JP2009296492A - Notice broadcast outputting method of optical terminal device and optical terminal device of optical transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To output a notice broadcast also to a subscriber who stops outputting an RF signal both in power failure of a commercial light source and RF signal output stoppage, and to make a notice broadcast terminal device readily movable. <P>SOLUTION: An optical signal is photoelectrically converted to take out the RF signal. The RF signal and a notice broadcast signal included in the RF signal are transmitted via respective RF path and notice path. An output end is used in common by the RF and notice paths. The notice broadcast signal is transmitted via the RF path and output from the common output end, when the optical terminal device is in a commercial power source conductive/RF signal output state, transmitted via the notice path and output from the common output end, when the optical terminal device is in a commercial power source conductive/RF signal output stopped state and transmitted via the notice path and output from the common output end, when the optical terminal device is in a commercial power source stopped state. In this case, the common output end is automatically switched and connected to the RF or notice path to output the notice broadcast transmitted via the RF or notice path from the common output end. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a notification broadcast output method for an optical terminal device of an optical transmission system such as CATV or CCTV, and an optical terminal device used therefor.

  In recent years, an information transmission system using an optical transmission facility has become widespread, and an FTTH (fiber-to-the-home) CATV system is one example. An information transmission system using an optical transmission facility provides a multi-channel service for television signals, and there is an announcement broadcasting system that quickly transmits emergency information such as earthquakes and disasters as part of the service. The notification broadcast system is configured such that a notification broadcast signal can be received by a dedicated notification broadcast reception terminal device (notification broadcast terminal device). Announcement broadcasting is usually operated with an FM signal of 70 to 90 MHz. Since notification broadcasting is assumed to be operated in an emergency due to the nature of transmitting emergency information, the notification broadcasting terminal device has specifications that can cope with a power failure of the commercial power supply.

  As shown in FIGS. 6 (a) and 6 (b), the notification broadcasting terminal device is usually installed at a downstream position (in the system subscriber's home B) of the optical terminal device A of the optical transmission system. The optical terminal device A converts and outputs an input optical signal into a high-frequency electrical signal (RF signal), and the RF signal includes a television signal and a notification broadcast signal. Since the optical terminal device A generally operates with a commercial power supply, it cannot send a broadcast notification signal to the notification broadcast terminal device C unless it operates even during a commercial power failure. For this reason, the optical terminal device A is required to be able to cope with a power failure of the commercial power supply.

  In order to output a notification broadcast signal in the event of a commercial power failure, conventionally, a backup power supply is prepared (for example, see Patent Document 1), or a reception terminal for FM notification broadcast is prepared separately from the television signal. Products with receiving terminals are also sold.

JP 2006-174221 A

  The method of using a battery as a backup power supply as one of the countermeasures for commercial power supply interruptions requires frequent battery replacement because the battery life is short, resulting in high maintenance costs. In order to solve this, it is possible to prepare for a power outage while charging using a secondary battery, but even a secondary battery has a long life of about 2 to 3 years, and charging control is costly Therefore, it is not realistic as an optical terminal device with intense price competition. Therefore, in Patent Document 1, the backup power source is a capacitor. Capacitors are not as good as secondary batteries, but cannot solve the problems of cost and life. In any case, when the operation is performed by the backup power supply, the time that can be operated by the backup power supply becomes a problem. Eventually, the backup power supply will be discharged in a matter of hours, and there will remain concerns if the power outage lasts for a long time.

  For businesses that provide multi-channel TV signal services using optical transmission facilities, it is desirable to be able to collect usage fees smoothly from subscribers to the service, but there are some subscribers whose payments are delayed. It is a problem. Therefore, a transmission system is operated so that a service is not provided to a subscriber who has not paid a usage fee. This system controls the output of the RF signal of the optical terminal device to stop, and the subscriber's house under this control cannot watch TV. However, for humanitarian considerations, the announcement broadcast signal needs to be distributed to subscribers who are under RF signal output stop control.

  An optical terminal device is generally installed outdoors such as an eaves of a subscriber's house, and an RF signal is drawn into the subscriber's house by a coaxial cable. As shown in FIG. 6B, there is an example in which an optical terminal device in which an announcement broadcast signal output terminal and a television signal output terminal are separated is commercialized. In this product, separate coaxial cables are connected to each terminal, so it is necessary to construct two coaxial cables. Wiring is complicated, so it is shunned from the construction aspect and the optical terminal device is damaged. Tends to be shunned from the subscriber's home. In addition, since the announcement broadcast signal is output only from the coaxial cable connected to the output terminal for the announcement broadcast signal, a new coaxial cable is wired to move the announcement broadcast terminal once installed to another location. There is a problem that it is not possible to move easily because it requires reworking. This will inconvenience the subscriber.

  The present invention notifies a peripheral circuit of an optical / electrical conversion element that converts an input optical signal into a high-frequency electrical signal (RF signal) even when the commercial power supply is interrupted (state) or when the RF signal output is stopped (state). The present invention relates to an announcement broadcast output method for an optical terminal device capable of outputting a broadcast signal and an optical terminal device used therefor.

According to the optical terminal device announcement broadcast output method of the present invention, the optical signal transmitted in the optical transmission system is optically / electrically converted in the optical terminal device of the optical transmission system to extract the RF signal as described in claim 1, In the notification broadcast output method for outputting the RF signal and the notification broadcast signal included therein from the output terminal of the optical terminal device, the RF signal output terminal and the notification broadcast signal output terminal are shared,
An RF signal and a notification broadcast signal are transmitted through an RF path and a notification path. The notification broadcast signal is transmitted from the common output terminal by transmitting the RF path when the optical terminal device is in a commercial power supply energized / RF signal output state. When the apparatus is in a commercial power supply energization / RF signal output stop state, the notification path is transmitted and output from the shared output terminal. When the apparatus is in a commercial power supply stop state, the notification path is transmitted and output from the shared output terminal. It is characterized by this. In this case, as described in claim 2, in the notification broadcast output method, the shared output end of the optical terminal device is automatically switched and connected to the RF path and the notification path according to the state, and the RF path or the notification path is connected. Can also be output from the shared output terminal.

  The optical terminal device of the optical transmission system of the present invention, as claimed in claim 3, optically / electrically converts an optical signal transmitted in the optical transmission system to extract an RF signal, and the RF signal and notification broadcast included therein In an optical terminal device that outputs a signal from an output end, an RF signal output end and a notification broadcast signal output end are used as a common output end, an optical / electrical conversion element, an RF path for transmitting the RF signal and the notification broadcast signal, and a notification path, A path switching switch for selectively switching and connecting the common output end to the RF path and the notification path, and a control circuit for controlling switching of the path switching switch. The control circuit is connected to the commercial power supply / RF signal output. Connect to the RF path in the state, connect to the notification path in the state of commercial power supply energization and RF signal output stop, and connect to the notification path in the state of commercial power supply stop. Announcement broadcast signal is obtained by a selectable switching control so as to be outputted from the common output terminal.

  According to the optical terminal device of the optical transmission system of the present invention, as described in claim 4, in the optical terminal device, on the RF signal extraction side of the optical / electrical conversion element, a notification route / ground that can be selectively switched between the notification route and the ground is provided. An earth changeover switch can be provided. In this case, as described in claim 5, in the optical terminal device of the optical transmission system, a power / ground switch that can be selectively switched between power and ground can be provided on the RF signal extraction end side of the optical / electrical conversion element. . According to a sixth aspect of the present invention, a coil can be provided between the RF signal extraction end side of the optical / electrical conversion element and the power / ground switch.

  In the notification broadcast output method of the present invention, the common output end of the RF signal and the notification broadcast signal is set to a commercial power supply energization / RF signal output stop state, a commercial power supply energization / RF signal output stop state, and a commercial power supply power failure state. Accordingly, since the selection is switched between the RF path and the notification path, the notification broadcast can be output from the shared output terminal even when the commercial power supply is interrupted or the RF signal output is stopped.

The optical terminal device of the present invention has the following effects.
1. The RF signal output end and the notification broadcast signal output end are shared, and the common output end is in a commercial power supply energization / RF signal output stop state, a commercial power supply energization / RF signal output stop state, or a commercial power supply power outage state. Accordingly, a control circuit for selectively switching the route selection switch between the RF route and the notification route is provided. By appropriately controlling the route selection switch according to these states, the RF signal can be obtained even in a commercial power failure state. Even when the output is stopped, the notification broadcast signal can be output from the shared output terminal.
2. Since it is possible to output a notification broadcast signal even when there is a commercial power failure without installing a backup power supply, there is no trouble in maintaining the backup power supply.
3. Since the broadcast broadcast signal can be output even in the RF signal output stop control state, only the broadcast broadcast signal can be provided to subscribers who are unable to view the television due to reasons such as unpaid usage fees. This is also preferable from the humanitarian perspective.
4). Since the broadcast signal and television signal output terminals are shared, it is easy to install a coaxial cable downstream from the optical terminal equipment, and any broadcast terminal can be connected to any wall terminal distributed in the subscriber's house. You can listen to the announcement broadcast. FIG. 1 is an example of an image diagram. A television receiver (TV) 4 is arranged in each of four rooms, and one of the rooms distributes an RF signal and is connected to the TV and the notification broadcasting terminal device 5. . Even if this notification broadcast terminal device is replaced with a television receiver in another room, the notification broadcast signal can be received, so that the degree of freedom of the installation location of the notification broadcast terminal device is increased.

(Embodiment 1: Configuration of optical terminal apparatus of FIGS. 1 to 4)
An embodiment of an optical terminal device of the present invention will be described with reference to FIGS. The information transmission system in FIG. 1 is a case where the optical terminal device 3 is a V-ONU, and a high-frequency signal (RF signal) transmitted through the optical transmission line 1 is an optical / electrical conversion element (for example, photo) of the optical terminal device 3. A diode (PD) (FIGS. 2 to 4) is converted into an electrical signal, and an RF signal (television signal) is taken out and drawn into the subscriber home 2 via the coaxial cable 6 as shown in FIG. Are received by the respective TV receivers 4. When an abnormality occurs, a notification broadcast signal included in the RF signal is drawn into the subscriber's house 2 through the coaxial cable 6 and a notification broadcast is output from the notification broadcast terminal device 5.

  2 to 4 have the same configuration, except that FIG. 2 shows the state of commercial power supply / RF signal output, and FIG. 3 shows the state of commercial power supply / RF signal output. The stop state, FIG. 4 shows a commercial power failure state.

  2 to 4 show a case where an RF signal including an announcement broadcast is taken out from the cathode terminal of the photodiode PD and an RF signal including the announcement broadcast is taken out from the anode terminal. In order to efficiently extract an RF signal from the photodiode PD at the time of a commercial power failure, it is necessary to connect the cathode terminal to GND at a high frequency. Therefore, in any of the optical terminal devices of FIGS. 2 to 4, a power supply / grounding switch SW <b> 1 is provided at the cathode terminal of the photodiode PD so as to be switched and connected to the power supply (Vcc) or the ground (GND). A high-frequency cut coil L is arranged between the power / ground switch SW1 and the cathode terminal.

  The optical terminal device 3 in FIGS. 2 to 4 is provided with a notification broadcast signal path (notification path) C1 at the cathode terminal of the photodiode PD, and the notification path C1 is switched and connected to ground (GND) and a low-pass filter (LPF). / Filter changeover switch SW2 is provided. An RF signal transmission path (RF path) C2 is provided at the anode terminal of the photodiode (PD), and an amplifier 1, an amplifier 2 and an amplifier 3 are provided in series on the RF path C2. The common output terminal 10 can be selectively switched and connected to the notification path C1 and the RF path C2 by a path switch SW3.

  2 to 4, the notification broadcast signal is taken out from the cathode terminal of the photodiode PD and the television signal is taken out from the anode terminal. However, the RF signal can be taken out from either the anode terminal or the cathode terminal. Therefore, the announcement broadcast signal and the RF signal can be taken out from the terminals opposite to those in FIGS.

  2 to 4 includes an RF control circuit 7 for switching and controlling the power switch SW4, a switching control circuit 8 for switching and controlling the power / earth switching switch SW1, the notification path / filter switching switch SW2, and the path switching switch SW3. Is also provided.

(Embodiment 2: Configuration of optical terminal device in FIG. 5)
The basic configuration of the optical terminal device of FIG. 5 is the same as that of the optical terminal device 3 of FIGS. 2 to 4 except that the RF signal taken out from the anode terminal of the photodiode PD is divided into two by the distributor 9. The other distribution signal is transmitted to the notification path C1, and the other distribution signal is transmitted to the RF path C2. 2 to 4, the notification path C1 is provided with the notification path / ground switch SW2, the RF path C2 is provided with the amplifier 1, the amplifier 2, and the amplifier 3 in series, and the shared output terminal 10 is switched. The switch SW3 can be selectively switched between the notification path C1 and the RF path C2.

(Embodiment 3: Another configuration of the optical terminal device of FIG. 5)
In FIG. 5, the RF signal is extracted from the anode terminal of the photodiode PD. However, the RF signal can also be extracted from the cathode terminal of the photodiode PD and can be divided into two.

(Embodiment 4)
Each of the switches SW1 to SW4 of the first to third embodiments may be a mechanical switch, a semiconductor switch, or the like as long as the function of the present invention can be realized.

(Description of operation of optical terminal device in FIG. 2)
FIG. 2 shows the case of commercial power supply energization / RF signal output state. Since the RF signal is being output, the power switch SW4 is connected, and Vcc is supplied to the control terminals of the switches SW1 and SW2, the control terminals 1 and 2 of the SW3, and the amplifier 3. Since the commercial power supply is energized, Vcc can be applied to the photodiode PD, and the switch SW1 is connected to the DC1 terminal and the COM terminal by the control from the control terminal.

  The RF signal output from the cathode of the photodiode PD is input to the notification path / filter switching switch SW2. The notification path / filter switching switch SW2 is connected to the COM1 terminal and the RF2 terminal under the control of the control terminal, and is grounded to the GND through the capacitor C. As a result, the cathode side of the photodiode PD is grounded in a high frequency manner. The RF signal output from the anode of the photodiode PD is amplified by the amplifiers 1, 2, and 3 and input to the above-described path changeover switch SW3. The path changeover switch SW3 is connected to the RF2 terminal and the COM1 terminal under the control of the control terminal 2, and the RF signal is output from the V-ONU shared output terminal OUT. Since this RF signal includes a notification broadcast signal and a television signal, both the notification broadcast and the multi-channel television service can be provided, and the notification broadcast terminal apparatus that receives the notification broadcasts the notification broadcast.

(Description of operation of optical terminal device in FIG. 3)
FIG. 3 shows a commercial power supply energization / RF signal output stop state. Since the RF signal output is stopped, the power switch SW4 is not connected, Vcc is not supplied to the control terminal of each switch SW1, SW2, SW3 and the amplifier 3, and the DC2 terminal and the COM1 terminal are connected to the switch SW1 by the control terminal. The As a result, as described in the operation of the optical terminal device in FIG. 2, it is possible to output an RF signal from the photodiode PD even when Vcc is not energized.

  The RF signal output from the anode of the photodiode PD is amplified by the amplifiers 1 and 2, but the amplifier 3 is not operating, so that no further signal is transmitted. The RF signal output from the cathode of the photodiode PD is input to the notification path / filter switching switch SW2. The switch SW2 is connected between the COM1 terminal and the RF1 terminal by a control terminal. The RF signal output from the RF1 terminal of the notification path / filter switching switch SW2 is input to the low-pass filter LPF and outputs only the notification broadcast signal. The announcement broadcast signal output from the LPF is input to the path switch SW3. The path changeover switch SW3 is controlled by the control terminals 1 and 2, the RF1 terminal and the COM1 terminal are connected, and the notification broadcast signal is output from the common output terminal 10.

(Description of operation of optical terminal device in FIG. 4)
FIG. 4 shows a commercial power failure state. Since the commercial power supply has failed, Vcc is 0V. Therefore, the voltage output from the power switch SW4 is naturally 0V, and DC is not supplied to the control terminals of the switches SW1 to SW3 and the amplifier 3. For this reason, the power / ground switch SW1 is controlled by the control terminal to connect the DC2 terminal and the COM1 terminal.

  The RF signal output from the anode of the photodiode PD is input to the amplifier 1, but the amplifiers 1, 2, and 3 are not operating and cannot be amplified. The RF signal output from the cathode of the photodiode PD is input to the switch SW2. The switch SW2 is connected to the COM1 terminal and the RF1 terminal under the control of the control terminal. The RF signal output from the RF1 terminal of the switch SW2 is input to the LPF, and only the notification broadcast signal passes and is output to the switch SW3. The switch SW3 is controlled by the control terminals 1 and 2, the RF1 terminal and the COM1 terminal are connected, and the notification broadcast signal is output from the common output terminal 10.

(Description of operation of optical terminal device in FIG. 5)
FIG. 5 shows the state of commercial power supply / RF signal output as in FIG. Since it is in the RF signal output state, the power switch SW4 is connected, and Vcc is supplied to the control terminals of the switches SW1, SW2, SW3 and the amplifiers 1, 2, 3. Since the commercial power supply is energized, Vcc can be applied (energized) to the photodiode PD, and the DC1 terminal and the COM terminal of the power / ground switch SW1 are connected by the control terminal.

  The RF signal output from the anode of the photodiode PD is divided into two by the distributor 9, and one RF signal is input to the switch SW2. The switch SW2 is connected between the COM1 terminal and the RF2 terminal by a control terminal, and is grounded to the GND through the capacitor C. The other RF signal is amplified by the amplifiers 1, 2, and 3 and input to the path selection switch SW3. The path selection switch SW3 is controlled by the control terminal 1 and the control terminal 2 so that the RF2 terminal and the COM1 terminal are connected, and the RF signal is output from the shared output terminal OUT. Since the RF signal includes a notification broadcast signal and a television signal, both the notification broadcast and the multi-channel television service can be provided to the subscriber, and the notification broadcast terminal apparatus that receives the notification broadcasts the notification broadcast.

    The present invention can be used not only for the CATV system but also for other optical transmission systems such as CCTV and other optical transmission systems.

Explanatory drawing which shows an example of the wiring of the optical terminal device of this invention, the notification broadcasting terminal device in a subscriber company house, and a television receiver. The block diagram of an example of the optical terminal device of this invention, and a commercial power supply application and RF signal output state. The block diagram of an example of the optical terminal device of this invention, and a commercial power supply application and RF signal output stop state. The block diagram which shows an example of the optical terminal device of this invention, and shows a commercial power supply stop state. The block diagram in the case where an example of the optical terminal device of the present invention is shown and the RF signal is divided into two, in the commercial power supply / RF signal output state. (A) is explanatory drawing of the conventional optical transmission system (when the output of an optical terminal device is two), (b) is explanatory drawing of the optical terminal device of (a), and a subscriber company house part.

Explanation of symbols

1 Optical transmission line 2 Subscriber's home 3 Optical terminal equipment (V-ONU)
4 TV receiver 5 Notification broadcast terminal device 6 Coaxial cable 7 RF control circuit 8 Switching control circuit 9 Distributor 10 Shared output terminal Vcc Power supply GND Ground PD Photodiode LPF Low pass filter L Coil C1 Notification broadcast signal path (notification path)
C2 RF signal transmission path (RF path)
SW1 Power / ground switch SW2 Notification path / filter switch SW3 Path switch SW4 Power switch

Claims (6)

An optical signal transmitted in the optical transmission system is optically / electrically converted in an optical terminal device of the optical transmission system to extract an RF signal, and the RF signal and an announcement broadcast signal included therein are output from the output terminal of the optical terminal device. In the notification broadcast output method,
The RF signal output terminal and the notification broadcast signal output terminal are shared,
Transmit RF signal and announcement broadcast signal via RF path and announcement path,
When the optical terminal device is in the commercial power supply energized / RF signal output state, the announcement broadcast signal is transmitted through the RF path and output from the shared output terminal, and when the optical terminal device is in the commercial power supply energized / RF signal output stopped state, Is transmitted from the shared output terminal, and when the optical terminal is in a commercial power supply stop state, a notification path is transmitted and output from the shared output terminal.
An announcement broadcast output method for an optical terminal device.   2. The notification broadcast output method of an optical terminal device according to claim 1, wherein the shared output terminal of the optical terminal device is automatically switched and connected to the RF path and the notification path according to the state, and the RF path or the notification path is transmitted. An announcement broadcast output method for an optical terminal device, wherein the announcement broadcast is output from a shared output terminal. In an optical terminal device that optically / electrically converts an optical signal transmitted in an optical transmission system, extracts an RF signal, and outputs the RF signal and an announcement broadcast signal included therein from an output end,
The RF signal output terminal and the notification broadcast signal output terminal are used as the common output terminal.
An optical / electrical conversion element;
An RF path and an announcement path for transmitting the RF signal and the announcement broadcast signal;
A path switch for selectively switching and connecting the common output terminal to the RF path and the notification path;
A control circuit that controls the switching of the path switch is provided.
The control circuit connects the path changeover switch to the RF path in the state of commercial power supply energization / RF signal output, connects to the notification path in the state of commercial power supply energization / RF signal output stop, and It is possible to select and control switching so that the notification broadcast signal is output from the shared output terminal in any state.
An optical terminal device for an optical transmission system.   4. An optical terminal device for an optical transmission system according to claim 3, wherein an optical signal / electrical conversion element is provided with a notification path / ground switch that can be selectively switched between a notification path and a ground on the RF signal extraction side. Optical terminal device for transmission system.   5. The optical terminal device of the optical transmission system according to claim 3 or 4, further comprising a power / ground switch that can be selectively switched between power and ground on the RF signal extraction end side of the optical / electrical conversion element. An optical terminal device for an optical transmission system.   6. The optical terminal of an optical transmission system according to claim 5, wherein a coil is provided between the RF signal extraction end side of the optical / electrical conversion element and the power / ground switch. apparatus.

Images