JP2014039229A - Optical line terminating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical line terminating device which can block the signal output of an optical line terminating device related to troubles and can dissolve a communication failure without the need for much labor and high costs.SOLUTION: An optical line terminating device 40 performing two-way communication with a broadcast center comprises: an optical transmitting/receiving terminal 41 as optical signal receiving means for receiving an optical signal; a PD 42 which converts the optical signal received by the optical transmitting/receiving terminal 41 into an electric signal; an electrical transmitting terminal 43 which transmits the electric signal converted by the PD 42; an electrical receiving terminal 44 which receives the electric signal; an LD 45 which converts the electric signal received by the electrical receiving terminal 44 into an optical signal; the optical transmitting/receiving terminal 41 as optical signal transmitting means for transmitting the optical signal converted by the LD 45; and an opening/closing switch 49 for blocking the transmission of the optical signal when it is determined that there is failure in an abnormality determining section 48a for determining the presence or absence of a failure of a device such as the optical line terminating device 40.

Description

  The present invention relates to photoelectric conversion that receives various signals as optical signals and converts them into electrical signals, and an optical line terminator that performs electro-optical conversion that receives various signals as electrical signals and converts them into optical signals.

  In recent years, with the progress of optical communication technology, FTTH (Fiber To The Home), which is a data communication service for homes using optical fibers, is becoming popular in ordinary homes. According to this optical transmission system, since repeatless transmission of about several tens of kilometers is possible, the transmission system can be easily widened. In general, this optical transmission system connects an optical transceiver and an optical amplifier arranged on the center side to an optical network unit (ONU: Optical Network Unit) arranged on the receiver side via an optical cable. Configured. In such an optical transmission system, an optical cable is distributed to a plurality of optical cables by an optical distributor provided in the path, and is connected to a corresponding plurality of optical line terminators. Then, the optical transceiver converts the RF signal into an optical signal and transmits it, the optical amplifier amplifies this optical signal, and transmits this optical signal to the optical distributor via a long-distance transmission path using an optical cable. The optical signal distributed by the optical distributor is transmitted to each optical line terminating device. In this optical line terminating device, the optical signal is converted into an electric signal (RF signal) and output to each receiving terminal such as a TV receiver.

  Among such optical line terminators, an optical transmission system including an optical line terminator (R-ONU: Radio Frequency Optical Network Unit) that enables bidirectional communication between the center side and the receiver side is a receiving terminal. Uplink signals are transmitted from to the center side. Specifically, each receiving terminal transmits a broadcast signal to a corresponding optical line termination device, and each optical line termination device converts an electrical signal (RF signal) into an optical signal and transmits it to the optical distributor, The optical distributor combines the broadcast signals transmitted from the optical line terminator, and transmits the combined broadcast signals to the optical transceiver and optical amplifier disposed on the center side through a long-distance transmission path using an optical cable. , Enabling two-way communication between the center side and the receiver side.

  Here, if multiple receiving terminals transmit upstream broadcast signals to the center at the same time, the broadcast signals collide with each other when mixing the broadcast signals in the optical distributor, resulting in communication failure. Resulting in. Therefore, time division control (TDMA: Time Division Multiple Access) for preventing collision between broadcast signals is performed by controlling the timing at which each receiving terminal transmits broadcast signals and the transmission amount of broadcast signals (for example, Patent Document 1).

JP 2008-042525 A

  However, for example, when one of the plurality of optical line terminators fails, it is conceivable that the failed optical line terminator continues to transmit an optical signal to the center side. In addition, when a receiving terminal that is a communication device located downstream of the optical line terminator fails, the failed receiving terminal continues to transmit an electrical signal to the optical line terminator. It is conceivable that the corresponding optical line terminator continues to transmit optical signals to the center side. In these cases, the upstream broadcast signal is transmitted from the failed optical line terminator regardless of the time-divided timing. Therefore, the broadcast signal and other optical line terminators are transmitted. May collide with a broadcast signal and cause a communication failure. In order to eliminate such a communication failure, a remote control device capable of remotely controlling the optical line terminator is installed on the center side, and the optical line terminator that continues to transmit electric signals is stopped. There is an announcement broadcasting system that made it possible. However, even in such an announcement broadcasting system, the center side cannot determine which optical line terminator is out of order. For this reason, it is necessary to take measures to stop the connected optical line terminators one by one, and it takes time and money to identify the faulty optical line terminator and to eliminate the communication trouble.

  In addition, if the downstream transmission line from the optical distributor to the failed optical line termination device is disconnected for some reason, the failed optical line termination device cannot be remotely controlled and stopped. It was in a situation where the obstacle could not be resolved.

  The present invention has been made in view of the above, and when a faulty optical line terminator continues to transmit an optical signal to the center side, or further remotely controls a faulty optical line terminator To provide an optical line terminator that can cut off the signal output of a faulty optical line terminator and eliminate communication troubles even when it is impossible With the goal.

  In order to solve the above-described problems and achieve the object, an optical line termination device according to claim 1 is an optical line termination device that performs two-way communication of optical signals with a broadcasting center. An optical signal receiving means for receiving the light, a photoelectric conversion means for converting the optical signal received by the optical signal receiving means into an electric signal, an electric signal transmitting means for transmitting the electric signal converted by the photoelectric conversion means, An electric signal receiving means for receiving a signal, an electric light converting means for converting the electric signal received by the electric signal receiving means into an optical signal, an optical signal transmitting means for transmitting the optical signal converted by the electric light converting means, An abnormality that determines whether there is an abnormality in the optical line termination device or a device connected to the downstream side of the optical line termination device that may affect the transmission state of the upstream signal by the optical line termination device Comprising a constant section and a light transmission blocking means for blocking the transmission of the optical signal by the optical signal transmission unit when determining abnormality exists and in the abnormality judgment means.

  Further, an optical line termination device according to claim 2 is the optical line termination device according to claim 1, further comprising an optical signal level measurement unit that measures a level of an optical signal received by the optical signal reception unit, The abnormality determining means determines that there is an abnormality when the level of the optical signal received by the optical signal level measuring means is below a reference level.

  An optical line termination device according to claim 3 is an optical transmission device according to claim 1, wherein the optical signal transmission unit measures the continuous transmission time of the optical signal by the optical signal transmission means. Time measurement means is provided, and the abnormality determination means determines that there is an abnormality when the continuous transmission time of the optical signal measured by the optical transmission time measurement means exceeds a reference time.

  According to a fourth aspect of the present invention, there is provided the optical line terminator according to the third aspect, comprising: a reference time storage unit that stores the reference time; and a remote control unit that is installed in the broadcast center. Remote control means for transmitting a remote control signal for controlling the reference time, and when it is determined that the optical signal receiving means has received the remote control signal transmitted from the remote control means, Reference time control means for controlling the reference time stored in the reference time storage means based on a remote control signal.

An optical line termination device according to claim 5 is transmitted from a remote control device for remotely operating the optical line termination device according to any one of claims 1 to 4. Carrier level measuring means for measuring the carrier level of the received signal,
The abnormality determination means determines that there is an abnormality when the carrier level measurement means cannot detect the carrier level.

  The optical line termination device according to claim 6 is the optical line termination device according to any one of claims 1 to 5, wherein the abnormality determination unit determines that there is an abnormality or the optical transmission cutoff. When the means is blocking the transmission of the optical signal, a display means for displaying the fact is provided.

  According to the optical line termination device according to claim 1, when it is determined that there is an abnormality in the optical line termination device, it is possible to shut off the signal output of the optical line termination device having an abnormality. Even if the optical line termination equipment continues to transmit optical signals to the broadcasting center, or even when it is impossible to remotely control the failed optical line termination equipment, it will not be troublesome and costly Thus, the signal output of the optical line terminator can be cut off, and the communication failure can be solved.

  According to the optical line terminator according to claim 2, when the level of the optical signal received by the optical signal receiving means does not reach the reference level, an abnormality has occurred in the optical line terminator. Because it is possible to block the optical signal output of the optical line terminator, the failure of transmitting the optical signal to the broadcasting center even though the optical signal is not transmitted from the broadcasting center Therefore, it is possible to easily cut off the signal output of the optical line terminating device causing the communication failure.

  According to the optical line terminator of claim 3, when the optical line terminator continues to transmit the optical signal continuously to the broadcasting center for a predetermined time or more, there is an abnormality in the optical line terminator. Because it is possible to determine that it has occurred and cut off the optical signal output of the optical line terminator, due to the failure of continuously transmitting the optical signal to the broadcast center for a predetermined time or longer It is possible to easily cut off the signal output of the optical network unit causing the communication failure.

  According to the optical line termination device of the fourth aspect, since the reference time stored in the optical line termination device can be remotely controlled by the remote control means installed in the broadcasting center, it is easy by remote operation. It is possible to change the setting to a reference time suitable for the communication state.

  According to the optical line termination device according to claim 5, when the carrier level of the signal transmitted from the remote control device cannot be detected, it is determined that an abnormality has occurred in the optical line termination device. Since it is possible to cut off the optical signal output of the optical line termination device, it is possible to easily cut off the signal output of the optical line termination device that is likely to cause a communication failure due to a failure of the receiving system or the like. It is possible.

  According to the optical line termination device according to claim 6, when it is determined that there is an abnormality in the abnormality determination unit or when the transmission of the optical signal is blocked in the optical transmission blocking unit, this is notified to the user. Since it is possible to notify by displaying, it is possible to notify the user of the abnormality of the optical line terminating device in an earlier and simple manner.

It is the block diagram which showed the notification broadcasting system which concerns on this Embodiment 1 functionally. It is the block diagram which showed the notification broadcasting system which concerns on this Embodiment 2 functionally.

  Hereinafter, embodiments of a notification broadcasting system according to the present invention will be described in detail with reference to the accompanying drawings. [I] First, the basic concept common to each embodiment was explained, then [II] the specific contents of each embodiment were explained, and [III] Finally, modifications to each embodiment were explained. To do. However, the present invention is not limited to each embodiment.

[I] Basic concept common to the embodiments First, the basic concept of the embodiment will be described. The present invention relates to an announcement broadcast system that receives broadcast signals transmitted from a broadcast center at each dwelling unit or the like. Here, the “notification broadcasting system” is a system for performing various types of notification broadcasting (and possibly TV broadcasting) from a broadcasting center to a plurality of dwelling units, etc., and is a center arranged on the broadcasting center side. And a transmission system that transmits a broadcast signal transmitted from the center device to the receiver, and an optical line termination device provided in the path of the transmission system. Yes. Here, the “broadcast center” is a transmitting station equipped with a center device, and includes, for example, a government office, a fire department, a CATV station, and the like. A “center device” is a device that transmits a broadcast signal. In addition, the “optical line termination device” is a device provided in the path of the transmission system. The optical signal transmitted from the center device is photoelectrically converted and transmitted to the receiver, and transmitted from the receiver. The R-ONU enables bidirectional communication between the center side and the receiver side by converting an electric signal into light and transmitting it to the center device. The “receiver” is a device that is provided in each dwelling unit and performs two-way communication of a broadcast signal with a broadcast center, and has a concept including, for example, a TV receiver, a notification broadcast receiver, and the like. In addition, although the installation object of the optical line termination apparatus which concerns on this Embodiment is arbitrary, below, the case where it installs in the outdoors of a dwelling unit is demonstrated as an example. The “broadcast signal” is a signal transmitted for broadcasting, and includes, for example, a notification broadcast signal, a TV broadcast signal, a radio broadcast signal, and the like. In addition, this broadcast signal is a concept that includes both an optical signal transmitted and received between the center device and the optical line terminator and an electric signal transmitted and received between the optical line terminator and the receiver. In the following, broadcast signals, optical signals, and electrical signals are distinguished and referred to as necessary.

[II] Specific Contents of Each Embodiment Next, specific contents of each embodiment according to the present invention will be described.

[Embodiment 1]
First, the first embodiment will be described. The present embodiment is an embodiment of an announcement broadcasting system including an optical line termination device that performs abnormality determination based on the reception level of an optical signal. First, an outline of the present embodiment will be described.

  Usually, in an announcement broadcasting system based on two-way communication, if the optical line termination device is operating normally, the optical line termination device has not received a downstream broadcast signal from the center device, There is no such a situation that the optical line terminating device continues to transmit the upstream broadcast signal unilaterally. However, when an optical line termination device or the like is out of order, the optical line termination device unilaterally rises even though the optical line termination device related to this failure has not received a downlink broadcast signal from the center device. It is possible that the broadcast signal will continue to be transmitted. The optical line terminator according to the present embodiment is an optical line terminator that is effective for such a failure.

(Constitution)
Next, the configuration of the notification broadcasting system 1 according to this embodiment will be described. FIG. 1 is a block diagram functionally conceptually showing an announcement broadcasting system 1 according to the present embodiment. As shown in FIG. 1, the notification broadcasting system 1 transmits a broadcast signal transmitted from a center device 10 disposed on the broadcast center side, a receiver 30 disposed in each dwelling unit, and the center device 10 to the receiver 30. Transmission line 20 and an optical line terminator 40 provided in the path of the transmission line 20. Below, the structure of the center apparatus 10, the transmission system 20, the receiver 30, and the optical line terminal device 40 is demonstrated in order later in detail. In addition, except the structure which mentions specially, the center apparatus 10, the transmission system 20, the receiver 30, and the optical line terminal device 40 can be comprised similarly to the conventional notification broadcasting system.

(Configuration-Center device)
Among these, the center apparatus 10 is a transmission means for transmitting a notification broadcast signal, and includes an operation unit 11, a display unit 12, a microphone 13, a BGM source 14, a memory 15, a date / time circuit 16, a transmission / reception unit 17, and a control unit 18. It is prepared for.

  The operation unit 11 is an operation unit for performing various operations on the center device 10 and includes, for example, various switches (not shown). The display unit 12 is a display unit for displaying necessary information toward the operator, and includes, for example, a monitor and a display lamp (not shown). The microphone 13 is a voice input means for inputting voice for announcement broadcasting. The BGM source 14 is sound source means that becomes a sound source of background music for announcement broadcasting. The memory 15 is a recording unit that records information necessary for various controls of the center device 10. The date / time circuit 16 is date / time means for outputting date / time information including date and time. The transmission / reception unit 17 is a transmission unit that transmits the notification broadcast signal to the head end 21. The control unit 18 is a control unit that controls each unit of the center device 10 and includes, for example, a CPU (Central Processing Unit) (not shown) and a program that is interpreted and executed on the CPU.

(Configuration-Transmission system)
Next, the transmission system 20 includes a head end 21, an optical transmission line 22 from the head end 21 to the receiver 30 of each dwelling unit, and an optical amplifier 23 and an optical distribution amplifier 24 arranged on the optical transmission line 22. , And an optical distributor 25. The head end 21 is an amplification transmission unit that receives an electrical signal transmitted from the transmission / reception unit 17 of the center apparatus 10, level-amplifies the electrical signal, performs electro-optic conversion, and sends the electrical signal to the optical transmission line 22. The optical transmission line 22 is a transmission line for transmitting a notification broadcast signal, and for example, an optical cable is used. The optical amplifier 23 is an optical amplifying unit that amplifies a signal flowing through the optical transmission line 22. The optical distribution amplifier 24 is optical distribution amplification means that amplifies the signal and distributes the amplified signal toward each dwelling unit. The optical distributor 25 is an optical distribution unit that distributes the signal amplified by the optical distribution amplifier 24 toward each dwelling unit.

  In the above description, only the downlink communication function is shown for the center device 10 and the transmission system 20, but the notification broadcasting system 1 according to the present embodiment performs bidirectional communication between the receiver 30 and the center device 10. Since the notification broadcast system 1 is assumed, a broadcast signal may be transmitted from the receiver 30 toward the center device 10. In this case, a broadcast signal is transmitted from the receiver 30 to the center apparatus 10 to the optical transmission line 22 by a known method. In this case, the optical distributor 25 functions as an optical combiner.

(Configuration-Receiver)
Next, the receiver 30 according to the present embodiment will be described. The receiver 30 is a receiver 30 that receives a broadcast signal transmitted from an optical line terminating device 40 to be described later. The receiver 30 includes, for example, a speaker (not shown) and outputs the received broadcast signal from the speaker. It is possible to broadcast. When the receiver 30 receives a broadcast signal transmitted from the center apparatus 10 via an optical line termination device 40 (to be described later), the receiver 30 transmits the broadcast signal via the optical line termination apparatus 40 by a known method. Reply to the device 10. In this way, the center device 10 and the receiver 30 are connected to each other via the optical line termination device 40 so as to be capable of bidirectional communication.

(Configuration-optical line termination equipment)
Next, the optical line termination device 40 according to the present embodiment will be described. This optical line termination device 40 generally includes an optical transmission / reception terminal 41, a photodiode (hereinafter referred to as PD42), an electrical transmission terminal 43, an electrical reception terminal 44, a light emitting diode (hereinafter referred to as LD45), an optical mixer 46, and an optical reception. A level measurement unit 47, a control unit 48, an open / close switch 49, a display unit 50, and a memory 51 are provided.

  The optical transmission / reception terminal 41 is an optical signal reception unit that receives an optical signal, and is an optical signal transmission unit that transmits an optical signal converted by an LD 45 described later. The optical transmission / reception terminal 41 is connected to the center apparatus 10 via the optical transmission line 22, thereby enabling an optical signal transmitted by the center apparatus 10 to be transmitted to the optical line termination apparatus 40. The optical signal transmitted by the optical line terminating device 40 can be transmitted to the center device 10. In addition, as a specific structure of this optical transmission / reception terminal 41, the structure similar to a well-known optical transmission / reception terminal is employable.

  The PD 42 is a photoelectric conversion unit that converts an optical signal received by the optical transmission / reception terminal 41 into an electric signal. This photoelectric conversion means may be any device as long as it can convert an optical signal into an electric signal.

  The electrical transmission terminal 43 is an electrical signal transmission unit that transmits the electrical signal converted by the PD 42. This electrical reception terminal 44 is connected to the receiver 30 of each dwelling unit via a coaxial cable or the like, and this allows the electrical signal transmitted by the optical line termination device 40 to be transmitted to the receiver 30. . In addition, as a specific structure of this electric transmission terminal 43, the structure similar to a well-known electric transmission terminal is employable.

  The electric receiving terminal 44 is an electric signal receiving means for receiving an electric signal. The electrical reception terminal 44 is connected to the receiver 30 of each dwelling unit via a coaxial cable or the like, and this allows the electrical signal transmitted by the receiver 30 to be transmitted to the optical line terminator 40. . In addition, as a specific configuration of the electric receiving terminal 44, a configuration similar to a known electric receiving terminal can be employed.

  The LD 45 is an electro-optical conversion unit that converts an electric signal received by the electric receiving terminal 44 into an optical signal. The electro-optical conversion means may be any device as long as it can convert an electrical signal into an optical signal.

  The optical mixer 46 is an optical mixing unit that mixes an optical cable that transmits an optical signal to the optical reception level measuring unit 47 and an optical cable that transmits an optical signal from the LD 45. In addition, although the installation position of this optical mixer 46 is not specifically limited, in this Embodiment, it demonstrates as what is installed downstream of the optical transmission / reception terminal 41 in the downstream of the optical transmission / reception terminal 41. FIG. As another configuration, it may be installed upstream of the optical line termination device 40. In this case, an optical transmission terminal and an optical reception terminal are provided in place of the optical transmission / reception terminal 41, and two of these optical transmission terminals and optical reception terminals are laid from the optical transmission line termination device 40 toward the upstream side. A configuration in which the optical cable is mixed by the optical mixer 46 can be employed.

  The optical reception level measurement unit 47 is an optical reception level measurement unit that measures the level of an optical signal received via the optical transmission / reception terminal 41. The installation position of the optical reception level measuring unit 47 is not particularly limited as long as it is a position where the level of the received optical signal can be measured, but in this embodiment, it is in the path between the optical mixer 46 and the PD 42. It is assumed that it is installed. Then, the optical reception level measurement unit 47 measures the level of the optical signal in the path by a known measurement method, and transmits the measured level of the optical signal to the control unit 48 described later. In addition, the level of the optical signal measured in this way is used for an abnormality control process described later.

  The control unit 48 is a control unit that controls each unit of the optical line termination device 40, and includes, for example, a CPU (Central Processing Unit) (not shown) and a program that is interpreted and executed on the CPU. Here, the control unit 48 includes an abnormality determination unit 48a and a control signal transmission unit 48b. Among these, the abnormality determination unit 48a is a device connected to the downstream side of the optical line terminator 40 or the optical line terminator 40 and capable of affecting the transmission state of the upstream signal by the optical line terminator 40. It is an abnormality determination means for determining the presence or absence of abnormality. The abnormality determination unit 48a determines the presence or absence of the abnormality by comparing the optical signal level measured by the optical reception level measurement unit 47 with a reference level stored in a reference level storage unit 51a of the memory 51 described later. Do. The control signal transmitter 48b is a control signal transmitter that transmits an opening / closing command as a control signal to an opening / closing switch 49 described later. A detailed description of each process performed by the control unit 48 will be described later.

  The open / close switch 49 is an optical transmission blocking unit that blocks transmission of an optical signal from the optical transmission / reception terminal 41 when the abnormality determination unit 48a determines that there is an abnormality. The installation position of the open / close switch 49 is not particularly limited as long as it is a position where the transmission of the optical signal by the optical transmission / reception terminal 41 can be cut off, but in the present embodiment, it is between the electric reception terminal 44 and the LD 45. It is assumed that it is installed in the route. When the abnormality determination unit 48a determines that there is no abnormality, the open / close switch 49 maintains a closed state, and in this closed state, an electric signal received by the electric reception terminal 44 is output to an LD 45 described later. The On the other hand, when the abnormality determination unit 48a determines that there is an abnormality, the open state is set, and in this open state, an electric signal received by the electric reception terminal 44 is not output to the LD 45 described later. The predetermined processing performed by the opening / closing switch 49 will be described later.

  The display unit 50 is a display unit that displays when there is an abnormality in the abnormality determination unit 48a or when the transmission of the optical signal is interrupted by the open / close switch 49. The display unit 50 may adopt any configuration as long as it can notify the user of the interruption of the optical signal. For example, the display unit 50 is installed on the outer surface of the casing of the optical line termination device 40. When the abnormality determination unit 48a determines that there is an abnormality, that is, when the transmission / reception of the optical signal is interrupted by the open / close switch 49, the display lamp is turned on to It is possible to notify the interruption of the optical signal.

  The memory 51 is a storage unit that records information necessary for various controls of the optical line termination device 40. Although the specific configuration of the memory 51 is arbitrary, for example, a RAM (Random Access Memory) or a flash memory can be used. The memory 51 according to the present embodiment is roughly configured to include a reference level storage unit 51a, and the reference level storage unit 51a is a reference used as a determination index for the presence or absence of abnormality in an abnormality control process described later. I remember the level.

(Processing-Abnormal control processing)
Next, the abnormality control process performed by the optical line terminating device 40 configured as described above will be described. This abnormality control processing is an optical line termination device 40 or a device connected to the downstream side of the optical line termination device 40 and capable of affecting the transmission state of the upstream signal by the optical line termination device 40 (hereinafter referred to as optical This is a process of determining an abnormality of the line terminating device 40 and the like, and controlling the output of the optical signal of the optical line terminating device 40 based on the determination result.

  First, an outline of the abnormality control process will be described. That is, in the notification broadcasting system 1 premised on two-way communication, when the optical line termination device 40 or the like is operating normally, the optical line termination device 40 has not received a downstream broadcast signal from the center device 10. Nevertheless, the optical line terminating device 40 does not continue to transmit the upstream broadcast signal unilaterally. However, when the optical line terminator 40 or the like is out of order, the optical line terminator 40 is unilaterally transmitted even though the optical line terminator 40 has not received the downlink broadcast signal from the center device 10. It is possible that the broadcast signal will continue to be transmitted. The abnormality control process in the present embodiment is a process for controlling the optical line terminating device 40 that has transmitted a downlink broadcast signal due to a failure of the optical line terminating apparatus 40 or the like.

  Next, specific contents of the abnormality control process will be described. First, the optical reception level measurement unit 47 measures the level of the optical signal received at the optical transmission / reception terminal 41 at all times or at a predetermined interval, and transmits the measured level of the optical signal to the control unit 48. In response to this, the abnormality determination unit 48 a of the control unit 48 compares the level of the optical signal transmitted from the optical reception level measurement unit 47 with the reference level stored in the reference level storage unit 51 a of the memory 51. If the level of the optical signal is below the reference level, the abnormality determination unit 48a determines that the optical line termination device 40 is abnormal, and the control signal transmission unit 48b opens the open / close switch 49. Send a control signal. The open / close switch 49 that has received this open control signal opens the open / close switch 49 and shuts off the output of the electric signal from the electric receiving terminal 44 to the LD 45. In this way, the electrical signal output to the LD 45 is cut off, so that the electrical signal transmitted from the receiver 30 does not reach the LD 45, and the optical line terminating device 40 transmits light to the center device 10. The signal output can be cut off.

  On the other hand, when the level of the optical signal is higher than the reference level, the abnormality determination unit 48a determines that the optical line termination device 40 has no abnormality, and the control signal transmission unit 48b closes the open / close switch 49. Send a control signal. The open / close switch 49 that has received the close control signal closes the open / close switch 49 and transmits an electric signal from the electric receiving terminal 44 to the LD 45. In this way, when no abnormality has occurred, it is possible to normally transmit an electric signal to the LD 45.

  Actually, even if the level of the optical signal measured by the optical reception level measuring unit 47 is lower than the reference level stored in the reference level storage unit 51a of the memory 51, the optical line terminating device 40 or the like fails. Not necessarily what you are doing. For example, when the center device 10 does not transmit a broadcast signal to the optical line termination device 40, the optical signal is not measured in the optical reception level measuring unit 47, and thus it falls below the reference level. It cannot be said that the optical line termination device 40 or the like is out of order. However, in the notification broadcasting system 1 on the premise of bidirectional communication, when the center device 10 does not transmit a broadcast signal to the optical line termination device 40, the optical line termination device 40 transmits an optical signal to the center device 10. Since transmission is unthinkable, in this case, even if an abnormality control process is performed assuming that an abnormality has occurred, there is no problem in communication.

  Further, this reference level can be obtained by experiments or the like, for example, and any value can be adopted. Further, the reference level stored in the reference level storage unit 51a of the memory 51 may be configured to be rewritable so that the reference level can be set according to the use environment.

(Effect of Embodiment 1)
As described above, according to the first embodiment, when it is determined that there is an abnormality in the optical line termination device 40, it is possible to shut off the signal output of the optical line termination device 40 having an abnormality. Even when the optical line terminator 40 continues to transmit an optical signal to the broadcasting center, or when it is impossible to remotely control the faulty optical line terminator 40, there is no need for labor and cost. It is possible to block the signal output of the failed optical line termination device 40, and to eliminate the communication failure.

  If the level of the optical signal received by the optical transmission / reception terminal 41 does not reach the reference level, it is determined that an abnormality has occurred in the optical line termination device 40, and the optical signal from the optical line termination device 40 is detected. An optical line terminator that causes a communication failure due to a failure that transmits an optical signal to the broadcasting center even though the optical signal is not transmitted from the broadcasting center because the signal output can be cut off. Forty signal outputs can be easily cut off.

  Further, when it is determined that there is an abnormality in the abnormality determination unit 48a or when the transmission / reception of the optical signal is blocked by the open / close switch 49, it is possible to notify the user by displaying that fact. Thus, it is possible to notify the user of an abnormality or the like of the optical line terminating device 40 earlier and in a simple manner.

[Embodiment 2]
Next, a second embodiment will be described. The present embodiment is an embodiment of an announcement broadcasting system including an optical line termination device that performs abnormality control based on a continuous transmission time of an optical signal. First, an outline of the present embodiment will be described.

  First, when each optical line terminator transmits an uplink signal to the center apparatus, as described above, time division transmission is performed for each optical line terminator. Specifically, the center device includes a center modem (not shown), the timing at which the center modem transmits an upstream signal to each optical line terminating device, the time to continue transmission, the amount of information of the signal to be transmitted, etc. Assign. Each optical line termination device transmits an uplink signal within the allocated time, so that uplink signals transmitted from the respective optical line termination devices are transmitted to the center apparatus without colliding with each other. In other words, in an optical line termination device in a notification broadcasting system based on two-way communication, if the optical line termination device or the like is operating normally, as described above, within the assigned predetermined time, Therefore, the broadcast signal is not transmitted to the center device beyond that time. However, when an optical line termination device or the like is out of order, it is possible that a broadcast signal is transmitted to the center device over this time. For example, this case corresponds to a case where the optical line termination device continuously transmits a broadcast signal to the center device for a predetermined time or more due to a failure of the optical line termination device. The optical line terminator according to the present embodiment is an optical line terminator that is effective for such a failure. The configuration and procedure of the second embodiment are substantially the same as the configuration and procedure of the first embodiment unless otherwise specified, and this configuration and procedure are substantially the same as those of the first embodiment. The same reference numerals as those used in Embodiment 1 are attached as necessary, and the description thereof is omitted.

(Constitution)
FIG. 2 is a block diagram functionally conceptually showing the notification broadcasting system 2 according to the second embodiment. As shown in FIG. 2, the announcement broadcasting system 2 transmits a center device 60 disposed on the center side, a receiver 30 disposed in each dwelling unit, and a broadcast signal transmitted from the center device 60 to the receiver 30. The transmission system 20 includes an optical line termination device 70 provided in the path of the transmission system 20. Note that the receiver 30 and the transmission system 20 can be configured in the same manner as those in the first embodiment, and thus detailed description thereof will be omitted. In the following, the center device 60 and the optical line termination device 70 are omitted. Will be described.

(Configuration-Center device)
First, the configuration of the center device 60 will be described. The center device 60 is a transmission means for transmitting a notification broadcast signal, and generally includes a remote control unit 61. The remote control unit 61 is a remote control unit that is installed in the center device 60 and transmits a remote control signal for controlling the reference time. Here, the reference time is a time used as an abnormality determination index in an abnormality determination means described later, and is stored in a reference time storage unit 73a of an optical line terminating device 70 described later. The specific configuration of the remote control unit 61 is arbitrary. For example, the remote control unit 61 is configured in the same manner as the operation unit 11 of the center device 60 and is configured so that the reference time of the optical line termination device 70 can be input. A signal including information related to the reference time input by the remote control unit 61 is transmitted to the optical line termination device 70 via the control unit 18, the transmission / reception unit 17, the transmission system 20 and the like of the center device 60. As described above, the center device 60 includes a center modem that assigns optical signal transmission timing and the like to each optical line terminating device 70. This center modem can be configured in the same manner as a conventional center modem. Therefore, the illustration and detailed description thereof are omitted.

(Configuration-optical line termination equipment)
Next, the configuration of the optical line termination device 70 will be described. The optical line termination device 70 is generally configured to include an optical transmission time measurement unit 71, a control unit 72, and a memory 73.

  The optical transmission time measuring unit 71 is an optical transmission time measuring unit that measures the continuous transmission time of the optical signal from the optical transmission / reception terminal 41. Here, the continuous transmission time of the optical signal is a time during which the optical line terminator 70 continues to output the broadcast signal when it outputs the broadcast signal to the center device 60, and is a predetermined value assigned at least by the center modem. It is set as a predetermined time exceeding this time. The installation position of the optical transmission time measuring unit 71 is not particularly limited as long as it can measure the continuous transmission time of the optical signal, but in the present embodiment, between the LD 45 and the optical transmission / reception terminal 41. It is assumed that it is installed in the route between. And the continuous transmission time of an optical signal is measured with a well-known measuring method, and the measured continuous transmission time is transmitted to the control part 72 mentioned later. The continuous transmission time measured in this way is used for an abnormality control process described later.

  The control unit 72 is a control unit that controls each unit of the optical line termination device 70, and is configured in the same manner as the control unit 48 of the first embodiment, except as described below. Here, the control unit 72 includes an abnormality determination unit 72a, a control signal transmission unit 72b, and a reference time rewriting unit 72c. The abnormality determination unit 72a is the presence / absence of an abnormality in the optical line termination device 70 or a device connected to the downstream side of the optical line termination device 70 that may affect the transmission state of the uplink signal by the optical line termination device 70 It is determined that there is an abnormality when the continuous transmission time of the optical signal measured by the optical transmission time measuring unit 71 exceeds the reference time. The abnormality determination unit 72a determines the presence or absence of the abnormality by comparing the continuous transmission time measured by the optical transmission time measurement unit 71 with a reference time stored in a reference time storage unit 73a of the memory 73 described later. Do. Since the control signal transmission unit can be configured in the same manner as in the first embodiment, detailed description thereof is omitted. When it is determined that the optical transmission / reception terminal 41 has received the remote control signal transmitted from the remote control unit 61, the reference time rewriting unit 72c is stored in the reference time storage unit 73a based on the remote control signal. Reference time control means for controlling the reference time. The reference time rewriting unit 72c can rewrite the reference time stored in the reference time storage unit 73a to an arbitrary reference time by a known method. The abnormality control process and the reference time rewriting process performed by this control unit will be described later.

  The memory 73 is a storage unit that records information necessary for various controls of the optical line termination device 70, and is configured in the same manner as the control unit of the first embodiment except for the points described below. Here, the memory 73 is roughly configured to include a reference time storage unit 73a, and the reference time storage unit 73a is a reference time storage unit that stores a reference time, and is used in an abnormality control process to be described later. A reference time used as a presence / absence determination index is stored.

(processing)
Next, the processing of the optical line termination device 70 configured as described above will be described. The processing performed by the optical line termination device 70 includes an abnormality control process for controlling the optical line termination device 70 when it is determined that there is an abnormality in the optical line termination device 70 and the like, and is stored in the reference time storage unit 73 a of the memory 73. This is classified into reference time rewriting processing for rewriting the reference time by remote control.

(Processing-Abnormal control processing)
First, the abnormality control process according to the present embodiment will be described. First, an outline of the abnormality control process will be described. First, in the reference time storage unit 73a, an arbitrary reference is set as a value larger than at least the continuous transmission time of the optical signal (that is, the time allocated by the center modem) when the optical line termination device 70 is operating normally. The time is set. Therefore, when the optical line terminator 70 or the like is operating normally, the continuous transmission time does not exceed the reference time, but when the optical line terminator 70 or the like is not operating normally, There is a possibility that the line terminating device 70 continues to transmit an optical signal to the center device 60 for a certain time or more. In such a case, the continuous transmission time exceeds the reference time. The abnormality control process in the present embodiment is a process for determining and controlling the presence or absence of such a failure in the optical line terminating device 70.

  Next, specific contents of the abnormality control process will be described. First, the optical transmission time measuring unit 71 starts measuring the continuous transmission time when detecting the output of the optical signal, and transmits the measured continuous transmission time to the control unit. In response to this, the abnormality determination unit 72 a of the control unit compares the continuous transmission time transmitted from the optical transmission time measurement unit 71 with the reference time stored in the memory 73. When the continuous transmission time exceeds the reference time, the abnormality determination unit 72a determines that there is an abnormality in the optical line termination device 70 and the like, and the control signal transmission unit 72b controls the open / close switch 49 to open. Send a signal. Then, as in the first embodiment, the open / close switch 49 that has received the open control signal is in an open state, whereby the optical signal output from the optical line terminating device 70 to the center device 60 can be cut off.

  On the other hand, when the continuous transmission time does not exceed the reference time, the abnormality determination unit 72a determines that there is no abnormality in the optical line termination device 70 and the like, and the control signal transmission unit 72b controls the open / close switch 49 to be closed. Send a signal. As in the first embodiment, the open / close switch 49 that has received the close control signal is in a closed state, whereby the optical signal output from the optical line terminating device 70 to the center device 60 can be cut off.

(Processing-reference time rewriting process)
Next, the reference time rewriting process will be described. This reference time rewriting process is a process of rewriting the reference time stored in the reference time storage unit 73a of the optical line terminator 70 designated by the user among the plurality of optical line terminators 70 connected to the center apparatus 60. is there. The method for specifying the optical line terminator 70 to be processed is arbitrary. For example, when an ID is set in advance for each optical line terminator 70 and this ID is registered in the center device 60, In this case, it is possible to designate the optical line terminating device 70 for rewriting the reference time by using this ID.

  Specifically, first, the user operates the remote control unit 61 of the center device 60 to register the ID of the optical network unit 70 for which the reference time is desired to be rewritten and the desired reference time. The ID of the optical line termination device 70 is stored in advance in the memory 15 of the center device 60, for example. In response to this registration, the control unit 18 of the center device 60 transmits a signal including information related to the ID and a desired reference time via the transmission / reception unit 17. The signal transmitted in this way is transmitted to the control unit 72 of the optical line termination device 70 via the transmission system 20 and the optical transmission / reception terminal 41 of the optical line termination device 70. Then, the control unit 72 extracts the ID included in this signal, and determines whether or not this ID matches the ID preset in the optical line terminating device 70. If it is determined that they do not coincide with each other, it is determined that the signal is not transmitted to the optical network unit 70, and the received signal is ignored. On the other hand, when it is determined that they match, it is determined that the signal is sent to the optical line terminating device 70, and the reference time rewriting unit 72c of the control unit 72 of the optical line terminating device 70 The reference time stored in the reference time storage unit 73a of the optical line terminating device 70 is rewritten with reference to the included reference time information. In this way, the reference time stored in the reference time storage unit 73a can be rewritten even at a remote location of the optical line terminating device 70.

(effect)
As described above, according to the optical line termination device 70 described in the present embodiment, when the optical line termination device 70 continues to transmit optical signals to the center device 60 continuously for a predetermined time or longer, Since it is determined that an abnormality has occurred in the optical line terminator 70 and the optical signal output of the optical line terminator 70 can be cut off, the optical signal is continuously transmitted to the center device 60 for a predetermined time or more. It is possible to easily cut off the signal output of the optical line termination device 70 that is causing a communication failure due to a failure to continue transmitting signals.

  In addition, since the reference time stored in the optical line termination device 70 can be remotely controlled by the remote control unit 61 installed in the center device 60, it is easily set to the reference time suitable for the communication state by remote operation. It is possible to change.

[III] Modifications to Each Embodiment While each embodiment according to the present invention has been described above, the specific configuration and means of the present invention are the same as the technical idea of each invention described in the claims. Modifications and improvements can be arbitrarily made within the range. Hereinafter, such a modification will be described.

(About problems to be solved and effects of the invention)
First, the problems to be solved by the invention and the effects of the invention are not limited to the above-described contents, and the present invention solves the problems not described above or has the effects not described above. There are also cases where only some of the described problems are solved or only some of the described effects are achieved.

(About distribution and integration)
Each electrical component described above is functionally conceptual and does not necessarily need to be physically configured as illustrated. In other words, the specific form of distribution and integration of each part is not limited to the one shown in the figure, and all or a part thereof may be functionally or physically distributed or integrated in arbitrary units according to various loads or usage conditions. Can be configured.

(About optical reception level measurement unit)
In the above-described embodiment, it has been described that the abnormality control process is performed according to the optical signal level of the broadcast signal transmitted from the broadcast center. For example, the abnormality control process is performed according to the carrier level of a remote control device (not shown). You may go. Specifically, a carrier level measurement unit is provided on the path of the optical line termination device 40 instead of or in addition to the optical reception level measurement unit 47. The carrier level measuring unit is a carrier level measuring unit that measures the carrier level of a signal transmitted from a remote control device for remotely operating the optical line terminating device 40. Then, the abnormality determination unit 48a determines that there is an abnormality when the carrier level measurement unit cannot detect the carrier level, and determines that there is no abnormality when the carrier level can be detected. . In addition, about the process which the control part 48 performs after determining the presence or absence of abnormality, since it is possible to employ | adopt the process similar to this Embodiment, the detailed description is abbreviate | omitted.

  The reason why it is possible to determine whether there is an abnormality with such a configuration will be described below. That is, when the remote control device or the like is operating normally, the optical line terminators 40 and 70 are used for the carrier level of the signal transmitted from the remote control device regardless of whether or not the signal is transmitted from the remote control device. However, even when the receiving system of the optical line termination devices 40 and 70 fails, it is possible that even this carrier level cannot be detected. Therefore, by measuring the carrier level of the signal transmitted from the remote control device by the carrier level measurement unit, if this carrier level is not detected, it can be determined that there is an abnormality in the optical line termination devices 40, 70, etc. Is possible.

  According to such optical line terminators 40 and 70, when the carrier level of the signal transmitted from the remote control device cannot be detected, an abnormality has occurred in the optical line terminators 40 and 70. Since the optical signal output of the optical line terminators 40 and 70 can be cut off, the optical line terminators 40 and 70 that are highly likely to cause a communication failure due to a failure in the receiving system or the like. This signal output can be easily cut off.

(About optical transmission blocking means)
In this embodiment, the optical transmission blocking means is formed as the open / close switch 49. However, the optical transmission blocking means has a configuration capable of blocking the transmission of the optical signal from the optical line terminators 40 and 70. For example, the transmission of the optical signal of the optical line terminators 40 and 70 may be blocked by blocking the gate of the LD 45.

(About abnormal control processing)
In the present embodiment, the abnormality control process has been described on the assumption that an abnormality has occurred in the optical line termination devices 40 and 70. However, the abnormality control process is a device connected to the downstream side of the optical line termination devices 40 and 70. Even when an abnormality occurs in a device that can affect the transmission state of the upstream signal by the optical line termination devices 40 and 70, the abnormality control process can be performed in the same manner. For example, the receiver 30 is a device connected to the downstream side of the optical line terminators 40 and 70 and can affect the transmission state of the upstream signal by the optical line terminators 40 and 70. It can be considered that the optical transmission line termination devices 40 and 70 continue to transmit optical signals beyond the reference time due to a failure of 30 transmission systems. However, even in this case, it is possible to stop the output of the optical signal from the optical line terminators 40 and 70 by performing the abnormality control process in the same manner, and it is possible to eliminate the communication trouble of the notification broadcasting system 1. is there.

1, 2 Announcement broadcasting system 10, 60 Center device 11 Operation unit 12, 50 Display unit 13 Microphone 14 BGM source 15, 51, 73 Memory 16 Date / time circuit 17 Transmission / reception unit 18, 48, 72 Control unit 20 Transmission system 21 Head end 22 Optical transmission line 23 Optical amplifier 24 Optical distribution amplifier 25 Optical distributor 30 Receiver 40, 70 Optical line termination device 41 Optical transmission / reception terminal 42 PD
43 Electric transmission terminal 44 Electric reception terminal 45 LD
46 Optical mixer 47 Optical reception level measurement unit 48a, 72a Abnormality determination unit 48b, 72b Control signal transmission unit 49 Open / close switch 51a Reference level storage unit 61 Remote control unit 71 Optical transmission time measurement unit 72c Reference time rewriting unit 73a Reference time storage Part

Claims (6)

An optical line termination device that performs bidirectional communication of optical signals with a broadcasting center,
An optical signal receiving means for receiving an optical signal;
Photoelectric conversion means for converting an optical signal received by the optical signal receiving means into an electrical signal;
An electrical signal transmitting means for transmitting an electrical signal converted by the photoelectric conversion means;
Electrical signal receiving means for receiving electrical signals;
Electro-optic conversion means for converting the electrical signal received by the electrical signal receiving means into an optical signal;
An optical signal transmission means for transmitting the optical signal converted by the electro-optic conversion means;
Abnormality determining means for determining whether or not there is an abnormality in the optical line termination device or a device connected to the downstream side of the optical line termination device, which may affect the transmission state of the upstream signal by the optical line termination device When,
Optical transmission blocking means for blocking transmission of an optical signal by the optical signal transmission means when it is determined that there is an abnormality in the abnormality determination means,
Optical line termination equipment. Optical signal level measuring means for measuring the level of the optical signal received by the optical signal receiving means,
The abnormality determining means determines that there is an abnormality when the level of the optical signal received by the optical signal level measuring means is below a reference level,
The optical line terminator according to claim 1. Optical transmission time measuring means for measuring the continuous transmission time of the optical signal by the optical signal transmitting means,
The abnormality determining means determines that there is an abnormality when the continuous transmission time of the optical signal measured by the optical transmission time measuring means exceeds a reference time,
The optical line termination device according to claim 1 or 2. Reference time storage means for storing the reference time;
Remote control means installed in the broadcast center, wherein the remote control means transmits a remote control signal for controlling the reference time;
When it is determined that the optical signal receiving means has received the remote control signal transmitted from the remote control means, the reference time stored in the reference time storage means is controlled based on the remote control signal. A reference time control means for
The optical line termination device according to claim 3. Carrier level measuring means for measuring the carrier level of a signal transmitted from a remote control device for remotely operating the optical line termination device,
The abnormality determination means determines that there is an abnormality when the carrier level measurement means cannot detect the carrier level.
The optical line termination device according to any one of claims 1 to 4. When it is determined that there is an abnormality in the abnormality determination unit, or when the transmission of the optical signal is blocked in the optical transmission blocking unit, a display unit that displays that effect is provided.
The optical line termination device according to any one of claims 1 to 5.

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