O/E conversion and signal processing of an optical up transmission signal (d), an up receiving signal processing circuit 13, a data comparator circuit 14 for monitoring optical fibers 2-1, 2-2, a level comparing/juding circuit 15, an up receiving signal detecting circuit 16, and a fault judging circuit 17. The system is also provided with an optical branching circuit 30 for branching an optical down transmission signal (c), an optical receiving circuit 32 for executing the O/E conversion and signal processing of an optical down receiving signal (k), a down receiving signal processing circuit 33, an up transmission signal processing circuit 34 for executing the signal processing and E/O conversion of an up transmission signal (p), an optical transmitting circuit 35, and a photocouping circuit 36 for coupling an optical up transmission signal (r) with an optical return signal (m).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical subscriber system monitoring method, and more particularly to an optical subscriber system monitoring method for performing a loopback test in the optical region.

[0002]

2. Description of the Related Art Referring to FIG. 3, a first conventional optical subscriber system monitoring method is to convert a downstream input electric signal A from an electric signal to an optical signal to convert a downstream optical signal B to an optical fiber signal. Electric / optical converter 10 for outputting to transmission line 20-1
1 and an optical / electrical converter 102 that converts an upstream optical signal c from the optical fiber signal transmission line 20-2 from an optical signal to an electrical signal and outputs an upstream output electrical signal d. The first unit 10 for determining data matching / mismatch between the input electrical signal A and the upstream output electrical signal D, and the first unit 10 through the optical fiber signal transmission line 20-1.
The downstream optical signal B input from the electro-optical converter 101 of the unit is normally connected in the downstream direction to be output as the downstream optical signal output, and is switched and connected in the folding direction at the time of the folding test, and the folded optical signal co As optical fiber cable 3
Optical connector 301 for outputting to 02, and optical connector 301
Optical / electrical converter 303 for converting the downstream optical signal F from the optical signal into an electrical signal and outputting it as a downstream output electrical signal K
And an electrical / optical converter 304 for converting the upstream input electrical signal 7 from an electrical signal to an optical signal and outputting an upstream optical signal, and an upstream optical signal from the electrical / optical converter 304 in the normal direction in the upstream direction. Connected to the optical fiber signal transmission line 20-2 as an upstream signal C, and is switched and connected in the return direction at the time of the return test, and the return optical signal C input from the optical connector 301 through the optical fiber cable 302 is used as the upstream optical signal. And a second unit 30 having an optical connector 305 for outputting to the optical fiber signal transmission line 20-2.

With this configuration, during the system turn-back test, the optical connector 301 and the optical connector 305 are normally connected to the optical / electrical converter 303 and the electrical / optical converter 304 from the optical fiber cable 302. Simultaneously, the transmission path through which the downstream input electric signal A input to the first unit 10 is output from the second unit 30 as the downstream output electrical signal is cut off at the optical connector 301 during the loopback test. The upstream input electrical signal input to the second unit 30 is the first
The transmission path output from the unit 10 as the upstream output electric signal D is blocked at the optical connector 305.

In this folded state, in the first unit 10, a downlink input electric signal a input to the electric / optical converter 101 and a downlink optical signal a obtained by electric / optical conversion of the downlink input electric signal a are provided. The presence / absence and correctness of the data of the upstream output electric signal D which is folded back in the upstream direction by the optical connector 301, the optical fiber cable 302, and the optical connector 305 and is optically / electrically converted by the optical / electrical converter 102 and output is determined. If the data is “present” and both data are “match”, it is determined that the optical fiber signal transmission line 20-1 and the optical fiber signal transmission line 20-2 are normal, and the data is “absent” and “erroneous”. If it is ", it is determined that one or both of the optical fiber signal transmission line 20-1 and the optical fiber transmission line 20-2 is abnormal.

Next, referring to FIG. 4, the optical subscriber system monitoring method which is the above-mentioned second conventional technique is as follows. In the event of an abnormality in which the power-off detection signal is input as the signal output, the line supervisory signal generation that outputs, for example, the line supervisory signal H whose data is all "1" signal as the electrical downlink signal S Section 401 and the electrical / optical conversion section 50 for converting the electrical downlink signal from the line supervisory signal generation section 401 into an optical signal and outputting the optical downlink signal to the downlink optical subscriber line 50-1.
-1, an optical / electrical converter 403 for converting the optical upstream signal input from the upstream optical subscriber line 50-2 from an optical signal to an electrical signal and outputting an electrical upstream signal S, and an optical / electrical converter. The presence or absence of a power cutoff signal is detected from the electrical upstream signal S0 input from 403. When the power cutoff signal is "present", a power cutoff detection signal is output to supply to the line supervisory signal generation unit 401 and a power cutoff is detected. Power-off signal detector 404 that outputs a signal
And the presence / absence of a line supervisory signal from the electrical upstream signal S0 input from the optical / electrical conversion unit 403 when the power shutdown detection signal Ts is input from the power shutdown signal detection unit 404 and, for example, data of all "1" signals. Is detected and the line supervisory signal is "absent" or the data of all "1" signals is "erroneous", the line supervisory signal detector 405 which outputs a line fault alarm signal TE and the optical / electrical converter 403. An internal disconnection detection unit 406 that detects the presence or absence of the original electrical upstream signal transmitted from the electrical upstream signal S0 input to the host device and outputs a fault alarm signal when the electrical upstream signal is "absent" The optical terminal device 1 and the optical downlink signal from the electrical / optical conversion unit 402 of the intra-station optical terminal device 1 that is input through the optical subscriber line 50-1 are normally optical when the power cut detection signal is not input. Switch The contact point X of the optical switch is connected to the contact point Y of the optical switch, and when the power failure detection signal is input, the contact point X of the optical switch is connected to the contact point Z and folded back. An optical return section 601 for switching the optical signal D to be output to the optical fiber cable 602 and outputting the return optical signal D to the upstream optical subscriber line 50-2 as an optical upstream signal source, and an optical downlink from the optical return section 60. An optical / electrical conversion unit 603 that converts an optical signal from an optical signal into an electrical signal and outputs an electrical downstream signal d.
When the power supply is “absent”, a power failure detection signal is output to supply to the optical folding section 601 and a power failure is detected. A power failure detection unit 605 that outputs a signal NE, and a power failure signal generator 606 that outputs a power failure signal C when the power failure detection signal 605 is input from the power failure detection unit 605 and couples it to the electrical upstream signal HI. And an optical / electrical conversion unit 607 that converts the electrical upstream signal H and the power-off signal C from the power source signal generation unit 606 from an electrical signal to an optical signal, outputs an optical upstream signal F, and supplies it to the optical folding unit 601. And a home optical terminal device 60 included therein.

With this configuration, in the system turn-back test, while the in-home optical termination device 60 is in the power stage state, the in-home optical termination device 60 sends a power-off signal c to inform that fact.
From the optical fiber to the intra-station optical terminator 40 through the optical subscriber line 50-2 as an upstream optical signal, and at the same time, the power interruption detection signal is supplied to the optical loopback section in the own apparatus to operate the optical switch X.
The connection between the contact and the Z contact is switched to set the folded state in the light region.

In the intra-station optical terminator 40, the home optical terminator 6
When a power-off signal c is sent from 0, the power-off signal detector 404 detects it and supplies it as a power-off detection signal to the line supervisory signal generator 1 and also disconnects the power to the line supervisory signal detector 405. It is supplied as a detection signal. The line supervisory signal generator 401 outputs the line supervisory signal of all "1" as an electric downlink signal S, instead of the electric downlink signal S, when the power shutoff signal detector 401 supplies the power shutoff detection signal TA. . The line supervisory signal output from the line supervisory signal generation unit 401 as the electric downlink signal S is electrically / optically converted by the electric / optical conversion unit 402, and is transmitted as an optical downlink signal S through the optical subscriber line 50-1 to the optical loopback unit. 601
And is input to the in-station optical terminator 40 again as an optical upstream signal signal via the optical subscriber line 50-2.
The line supervisory signal as the optical upstream signal input to the intra-station optical terminator 40 is re-opticalized by the optical / electrical conversion unit 403.
The signal is electrically converted and is input to the line supervisory signal detection unit 405 as an electric upstream signal S0. The line supervisory signal generation unit 405 determines whether or not there is data, for example, all “1” signal of the line supervisory signal input as the electrical upstream signal S0 when the power shutoff signal detector 404 inputs the power shutoff detection signal Ts. Is detected and the data is “present” and “positive”, the downstream optical subscriber line 50-1 and the upstream optical subscriber line 50-2 are detected.
Are both normal, and when the data is “present” and “erroneous” or when the data is “absent”, the downstream optical subscriber line 50-1 and the upstream optical subscriber line 5 are
It is determined that either or both of 0-2 are abnormal, and the line fault alarm signal TE is output. The input disconnection detection unit 406 is performed when the loopback test by the line monitoring signal is normal and the power supply disconnection signal detection unit 404 does not detect the power supply disconnection signal, that is, when the power termination signal C is not output from the home terminating device 60. When the output of the electric upstream signal is detected and the fault alarm signal is output, the optical / electrical conversion unit 607
It is determined that an abnormality has occurred in another function of the home track apparatus 60 except for.

Next, referring to FIG. 5, the optical subscriber system monitoring method, which is the third conventional technique described above, normally connects the contact X to the contact Y to connect the downstream transmission signal to the downstream transmission signal. An electric switch 701 which outputs the return test transmission signal e as a downward transmission signal by switching and connecting the contact X to the contact Z during the return test.
An optical transmitter 702 for converting the downlink transmission signal from the electric switch 701 into an optical signal having a wavelength λ ₁ from the electric signal and outputting an optical downlink transmission signal M, and a wavelength λ from the optical transmitter 702.
The optical downlink transmission signal M of ₁ is demultiplexed and output as the optical downlink transmission signal to the optical fiber cable 80-1 of the bidirectional transmission path, and the wavelength of the light input from the optical fiber cable 80-1 is λ ₂ . An optical multiplexer / demultiplexer 703 having a directivity for demultiplexing the transmission signal pair into the own device and outputting it as an optical upstream transmission signal, and a wavelength λ ₂ from the optical multiplexer / demultiplexer 703.
The optical receiver 704 that converts the optical upstream transmission signal e from the optical signal to the electrical signal and outputs the upstream reception signal M, and the downstream transmission signal LA from the electrical signal to the optical signal with the wavelength λ ₂ An optical transmitter 705 that outputs a transmission signal and an optical transmitter 7
The optical downlink transmission signal L having the wavelength λ ₂ from 05 is demultiplexed and output as an optical downlink transmission signal to the optical fiber cable 80-2 of the bidirectional transmission path and the optical fiber cable 80-
2. The optical multiplexer / demultiplexer 706 and the optical multiplexer / demultiplexer 70 having a directivity for demultiplexing the optical upstream transmission signal PO having a wavelength of λ ₁ input from the device 2 and taking it into the own device and outputting it as an optical upstream transmission signal RE.
An optical receiver 70 for converting the optical upstream transmission signal of wavelength λ ₁ from the optical signal 6 into an electrical signal and outputting the upstream reception signal b
7. Normally, the contact X is connected to the contact Y to output the upstream reception signal B as the upstream reception signal W, and the contact X is switched and connected to the contact Z during the return test, and the upstream reception signal B is returned to the test reception signal. Switch 7 to output as
08 and a loopback tester 709 which outputs a loopback test transmission signal E and supplies it to the electric switch 701 and receives a loopback test reception signal signal from the electric switch 708 to judge the loopback test result.
0; optical demultiplexing signal of wavelength λ ₁ from the optical multiplexer / demultiplexer 703 of the terminal device 70, which is input through the optical fiber cable 80-1, is demultiplexed and taken into the own device, and optical downstream reception of wavelength λ ₁ is received. The optical upstream transmission signal D having a wavelength of λ ₂ from within the device itself is demultiplexed and output to the optical fiber cable 80-1 as an optical upstream transmission signal P of the wavelength λ ₂ of the terminal device 70. The optical multiplexer / demultiplexer 901 to be sent to the optical multiplexer / demultiplexer 703, and the contact X is normally connected to the contact Y to output the optical downstream reception signal signal from the optical multiplexer / demultiplexer 901 as the optical downstream reception signal pi and return it. At the time of the test, the contact X is switched to the contact Z to switch the wavelength λ ₁ from the optical multiplexer / demultiplexer 901.
The optical switch 903 that outputs the optical downlink reception signal P as the optical return test reception signal, and the optical reception that converts the optical downlink reception signal P from the optical switch 903 from an optical signal to an electrical signal and outputs the downlink reception signal P. 904, an optical transmitter 905 for converting the upstream transmission signal from an electric signal to an optical signal, outputting an optical upstream transmission signal GI having a wavelength of λ ₂ and supplying the optical upstream / outgoing signal 901 to the optical multiplexer / demultiplexer 901, and the optical fiber cable 80. -2 from the optical multiplexer / demultiplexer 706 of the terminal device 70 input through
The optical downstream transmission signal of ₂ is demultiplexed into the own device and output as an optical downstream reception signal of wavelength λ ₂ and the optical upstream transmission signal of wavelength λ ₁ from within the own device is demultiplexed and output. An optical multiplexer / demultiplexer 906 that outputs to the fiber cable 80-2 and outputs to the optical multiplexer / demultiplexer 706 of the terminal device 70 as an optical upstream transmission signal of wavelength λ ₁ , and a wavelength λ from the optical multiplexer / demultiplexer 906.
_The optical receiver 907 that converts the optical downlink reception signal G2 of FIG. ₂ from an optical signal to an electric signal and outputs it as a downlink reception signal, and the uplink transmission signal G0 from an electric signal to an optical signal and has a wavelength of λ ₁
The optical transmitter 908 which outputs the optical upstream transmission signal The and the contact X at the normal time are connected to the contact Y, and the optical upstream transmission signal The of the wavelength λ ₁ from the optical transmitter 908 is output as the optical upstream transmission signals. The optical switch 903 is supplied to the optical multiplexer / demultiplexer 906 and the contact X is switched and connected to the contact Z during the return test.
A repeater 90 having an optical switch 909 for outputting the optical loopback test reception signal j having the wavelength λ ₁ input from the optical fiber cable 902 for loopback as optical upstream transmission signals and supplying it to the optical multiplexer / demultiplexer 906; Composed of.

With this configuration, normally, the optical fiber cable 80-1 and the optical fiber cable 8 are exchanged between the upper device and the lower device via the terminal device 70 and the relay device 90.
Each bidirectional communication is performed by two bidirectional transmission lines of 0-2, but during the loopback test of the system, communication between the upper device and the lower device is performed from the relay device 90 through the optical fiber cable 80-1. The communication is limited to the upstream communication with the wavelength λ ₂ toward the station device 70 and the downstream communication with the wavelength λ ₁ toward the relay device 90 from the terminal device 70 through the optical fiber cable 80-2. Terminal device 7 with wavelength λ ₁ through fiber 80-1
Downlink communication from 0 to the relay device 90 and upstream communication from the relay device 90 to the terminal device 70 through the optical fiber 80-2 are used for the loopback test of the system. That is, two systems of bidirectional transmission lines are prepared in order to enable the loopback test in the optical region of the system using the bidirectional transmission lines, and accordingly, downlink signal transmission / reception means and uplink signal transmission / reception means are provided. Two receiving means are required.

Next, the operation during the folding back test will be described. The electric switches 701 and 708 of the terminal device 70 and the optical switches 903 and 909 of the relay device 90 are controlled to be switched from the connection between the contact X and the contact Y to the connection between the contact X and the contact Z in advance before the return test. Set to state. In this folded state, the folded back tester 70
The loopback test transmission signal e output from the optical switch 7 is output as the downlink transmission signal 2 from the electric switch 701 and is transmitted to the optical transmitter 7
In 02, the electric signal is converted into an optical signal of wavelength λ ₁ and output as an optical downlink transmission signal mi. Optical transmitter 702
The return test transmission signal as the optical downstream transmission signal M from the optical fiber cable 80 is transmitted to the optical multiplexer / demultiplexer 703.
It is demultiplexed to -1 and is output to the optical multiplexer / demultiplexer 901 of the repeater 90 as an optical downlink transmission signal of wavelength λ ₁ . The return test transmission signal as the optical downlink transmission signal input to the optical multiplexer / demultiplexer 901 of the repeater 90 is the optical multiplexer / demultiplexer 901.
Is demultiplexed and output as an optical downstream reception signal λ _{1 and} is output to the optical fiber cable 902 for return as an optical return test reception signal j through the contact points X and Z of the optical switch 903. The optical return function reception signal D input from the optical switch 903 through the optical fiber cable 902 is returned in the upstream direction through the contact Z and the contact X in the optical switch 909 and is output as the optical upstream transmission signal of the wavelength λ ₁ and the optical multiplexer / demultiplexer. 906. The optical multiplexer / demultiplexer 906 demultiplexes the optical return test reception signal as the optical upstream transmission signals returned by the optical switch 909, outputs the demultiplexed signal to the optical fiber cable 80-2, and outputs the wavelength λ ₁
The optical multiplexer / demultiplexer 7 of the terminal device 70 as the optical upstream transmission signal
Return to 06. The optical return test reception signal of wavelength λ ₁ as the optical upstream transmission signal returned to the optical multiplexer / demultiplexer 706 of the terminal device 70 is demultiplexed by the optical demultiplexer 706 and output as the optical upstream reception signal. 707 is supplied. The optical loopback test reception signal as an optical upstream reception signal signal from the optical demultiplexer 706 input to the optical reception signal 707 is converted from an optical signal to an electrical signal and output as the upstream reception signal b, and the contact point of the electrical switch 708. Loop-back tester 7 as a loop-back test reception signal signal through X and contact Z
09 are supplied. The loopback tester 709 detects the presence / absence of a loopback test reception signal that is looped back and input within a predetermined time after outputting the loopback test transmission signal e, and the loopback test reception signal is returned and input within a predetermined time. When it is determined that the return data is compared with the data of the return test transmission signal e at the time of transmission output, the correctness is determined. When the determination result is "correct", the fiber cable 80-1 and the optical fiber cable 80-2 Both are judged to be normal. If the loopback test reception signal is not returned within the predetermined time, the optical fiber cable 80-
It is determined that one or both of 1 and the optical fiber cable 80-2 are abnormal. Even during the loopback test by the loopback tester 709, upstream communication from the relay device 90 to the terminal device 70 and downward communication from the terminal device 70 to the relay device 90. Therefore, when the return test reception signal signal is not returned and input during the above-mentioned return test, whether the upstream transmission signal transmitted from the relay device 90 side is received as the upstream reception signal mode at the terminal device 70 side. Whether or not the terminal device 70 detects and determines,
If the relay device 90 detects and determines whether or not the transmission signal LA transmitted from the relay device side is received as a downlink reception signal on the relay device 90 side, the optical fiber cable 80-
1 or the optical fiber cable 80-2, or both are abnormal, or the optical fiber cable 80-
1. Whether the inside of the terminal station device 70 other than the optical fiber cable 80-2 or the inside of the relay device 90 is abnormal can be discriminated and discriminated.

[0011]

The optical subscriber system monitoring method, which is the first conventional technique, transmits the normal transmission signals, that is, the downstream optical signal power and the upstream optical signal power in the optical connector 301 and the optical connector 305. Shuts off
Communication cannot be performed between the upper device and the lower device via the first unit and the second unit. That is, the loopback test is limited to the case where it is not necessary to communicate between the upper device and the lower device.

In the optical subscriber system monitoring method which is the second technique, the loopback test is performed when the power of the in-home termination device 60 is off, so naturally the inter-station termination device 4 is used during this period.
Communication between the higher-level device and the lower-level device via 0 and the home terminating device 60 cannot be performed. That is, the loopback test is limited to the case where it is not necessary to communicate between the upper device and the lower device.

Further, in the optical subscriber system monitoring method of the third conventional technique, the optical transmission system of the optical fiber cable 80-1 side is used as the active system, and the optical fiber cable 8 is used.
If the optical receiving system on the 0-2 side is operated as a standby system, communication between the upper device and the lower device including the terminal device 70 and the relay device 90 can be always performed without interruption during the loopback test. However, two optical transmission / reception systems for both-way transmission are required.

[0014]

According to the optical subscriber system monitoring method of the present invention, bidirectional communication between a station upper device and a subscriber lower device through both optical transmission lines via a center station unit and a subscriber unit. In the optical subscriber system monitoring method for communication, the center station unit folds a downlink transmission signal input from a station side upper device by combining it with an uplink transmission signal from the subscriber side lower device in the subscriber unit. Signal processing such as conversion into a burst signal output at a predetermined time interval necessary for conversion, and the downlink transmission signal converted into the burst signal into an optical signal for optical downlink transmission signal Is output to the downlink optical transmission line of the bidirectional transmission line, and the subscriber unit is the center station unit input through the downlink optical transmission line. Of the optical downlink reception signal from the center station unit that has taken in the optical downlink transmission signal as an optical downlink reception signal into its own unit and has received the uplink transmission signal input from the subscriber side lower device into its own unit. A signal processing such as converting into a burst signal output at a predetermined time interval necessary for folding connection with a signal, and converting the upstream transmission signal converted into the burst signal into an optical signal; Optical upstream transmission signal is output, and the first optical upstream transmission signal and the optical downstream transmission signal taken into the own unit are time-divisionally coupled to upstream optical transmission of the optical bidirectional transmission path. The second optical upstream transmission signal that is output from the subscriber unit within the subscriber unit and is output to the center station unit as a second optical upstream transmission signal. Monitoring to monitor the status of the optical bidirectional transmission path.

Further, the optical subscriber system monitoring method of the present invention performs signal processing such as outputting the first downlink transmission signal from the station side host device at a predetermined time interval necessary for loopback in bidirectional transmission. And a second downlink transmission signal processing means for outputting a second downlink transmission signal, and the second downlink transmission signal from the downlink transmission signal processing means is converted from an electrical signal to an optical signal to output an optical downlink transmission signal. First transmission line
First optical transmitting means for sending to the optical transmission line of the first optical transmission line and the first optical upstream transmission signal input from the second optical transmission line of the optical bidirectional transmission line, First optical receiving means for outputting one upstream reception signal, and a predetermined signal form necessary for transmitting the first upstream reception signal from the first optical reception signal means to the station side upper device Upstream signal processing means for performing signal processing on the second upstream reception signal f and outputting the second upstream reception signal f to the station side host device, the first upstream reception signal from the first optical receiving means and the downstream transmission. The transmission / reception signal comparison / determination means for monitoring the state of the optical bidirectional transmission path by the second downlink transmission signal from the signal means and outputting the first state monitoring signal, and the first optical reception means. The state of the second optical transmission line is monitored by the first upstream reception signal. A reception signal detecting means for outputting a second condition monitoring signals, the first from the reception signal comparison decision means
A center station unit having a state determining signal for determining the state of the optical bidirectional transmission line from the state monitoring signal of 1) and a second state monitoring signal from the received signal detecting means and outputting a state determining signal; Light for branching the optical downlink transmission signal input from the first optical transmission means of the center station unit 1 through the first optical transmission line to output a first optical reception signal and a second optical reception signal. Branching means, second optical receiving means for converting the first optical received signal from the optical branching means from an optical signal into an electrical signal and outputting a first downlink received signal, and the second optical receiving The first downlink received signal from the means is processed into a predetermined signal form necessary for transmitting to the subscriber side lower device, and a second downlink received signal is output and sent to the subscriber side lower device. Downlink reception signal processing means, and the subscriber side lower order And outputs the second upstream transmission signal by performing signal processing such as outputting the first upstream transmission signal from the storage unit at a predetermined time interval necessary for loop-back coupling with the second optical reception signal in bidirectional transmission. Upstream transmission signal processing means, and second optical transmission means for converting the second upstream transmission signal of the upstream transmission signal processing means from an electrical signal to an optical signal to output a second optical upstream transmission signal. , The second
The second optical upstream transmission signal from the second optical transmission means of the optical transmission means is combined with the second optical reception signal of the optical branching means.
A subscriber unit having an optical coupling means for outputting the optical upstream transmission signal and transmitting it to the second optical transmission line.

Further, in the optical subscriber system monitoring method of the present invention, the transmission / reception signal comparison / determination means compares the data or level of the first upstream reception signal and the second downstream transmission signal or the data and level. judge.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. Referring to FIG. 1 showing one embodiment of the present invention, an input terminal A
Downstream transmission signal a from the station side upper device input through
From the downlink transmission signal processing circuit 10 and the downlink transmission signal processing circuit 40, which performs signal processing such as conversion into a burst-like signal output at a predetermined time interval necessary for loopback and outputs as a downlink transmission signal b. Light composed of a semiconductor laser or a light emitting element such as a light emitting diode for converting t from an electric signal into an optical signal having a wavelength of λ1 and outputting the optical downstream transmission signal c to the optical fiber cable 2-1 and sending it to the subscriber side. A transmission circuit 11 and an avalanche photodiode or pin photodiode for converting the optical upstream transmission signal d of wavelength λ1 input from the subscriber side through the optical fiber cable 2-2 into an electrical signal and outputting the upstream reception signal e. Optical receiving circuit 12 including a light receiving element of the above, and signal processing necessary for sending the upstream reception signal e from the optical receiving circuit 12 to the host side host device. And outputs it as an upstream reception signal f and sends it to the higher-level equipment on the station side through the output terminal D, data of the downstream transmission signal b input from the downstream transmission signal processing circuit 10, and the optical reception circuit 12. From the downlink transmission signal processing circuit 10 and the data comparison and determination circuit 14 that compares the data of the upstream reception signal e input from the Level of transmission signal b and optical receiving circuit 12
A level comparison / determination circuit 15 that compares the level of the upstream reception signal e input from
An upstream reception signal detection circuit 16 that detects the presence or absence of an upstream reception signal e input from the optical receiving circuit 12 and outputs an upstream reception detection signal i, and a data determination signal g input from the data comparison determination circuit 14 and a level comparison Level determination signal h input from determination circuit 15 and upstream reception signal detection circuit 16
A failure determination circuit 17 for determining an abnormality in the optical fiber cable 2-1 and the optical fiber cable 2-2 based on the upstream reception detection signal i input from the device, outputting an alarm signal j, and notifying the outside through the output end E. A center station unit 1 having an optical fiber cable 2-1; an optical downlink signal c having a wavelength λ1 from the optical transmission circuit 11 of the center station unit 1 is branched, and one is used as an optical downlink reception signal k. Direction output and the other output to the optical fiber cable 31 for return as the optical return reception signal m, and the optical downlink reception signal k from the optical branch circuit 30 is converted from an optical signal to an electrical signal and then transmitted. An optical receiving circuit 32 that includes a light receiving element such as an avalanche photodiode or a pin photodiode for outputting the received signal n, and the optical receiving circuit 32 receives the optical signal. A downlink received signal processing circuit 33 for performing signal processing necessary for sending the downlink received signal n to the subscriber lower device, outputting it as a downlink received signal o, and sending it to the subscriber lower device through the output terminal B; A burst-like signal or the like output at a predetermined time interval necessary for returning the upstream transmission / reception signal p from the subscriber side lower device input through the terminal C to the optical return reception signal m from the optical branching circuit 30 in a time division manner. The upstream transmission signal processing circuit 34 that performs signal processing such as conversion into an upstream transmission signal q, and the upstream transmission signal g from the upstream transmission signal processing circuit 34 is converted from an electrical signal to an optical signal and has a wavelength of λ1. The optical transmission circuit 35 including a semiconductor laser or a light emitting element such as a light emitting diode that outputs the optical upstream transmission signal γ, and the optical fiber cable 3 for the optical upstream transmission signal γ from the optical transmission circuit 35. The optical return reception signal m from the optical branching circuit 30 input via 1 is returned and combined to output as an optical upstream transmission signal d of wavelength λ1 to the optical fiber cable 2-2 and sent to the optical receiving circuit 12 of the center station unit 1. A subscriber unit 3 having an optical coupling circuit 36 for

Referring to FIG. 2 in combination with FIG. 1,
In the downlink transmission signal processing circuit 10, the downlink transmission signal a inputted from the station side through the input terminal A has downlink data having a predetermined time width T ₂ and downlink data and downlink data are mutually one time slot T. A downlink transmission signal processing circuit that is converted into an intermittent signal having a time interval of T ₃ between _{1 and} is subjected to signal processing suitable for time division combination with the uplink transmission signal q at the time of folding and output as a downlink transmission signal b. The downstream transmission signal b from 10 is converted from an electric signal into an optical signal in the optical transmission circuit 11 and is output to the optical fiber cable 2-1 as the optical downstream transmission signal c of the wave inlet 1 to branch the optical signal of the subscriber unit 3. It is sent to the circuit 30. The optical downlink transmission signal c input to the optical branch circuit 30 of the subscriber unit 3 is branched into two in the optical branch circuit 30, while it is input to the optical reception circuit 32 as an optical downlink reception signal k and the downlink reception signal n of the electrical signal. Is converted into the received signal processing circuit 33, and the downlink received signal processing circuit 33 further performs necessary signal processing for sending it to the subscriber lower-level device and sends it as a downlink received signal o to the subscriber lower-level device. It is sent to the subordinate device on the subscriber side. The other optical return reception signal m, which is branched in the optical branching circuit 30, is output to the optical fiber cable 31 for returning and is sent to the optical coupling circuit 36. Here, the optical coupler 36
The optical return signal m from the optical branching circuit 30 input to is delayed by time t _{1 with} respect to the downlink transmission signal b. This delay time t ₁ mainly occurs in the optical fiber cable 2-1. Further, the upstream transmission signal p from the subscriber side lower device input through the input terminal C is the upstream data and the upstream data having a predetermined time width T ₂ in the same manner as the downstream transmission signal b in the upstream transmission signal processing circuit 34. And the uplink data of T ₃ during one time slot T ₁
Is converted into an intermittent signal having a time interval of, and is subjected to signal processing suitable for being time-divisionally combined with the downlink transmission signal b at the time of returning, and output as an uplink transmission signal r. The upstream transmission signal r from the upstream transmission signal processing circuit 34 is the optical transmission circuit 35.
At, the electrical signal is converted into an optical signal of wavelength λ1 and output as an upstream optical transmission signal r, which is supplied to the optical coupling circuit 36. The optical return reception signal m from the optical branching circuit 30 and the optical upstream transmission signal r from the optical transmission circuit 35, which are input to the optical coupling circuit 36, are time-divisionally combined in the optical coupling circuit 36, and the return data and the upstream data, The upstream data and the return data, ... Are arranged in tandem with a time width t ₂ at substantially equal intervals.

That is, the time interval between the end of the downlink data and the start of the next uplink data is t ₃ and the uplink data and the uplink data are combined so that they do not overlap each other when they are combined. The optical fiber cable 2 is arranged such that the time interval between the end of the data and the start of the next downlink data is t _4, and the return data and the uplink data are arranged in tandem with a time width t ₂ at substantially equal intervals. A delay of -1 is also taken into consideration in advance, and predetermined signal processing is performed between the downlink transmission signal processing circuit 10 and its station side upper apparatus and between the uplink transmission signal processing circuit 34 and its subscriber side lower apparatus. The optical upstream transmission signal d from the optical coupling circuit 35, in which the return data and the upstream data are arranged in tandem with each other and output, is sent to the optical receiving circuit 12 of the center station unit 1 through the optical fiber cable 2-2. The optical upstream transmission signal d from the optical coupling circuit 36 of the subscriber unit 3 input to the optical receiving circuit 12 is converted from an optical signal of wavelength λ1 into an electrical signal and output as an upstream reception signal e, and an upstream reception signal processing circuit 13 , Data comparison / determination circuit 14 and upstream reception signal detection circuit 16 are supplied. The upstream reception signal e input to the upstream reception signal processing circuit 13 is subjected to signal processing required for transmission to the station side upper apparatus and is transmitted to the station side upper apparatus as an upstream reception signal f through the output terminal D. Here, the data comparison / determination circuit 1
Reference numeral 4 detects the presence or absence of return data of the upstream reception signal e input from the optical circuit 12 and compares the return data with the downlink data of the downlink transmission signal b input from the downlink transmission signal processing circuit 10. Matching / mismatching of both data is judged, and if “matching”, it means that the return is normal. The data determination signal g is output, and when the data do not match, the data determination signal g indicating that folding is abnormal is output and supplied to the failure determination circuit 17. Further, the level comparison / determination circuit 15 detects the presence / absence of folding data of the upstream reception signal e input from the optical receiving circuit 12, and detects the folding data and the downlink data of the downlink transmission signal b input from the downlink transmission signal processing circuit 10. When the return data is “present” and the return data level is lower than the downlink data level, it indicates that the return is normal. The level determination signal h is output, and when the return data is “absent”, the level determination signal h indicating that the return is abnormal is output and the failure determination circuit 17 is output.
Supply to. Here, since the return data input to the level comparison circuit 15 is the downlink data of the downlink transmission signal b originally output from the downlink transmission processing circuit 10, the optical fiber cable 2- is input until it is input to the level comparison circuit 15.
1, each of the optical branch circuit 30, the optical coupling circuit 36, and the optical fiber cable 2-2 suffers a loss, so that the level is obviously lower than the original level of the downlink data. Next, the upstream reception signal detection circuit 16 uses the optical reception circuit 12
The presence / absence of upstream data of the upstream reception signal e input from is detected, and when the upstream data is “present”, the upstream reception detection signal i indicating that the optical fiber 2-2 is normal is output, and the upstream data is detected. When is "None", the optical fiber cable 2-
The upstream reception detection signal i indicating that 2 is abnormal is output and supplied to the failure determination circuit 17. The failure determination circuit 17
The level determination signal h is input from the data determination signal h input from the data comparison determination circuit 14, the level determination signal h input from the level comparison determination circuit 15, and the upstream reception detection signal i input from the upstream reception signal detection circuit 16. And the data determination signal g is a signal indicating that it is normal after being switched, it is determined that both the optical fiber cable 2-1 and the optical fiber cable 2-2 are normal, and
When the level determination signal h and the data determination signal g are signals indicating an abnormal return, and when the upstream reception detection signal i is a signal which regards the optical fiber cable 2-2 as normal, the optical fiber cable 2 is detected. -1 outputs a determination signal j that is abnormal, and when the upstream reception detection signal i is a signal that considers the optical fiber cable 2-2 to be abnormal, only the optical fiber cable 2-2 is abnormal or optical. Both the fiber cables 2-1 also output a determination signal j that is considered to be abnormal.

[0020]

EFFECTS OF THE INVENTION By performing signal processing so that downlink data of a downlink transmission signal and uplink data of an uplink transmission signal are arranged in a time-divisional cascade at the time of aliasing connection, normal bidirectional communication is not affected and is always maintained. It is possible to monitor the state of the bidirectional transmission path, and when an abnormality occurs, it is possible to promptly detect the abnormality and notify the abnormality.

[Brief description of drawings]

FIG. 1 is a block diagram showing an optical subscriber system monitoring method according to an embodiment of the present invention.

FIG. 2 is a timing chart for explaining the operation of the optical subscriber system monitoring method of the embodiment.

FIG. 3 is a block diagram showing a first conventional example.

FIG. 4 is a block diagram showing a second conventional example.

FIG. 5 is a block diagram showing a third conventional example.

[Explanation of symbols]

 1 Center Station Unit 10 Optical Transmission Circuit 11 Optical Reception Circuit 12 Timing Circuit 13, 14 Buffer Circuit 15 Data Comparison Circuit 16 Level Comparison Circuit 17 Buffer Circuit 18, 19 Judgment Circuit 2-1, 2-2 Optical Fiber Cable 3 Subscriber Unit 30 Optical Branch Circuit 31 Optical Reception Circuit 32 Reception Signal Processing Circuit 33 Transmission Signal Processing Circuit 34 Optical Transmission Circuit 35 Optical Coupling Circuit 4 Center Station Unit 40 Optical Reception Circuit 41 Optical Coupler 42 Optical Reception Circuit 43 Timing Circuit 44, 45 Buffer Circuit 46 Data comparison circuit 47 Level comparison circuit 48 Buffer circuit 49 Judgment circuit 401 Judgment circuit 5 Optical fiber cable 6 Subscriber unit 60 Optical coupler 61 Optical branch circuit 62 Optical reception circuit 63 Received signal processing circuit 64 Transmitted signal processing circuit 65 Optical transmission circuit 66 Light phi Cable 67 optical coupling circuit a, b downstream transmission signal c optical downstream transmission signal d optical upstream transmission signal e upstream reception signal f upstream reception signal g data determination signal h level determination signal i upstream reception signal j warning signal k optical downstream reception signal m optical return reception signal n, o downlink reception signal p, q upstream transmission signal r optical upstream transmission signal

Front Page Continuation (72) Inventor Tetsuya Suzuki 1-4-2 Mita 1-42 Minato-ku, Tokyo NEC Transmission Engineering Co., Ltd.

Claims (3)

[Claims] 1. An optical subscriber system monitoring system in which an upper apparatus of a station and a lower apparatus of a subscriber bidirectionally communicate with each other through an optical transmission line via a center station unit and a subscriber unit, wherein the center station unit comprises: , A burst-like output that is output at a predetermined time interval necessary for combining the downlink transmission signal input from the station side upper device with the uplink transmission signal from the subscriber side lower device in the subscriber unit and returning the same. A signal processing such as conversion into a signal is performed, the downlink transmission signal converted into the burst signal is converted into an optical signal, and an optical downlink transmission signal is output to output a downlink optical transmission path of the bidirectional transmission path. The subscriber unit sends the optical downlink transmission signal from the center station unit, which is input through the downlink optical transmission line, as an optical downlink reception signal. At a predetermined time interval necessary for loopback coupling of the upstream transmission signal input from the subscriber side lower device with the optical downstream reception signal from the center station unit captured in the own unit. Signal processing such as conversion into an output burst signal is performed, and the upstream transmission signal converted into the burst signal is converted into an optical signal to output a first optical upstream transmission signal, and the first optical upstream transmission signal is output. The optical upstream transmission signal and the optical downstream transmission signal taken into the own unit are time-divisionally coupled and output to the upstream optical transmission path of the optical bidirectional transmission path to obtain a second optical upstream transmission signal. Sending the signal to the center station unit, and monitoring the second optical upstream transmission signal sent from the subscriber unit in the subscriber unit to monitor the state of the optical bidirectional transmission path. Optical subscriber system monitoring system to butterflies. 2. A downlink for outputting a second downlink transmission signal by performing signal processing such as outputting the first downlink transmission signal from the station side upper device at a predetermined time interval necessary for folding in bidirectional transmission. Transmission signal processing means, and converting the second downlink transmission signal from the downlink transmission signal processing means from an electric signal to an optical signal to output an optical downlink transmission signal to the first optical transmission path of the bidirectional transmission path. First optical transmitting means for transmitting,
First optical receiving means for converting the first optical upstream transmission signal input from the second optical transmission path of the optical bidirectional transmission path from an optical signal to an electrical signal and outputting a first upstream reception signal , And outputs a second upstream reception signal f by performing signal processing on the first upstream reception signal from the first optical reception signal means into a predetermined signal form required for transmission to the station side upper device. Then, the optical signal is generated by the upstream signal processing means for transmitting to the station side upper device, the first upstream reception signal from the first optical receiving means and the second downstream transmission signal from the downstream transmission signal means. Transmission / reception signal comparison / determination means for monitoring the status of the bidirectional transmission path and outputting a first status monitoring signal, and the second optical transmission path by the first upstream reception signal from the first optical reception means. Signal detection that monitors the status of the device and outputs the second status monitoring signal And a first state monitoring signal from the transmission / reception signal comparison / determination means and a second state monitoring signal from the reception signal detection means to determine the state of the optical bidirectional transmission path and output a state determination signal. A center station unit having a failure determining means for controlling the optical downlink transmission signal input from the first optical transmitting means of the center station unit 1 through the first optical transmission line to branch the first optical signal. An optical branching unit that outputs a received signal and a second optical received signal; and a first output unit that outputs the first downlink received signal by converting the first optical received signal from the optical branching unit from an optical signal to an electrical signal. Two
Light receiving means and the first light receiving means from the second light receiving means.
Downlink reception signal processing means for performing signal processing into a predetermined signal form necessary for transmitting the downlink reception signal of No. 1 to the subscriber side lower device, outputting a second downlink reception signal, and transmitting the second downlink reception signal to the subscriber side lower device. And a signal processing such as outputting the first upstream transmission signal from the subscriber side lower device at a predetermined time interval necessary for loopback coupling with the second optical reception signal in bidirectional transmission, An upstream transmission signal processing means for outputting the second upstream transmission signal, and a second optical upstream transmission signal for converting the second upstream transmission signal of the upstream transmission signal processing means from an electric signal to an optical signal. 2 optical transmission means,
The second optical upstream transmission signal from the second optical transmission unit is combined with the second optical reception signal from the optical branching unit to output the first optical upstream transmission signal to output the second optical upstream transmission signal. A subscriber unit having an optical coupling means for sending to an optical transmission line; and an optical subscriber system monitoring method. 3. The transmission / reception signal comparison / determination means compares and determines the data or the level or the data and the level of the first upstream reception signal and the second downstream transmission signal. Optical subscriber system monitoring method.