JP4083764B2 - Notification broadcasting system - Google Patents

Description

  The present invention relates to a notification broadcasting system using a network of optical fiber cable television, and more particularly to measures for reducing the power supply of an optical receiver on the subscriber side.

  In recent years, as known from Patent Document 1 and Patent Document 2, a system that performs broadcast broadcasting of various information using a cable television network or the like in local governments has attracted attention.

  For example, in an optical fiber cable television network, as shown in FIG. 4, in a network center transmission facility 100, an audio information signal is converted into a television video signal (for example, 90 to 870 MHz) wavelength-multiplexed by an output mixer 170. (For example, 70 to 90 MHz) is mixed to generate a wide-band television electric signal (70 to 870 MHz). Then, the optical signal is converted into an optical transmission signal of a predetermined wavelength band (for example, 1310 nm band, 1550 nm band) by the optical transmitter 180, and then light in a long distance section constructed by a single mode optical fiber cable. It is sent to the transmission line facility 300.

  In the subscriber facility 400, the optical transmission signal transmitted via the optical transmission line facility 300 is received by the optical receiver 410, and the optical receiver 410 converts it into an electrical signal for TV (RF signal). And output. The output television electrical signal is input to the television receiver 430 via the set top box 420. At this time, the optical receiver 410 is supplied with power by the AC power environment 440 as in the case of the set top box 420 and the television receiver 430.

In the notification broadcast performed using such a network, the electric signal for television output from the optical receiver 410 is distributed in the distributor 600, and the notification broadcast such as FM radio is performed from the distributed electric signal for television. This is performed by extracting a voice information signal by the terminal 460.
JP 2002-368807 A (5th page, FIG. 1) Japanese Patent Laying-Open No. 2005-184700 (pages 5-7, FIG. 2)

  However, in the conventional case, the optical receiver 410 of the subscriber facility 400 does not operate in a power outage state, and thus there is a problem that it is not possible to receive a notification broadcast service in an emergency such as a disaster.

  For this, it is conceivable to install a battery for supplying power to the optical receiver 410 on the subscriber facility 400 side, but the battery needs to be replaced every two to three years. Therefore, there is a drawback that the cost is excessive.

  The present invention has been made in view of such various points, and its main purpose is to operate properly even when the optical receiver of the subscriber equipment is unpowered in a notification broadcasting system using a network of optical fiber cable television. Thus, the audio information signal can be appropriately output.

  In order to achieve the above object, the present invention focuses on the fact that the optical transmission signal has energy, branches the audio information signal before being mixed in the network center transmission facility, and only the audio information signal is Separately, an optical transmission signal is converted and transmitted, and the subscriber equipment receives an optical transmission signal only of the voice information signal, and adds an optical receiver that converts the energy of the optical transmission signal to operate itself. did.

  Specifically, the present invention includes a mixer that mixes a television video signal and an audio information signal with each other and outputs a television electrical signal, and converts the television electrical signal output from the mixer into an optical transmission signal. Network center transmission equipment having an optical transmitter for conversion and output, optical transmission line equipment for transmitting optical transmission signals sent from the network center transmission equipment, and light transmitted via the optical transmission line equipment An announcement broadcasting system having an optical receiver that receives a transmission signal, converts it into an electrical signal for television and outputs it, and a subscriber equipment having an announcement broadcasting terminal for performing announcement broadcasting based on the audio information signal. Is assumed.

  And in the said network center transmission equipment, after making said optical transmitter into a 1st optical transmitter, this network center transmission equipment is a distributor which branches the audio | voice information signal input into the said mixer. And a second optical transmitter that converts the audio information signal branched by the distributor into an optical transmission signal and outputs the optical transmission signal.

  The optical transmission line equipment is configured to transmit the optical transmission signal output from the first optical transmitter and the optical transmission signal output from the second optical transmitter. And

  Further, in the subscriber facility, the optical receiver is the first optical receiver, and the subscriber facility transmits the optical transmission transmitted from the second optical transmitter of the network center transmission facility. Assume that a second optical receiver for receiving a signal is included. At this time, the second optical receiver includes a photoelectric conversion unit that converts an optical transmission signal received by the second optical receiver into electric energy, and the electric energy obtained by the photoelectric conversion unit is used. It shall be comprised so that it may operate | move using.

  According to the present invention, in an announcement broadcasting system using a network of an optical fiber cable television, an audio information signal before being mixed with a television video signal is branched at a network center transmission facility, and an optical transmission signal is transmitted. The facility can output an electrical signal at a voltage level that can be received by the notification broadcasting terminal by converting the optical transmission signal into electrical energy. Can be secured.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 shows the overall configuration of a notification broadcasting system according to Embodiment 1 of the present invention, and this notification broadcasting system is constructed using a cable television network using optical fiber cables.

  This announcement broadcasting system is an optical transmission signal for television images that is a mixture of television image signals (terrestrial digital television signals, BS signals, CS signals, etc.) and audio information signals (FM radio broadcasts, announcement broadcasts, etc.). A network center transmission facility 10 for transmitting, and an optical transmission line facility 30 for carrying an optical transmission signal transmitted from the network center transmission facility 10, each of which is composed of a one-core or two-core optical fiber cable. It includes a plurality of subscriber facilities 40 that receive optical transmission signals transmitted via the transmission line facility 30 and perform various television broadcasts and radio broadcasts. In FIG. 1, only one subscriber facility 40 is shown.

  The network center transmission facility 10 described above is a pilot signal generator 11, a 64QAM modulator 12, an OFDM signal processor 13, an analog signal processor 14, an NTSC modulator 15, and the like. Has a modulator. The frequency band of this television video signal is, for example, 90 to 870 MHz. In addition, it has an FM communication modulator 16 that modulates a voice information signal input by reception by an antenna or the like. The frequency band of the audio information signal is, for example, 70 to 90 MHz.

  Further, on the output side of the modulators 11 to 16, an output mixer 17 is provided for mixing the output signals of the modulators 11 to 16 and outputting a television electric signal. On the output side, there is provided a first optical transmitter 18 that converts the electrical signal for television output from the output mixer 17 into an optical transmission signal of a predetermined wavelength band (for example, 1550 nm band) and outputs the optical transmission signal. Yes. Further, on the output side of the first optical transmitter 18, an optical fiber amplifier 19 for amplifying the optical transmission signal output from the first optical transmitter 18, and the optical transmission signal output from the optical fiber amplifier 19 are provided. An optical splitter 20 that branches by a predetermined number is provided in order. The optical fiber amplifier 19 and the optical splitter 20 are arranged in series in a plurality of stages according to the required number of distributions.

  On the other hand, the subscriber equipment 40 is provided with a first optical receiver 41 that receives an optical transmission signal transmitted via the optical transmission line equipment 30 and reconverts it into an electric signal for television. . The output side of the first optical receiver 41 is connected to a set top box 42 to which an electrical signal for television output from the first optical receiver 41 is input. The first optical receiver 41 is connected via the set top box 42. The subscriber facility 40 has an AC power supply environment 44. The AC power supply environment 44 supplies power to the first optical receiver 41 via the AC power supply adapter 45, and is set. The top box 42 and the television receiver 43 are also supplied with power. Further, the subscriber facility 40 is provided with a notification broadcasting terminal 46 such as an FM radio that performs notification broadcasting. This notification broadcasting terminal 46 has a built-in dry battery or storage battery as a power source, and operates with the electrical energy of the built-in power source when an audio information electrical signal of an appropriate voltage level (for example, 60 ± 10 dBμV) is input. It is supposed to be.

  In the present embodiment, the network center transmission facility 10 includes the two distributors 21 that branch the voice information signal input to the output mixer 17 and the voice information signals that are branched by the two distributors 21. A second optical transmitter 22 that converts and outputs an optical transmission signal in a predetermined wavelength band (for example, 1310 nm band) different from that of the first optical transmitter 18. A 16 distributor 23 that distributes the audio information signal input from the 2 distributor 21 into 16 signals is provided on the branched output side of the 2 distributor 21. On the output side of the 16 distributor 23, an RF amplifier 24 that amplifies the audio information signal output from the 16 distributor 23, and 16 audio information signals amplified by the RF amplifier 24 are respectively converted into 32 signals. A 32 distributor 25 for distribution is provided in order, and an audio information signal output from the 32 distributor 25 is input to the second optical transmitter 22. The 16 distributors 23 and the RF amplifiers 24 are provided in a plurality of stages according to the required number of distributions.

  An optical splitter 26 that distributes the optical transmission signal output from the second optical transmitter 22 to a predetermined number of optical transmission signals is provided on the output side of the second optical transmitter 22. The optical transmission signal output from 26 is sent to the optical transmission line facility 30. In the present embodiment, the optical transmission signal on the first optical transmitter 18 side and the optical transmission signal on the second optical transmitter 22 side have different wavelength bands. Even when the optical fiber cable has one core, it can be sent out.

  On the other hand, the subscriber facility 40 is provided with a second optical receiver 50 that receives an optical transmission signal transmitted from the second optical transmitter 22 of the network center transmission facility 10. As shown in FIG. 2, the second optical receiver 50 includes a light receiving unit 51 that converts an optical transmission signal received by the second optical receiver 50 into an audio information electrical signal (RF signal), and the light receiving unit 51. A photoelectric conversion unit 52 that converts an optical transmission signal received by the light receiving unit 51 into electrical energy, and an audio information electrical signal output from the signal light receiving unit 51 is transmitted to the notification broadcasting terminal 46. And an RF signal transformer 53 for transforming to an input voltage level and outputting. The RF signal transformer 53 is operated with electric energy obtained by the photoelectric converter 52. Further, the notification broadcast terminal 46 is directly input with the output of the second optical receiver 50 without using a distributor as in the conventional case.

  In the notification broadcasting system configured as described above, the optical transmission signal for television transmitted from the first optical transmitter 18 of the network center transmission facility 10 is received by the first optical receiver 41 of the subscriber facility 40. Then, it is input to the television receiver 43 via the set top box 42. On the other hand, the optical transmission signal for voice information transmitted from the second optical transmitter 22 of the network center transmission facility 10 is received by the second optical receiver 50 of the subscriber facility 40, and is sent to the notification broadcasting terminal 46. The output signal of the two-optical receiver 50 is directly input. At that time, the second optical receiver 50 converts the optical transmission signal received by the second optical receiver 50 into electric energy by the photoelectric conversion unit 52 and operates by itself with the electric energy. The optical transmission signal is converted into an audio information electrical signal and output without receiving an external power source such as a battery. In addition, when the RF output level of the second optical receiver 50 is lower than the appropriate level, the modulation degree of the second optical transmitter 22 of the network center transmission facility 10 is adjusted (for example, 20%). The distortion characteristics of the second optical transmitter 22 can be improved, and the RF output signal of the second optical receiver 50 can be obtained at an appropriate level.

  Therefore, according to the present embodiment, the output mixer 17 that mixes the TV video signal and the audio information signal and outputs the TV electric signal is provided, and the TV electric signal output from the output mixer 17 is received. A network center transmission facility 10 having a first optical transmitter 18 that converts and outputs an optical transmission signal, an optical transmission line facility 30 that transmits an optical transmission signal transmitted from the network center transmission facility 10, and the optical transmission Notification broadcast terminal that has a first optical receiver 41 that receives an optical transmission signal transmitted via the line facility 30, converts it into an electrical signal for television, and outputs it, and performs an announcement broadcast based on an audio information signal In the notification broadcasting system including a plurality of subscriber facilities 40 having 46, the network center transmission facility 10 is connected to the output mixer 17. A second distributor 21 for branching a voice information signal to be input, and a second optical transmitter 22 for converting the voice information signal branched by the two distributor 21 into an optical transmission signal and outputting the optical transmission signal. The optical transmission signal output from the transmitter 18 and the optical transmission signal output from the second optical transmitter 22 are transmitted via the optical transmission line facility 30, while the network center is connected to each subscriber facility 40. A second optical receiver 50 that receives an optical transmission signal transmitted from the second optical transmitter 22 of the transmission facility 10 is provided, and the second optical receiver 50 is connected to the photoelectric converter 52 of the second optical receiver 50. Since it operates with electrical energy obtained by converting the optical transmission signal into energy, even if a power failure occurs in the event of a disaster, etc., it is appropriate for the notification broadcasting terminal 46 without relying on an external power source such as a battery. Voice information It is possible to output a signal.

(Embodiment 2)
FIG. 3 shows the overall configuration of the notification broadcasting system according to the second embodiment of the present invention, and this notification broadcasting system also uses a cable television network using an optical fiber cable, as in the first embodiment. It was built as a result. In addition, the same code | symbol is attached | subjected and shown to the same part as the case of Embodiment 1. FIG.

  In the present embodiment, the optical transmission line facility 30 is composed of a two-core optical fiber cable. In the network center transmission facility 10, the 16 distributor 23, the RF amplifier 24, and the 32 distributor 25 in the case of the first embodiment are omitted, and instead, the output side of the second optical transmitter 22 An optical fiber amplifier 27 that amplifies the optical transmission signal output from the second optical transmitter 22 is provided, and an output signal of the optical fiber amplifier 27 is input to the optical splitter 26. The second optical transmitter 22 converts the audio information electrical signal branched by the two distributors 21 into an optical transmission signal in the same wavelength band (1550 nm band in this example) as that of the first optical transmitter 18. Accordingly, the optical transmission line facility 30 is configured so that the optical transmission signal of the first optical transmitter 18 and the optical transmission signal of the second optical transmitter 22 pass through different core wires. It consists of a two-core optical fiber cable for transmission. Since other configurations are the same as those in the first embodiment, description thereof is omitted.

  Therefore, the present embodiment can achieve the same effects as those of the first embodiment.

  In the second embodiment, the case where the optical transmission line facility 30 is made of a two-core optical fiber cable is described. However, the optical transmission line facility 30 is made of a one-core optical fiber cable. In some cases, by additionally providing a WDM filter or the like, it is possible to prevent the optical transmission signal for CATV and the optical transmission signal for audio signal including notification broadcast from interfering with each other.

It is a block diagram which shows the whole structure of the notification broadcasting system which concerns on Embodiment 1 of this invention. It is a block diagram which shows the structure of the 2nd optical receiver of subscriber equipment. It is the FIG. 1 equivalent figure which shows the whole structure of the notification broadcasting system which concerns on Embodiment 2 of this invention. FIG. 1 is a diagram corresponding to FIG. 1 illustrating an overall configuration of a conventional notification broadcasting system using a cable television network using an optical fiber cable.

Explanation of symbols

10 Network center transmission equipment 17 Output mixer (mixer)
18 First optical transmitter 21 2 Distributor (distributor)
22 2nd optical transmitter 30 Optical transmission line equipment 40 Subscriber equipment 41 1st optical receiver 50 2nd optical receiver 52 Photoelectric conversion part

Claims (1)

A mixer that mixes a television video signal and an audio information signal and outputs a television electrical signal; and an optical transmitter that converts the television electrical signal output from the mixer into an optical transmission signal and outputs the optical transmission signal. A network center transmission facility,
An optical transmission line facility for transmitting an optical transmission signal transmitted from the network center transmission facility;
An optical receiver that receives an optical transmission signal transmitted via the optical transmission line facility, converts the optical transmission signal into an electric signal for television, and outputs the electric signal;
A notification broadcasting system comprising subscriber equipment having a notification broadcasting terminal for performing notification broadcasting based on the audio information signal,
The optical transmitter of the network center transmission facility is a first optical transmitter,
The network center transmission facility includes: a distributor that branches an audio information signal input to the mixer; and a second optical transmitter that converts the audio information signal branched by the distributor into an optical transmission signal and outputs the optical transmission signal. And
The optical transmission line facility is configured to transmit an optical transmission signal output from the first optical transmitter and an optical transmission signal output from the second optical transmitter,
The optical receiver of the subscriber facility is a first optical receiver,
The subscriber facility includes a second optical receiver that receives an optical transmission signal transmitted from the second optical transmitter of the network center transmission facility,
The second optical receiver includes a photoelectric conversion unit that converts an optical transmission signal received by the second optical receiver into electrical energy, and operates with the electrical energy obtained by the photoelectric conversion unit. An announcement broadcasting system characterized by being configured.

Images