JP2005142773A - Transmission apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission apparatus capable of distributing a video image and a sound to a plurality of viewers at a low cost by using illumination lights of existing illumination facilities without newly preparing a base station for radio wave or an optical radio transmitter. <P>SOLUTION: A transmitting means 11 stores at least the content of any one of the video image or sound, and converts the content into the signal of a predetermined format in response to a command from the external and outputs the signal, and a transmission means 12 transmits this signal. In that case, a modulating means 13 modulates the transmitted signal, a light-emitting means 14 radiates the visible light modulated by the modulation means, and a reproducing terminal 15 receives the radiated visible light and demodulates a modulation signal superposed on the visible light to reproduce the video image and sound. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a transmission apparatus suitable for providing video and audio distribution services to passengers of moving bodies such as trains and airplanes.

As a conventional device of this type, a mobile vehicle such as a train is provided with a transceiver that receives information from a fixed station by a guided radio system or a radio wave system and retransmits the information wirelessly in the vehicle. There has been proposed an information providing system for a moving vehicle that includes a combination with a specific receiver that receives information (see, for example, Patent Document 1 below).
JP 61-84132 A

  However, since such a transmitter / receiver is not installed in an existing train or the like, a transmitter / receiver must be newly installed in order to provide video and audio distribution services to passengers according to this method. In addition, when using radio waves, there is an advantage that the number of base stations to be installed can be reduced. However, in order to provide similar distribution services in airplanes, etc., interference by electromagnetic waves becomes a problem. This makes it difficult to operate. In addition, even if wireless communication using light that does not have the problem of interference by electromagnetic waves is used, if a large number of passengers must be serviced, a transmitter for each passenger must be installed, Additional investment that is bulky is required.

  The present invention has been made in order to solve the above-described problems. By using the illumination light of an existing illumination facility without newly preparing a radio radio base station, an optical radio transmitter, or the like, It is an object of the present invention to provide a transmission device that can distribute video and audio to a large number of viewers at low cost.

  In general, a train or an aircraft is provided with a spotlight for reading for each passenger. Conventionally, light bulbs and fluorescent lamps have been used as such lighting fixtures, but in recent years, the advantages of white LEDs (Light Emitting Diodes) for lighting have been attracting attention in terms of durability and cost. It has begun to spread gradually. In the future, light bulbs and fluorescent lamps are considered to replace white LEDs, and if this is used, data transmission will be possible.

  The transmission apparatus according to the present invention pays attention to this point, and stores at least one content of video and audio, and converts the content into a signal of a predetermined format according to a command from the outside and outputs the signal A transmission means for transmitting the signal, a modulation means for modulating the transmitted signal, a light emission means for emitting the modulated visible light, and receiving the visible light of the light emission means, and being superimposed on the visible light. And a reproduction terminal that reproduces video and audio by demodulating the modulated signal.

  With the above-described configuration, the present invention uses an illumination light of an existing illumination facility without newly preparing a radio / radio base station, an optical wireless transmitter, etc. A transmission device capable of delivering audio is provided.

<First Embodiment>
Hereinafter, the present invention will be described in detail based on preferred embodiments shown in the drawings. FIG. 1 is a schematic configuration diagram of a first embodiment of a transmission apparatus according to the present invention. This transmission apparatus superimposes data on the visible light of a spotlight provided for reading on each seat of a train or an aircraft and distributes video and audio to each passenger. Therefore, video information and audio information (hereinafter, collectively referred to as video information) stored in the video transmission unit 11 is transmitted to the vicinity of each passenger via the transmission path 12. This video information is modulated by a modulator 13 installed for each passenger into a form suitable for visible light communication, and then an illumination LED provided for each passenger on the ceiling of the vehicle interior as a current superimposed video data. The light is supplied to the light emitting means 14 constituted by the above. On the other hand, each passenger holds a reproduction terminal 15 equipped with a light receiving means, receives the data superimposed on the visible light using the reproduction terminal 15, and then demodulates it to view video and audio. Yes.

  FIG. 2 is a block diagram showing a detailed configuration of the transmission apparatus shown in FIG. In the figure, a video transmission unit 11 includes, for example, an operation unit 111 that can be operated by a crew member, a memory 112 that temporarily stores content to be played back, and data fetching according to instructions from the operation unit 111. A central processing unit (hereinafter referred to as “CPU”) 113 that writes and reads data to / from the hard disk drive (HDD) 114 that stores content for reproduction, and an Ethernet (registered trademark) interface (I / F) 115. It is configured. The transmission end of the transmission path 12 is connected to the Ethernet (registered trademark) interface 115 constituting the video transmission section 11, and the input end of the modulator 13 is connected to each reception end of the transmission path 12. A light emitting means 14 composed of a white LED or the like is connected to the output end of the modulator 13.

  A reproduction terminal 15 is provided for receiving visible light from the light emitting means 14 and reproducing video and audio. The reproduction terminal 15 receives the visible light and converts it into an electrical signal, a demodulator 152 that extracts an Ethernet (registered trademark) signal from the converted electrical signal, and reproduces the Ethernet (registered trademark) signal as video information. An Ethernet (registered trademark) interface 153 that converts the signal into a signal suitable for the network, a decoder 154 that separates and extracts a video signal and an audio signal from the signal converted by the Ethernet (registered trademark) interface 153, and the decoder 154 The video reproduction unit 155 reproduces video using the video signal extracted from the video signal, and the audio reproduction unit 156 reproduces audio.

  The operation of the transmission apparatus configured as described above will be described below. Video content is stored in the hard disk drive 114. The CPU 113 takes out the video content to be reproduced from the hard disk drive 114 and writes it in the memory 112 in accordance with a command from the operation unit 111 operated by a crew member or the like. The memory 112 has a buffer function. In preparation for the occurrence of an error on the transmission path 12, when a certain amount of video data is taken into the memory 112, the CPU 113 takes out the video data and sends it to the Ethernet (registered trademark) interface 115. Add. The Ethernet (registered trademark) interface 115 converts the video data into an Ethernet (registered trademark) signal such as 100BASE-T. This Ethernet (registered trademark) signal is transmitted to the modulator 13 provided near the user, for example, near the passenger seat, via the transmission path 12.

  In the present embodiment, it is assumed that the video transmission unit 11 is installed in the vicinity of a cockpit or a dedicated machine room in the case of an aircraft, and in the vicinity of a driver's seat or a dedicated machine room in the case of a train. An Ethernet (registered trademark) signal is transmitted to the vicinity of each passenger using the transmission line 12. The transmitted Ethernet (registered trademark) signal is modulated by a modulator 13 into a form suitable for visible light communication, and then emitted as visible light by being superimposed on a drive current by a light emitting means 14 such as a white LED. In addition, since the brightness | luminance of LED is generally low, when using it as a practical lighting fixture, in many cases, dozens of dozens of LED is light-emitted. Therefore, when the illumination light LEDs are used for data transmission, it is necessary to blink these plural LEDs simultaneously.

  On the other hand, in the playback terminal 15, video data is received by the light receiving means 151 such as a photodiode, and the video data is demodulated by the demodulator 152 and extracted as an Ethernet (registered trademark) signal such as 100BASE-T. The Ethernet (registered trademark) interface 153 receives this signal, converts it back into a form suitable for decoding the video signal and the audio signal, and applies them to the decoder 154. The decoder 154 decodes the added signal, separates it into a video signal and an audio signal, and outputs them. Then, the video reproduction unit 155 reproduces the video, and the audio reproduction unit 156 reproduces the audio.

  FIG. 3 is a circuit diagram showing a specific configuration example of the modulator 13, the light emitting unit 14, the light receiving unit 151, and the demodulator 152 constituting the first embodiment. Here, the current generated by the current source 131 is switched between conduction and non-conduction by the switch 132 controlled by the input data. For example, when the input data is “1”, it is conductive and when it is “0”, the current i1 flowing through the LED 141 is controlled accordingly. The LED 141 repeats blinking, and data is displayed using visible light. Is transmitted. On the other hand, on the receiving side, when the transmitted light is received by the photodiode 151, a current i2 corresponding to the blinking of light is generated. A voltage is generated when the current i2 flows through the resistor 158, and data is restored by taking out the voltage.

  In the Ethernet (registered trademark) using 100BASE-T or the like as an input signal to the modulator 13 in the present embodiment, data is encoded using a Manchester code. FIG. 4 shows an example of encoding by Manchester code. In this case, the encoding format is such that clocks having different polarities are output depending on whether the input is “0” or “1”, and “0” continues as input data or “1” continues. Even in this case, the receiving side has a feature that the clock can be reproduced. Further, since the same number of positive voltages and negative voltages appear, there is an advantage that a direct current component can be eliminated. In this embodiment, a 100BASE-T Ethernet (registered trademark) signal encoded by Manchester code is used as an input signal, so that the LED always repeats blinking whatever data is input. Thus, stable transmission becomes possible.

  As described above, according to the first embodiment of the present invention, it is possible to use the illumination light of an existing illumination facility without newly preparing a radio wave base station or an optical radio transmitter. It is possible to distribute video and audio to a large number of viewers at low cost.

<Second Embodiment>
FIG. 5 is a block diagram showing the detailed configuration of the second embodiment of the transmission apparatus according to the present invention corresponding to FIG. 2, and the same reference numerals are given to the same elements as those in FIG. Description is omitted. This embodiment is provided with a plurality of light emitting means 14A, 14B, 14C,..., And correspondingly, modulators 13A, 13B, 13C,... And reproduction terminals 15A, 15B, 15C,. It is configured so that a plurality of passengers can view the same content at the same time. That is, the video data transmitted via each light emitting means 14A, 14B, 14C,... Is simultaneously received by a plurality of playback terminals 15A, 15B, 15C,. Distribution can be performed.

  As described above, according to the second embodiment of the present invention, the illumination light of the existing lighting equipment can be reduced without newly preparing a radio wave base station, an optical wireless transmitter, or the like. Video and audio can be distributed to many viewers at low cost.

  In each of the above-described embodiments, the case where video and audio are distributed has been described. However, the present invention can also be applied to the case where only one of these is distributed.

  In the above-described embodiment, the video transmission unit converts the signal into an Ethernet (registered trademark) signal, and the playback terminal performs reverse conversion. However, instead of the Ethernet (registered trademark) signal, positive and negative voltages are used. Even if other modulation systems appearing in the same number are used, the same operation as described above can be performed.

It is a schematic block diagram of 1st Embodiment of the transmission apparatus which concerns on this invention. It is a block diagram which shows the detailed structure of the transmission apparatus shown in FIG. It is a circuit diagram which shows the specific structural example of the modulator, light emission means, light receiving means, and demodulator which comprise 1st Embodiment. It is explanatory drawing of the Manchester code | cord | chord as an example of the encoding of 1st Embodiment. It is a block diagram which shows the detailed structure of 2nd Embodiment of the transmission apparatus which concerns on this invention.

Explanation of symbols

11 Video transmission unit (transmission means)
12 Transmission path (Transmission means)
13, 13A-13C Modulator (Modulation means)
14, 14A-14C Light-emitting means 15, 15A-15C Reproduction terminal 111 Operation part 112 Memory 113 Central processing unit (CPU)
114 Hard disk drive (HDD)
115, 153 Ethernet (registered trademark) interface 131 Current source 132 Switch 141 LED
151 Light receiving means (photodiode)
152 Demodulator 154 Decoder 155 Video playback unit 156 Audio playback unit 158 Resistance

Claims (1)

Transmitting means for storing at least one content of video and audio, converting the content into a signal of a predetermined format according to an external command, and outputting the signal;
Transmission means for transmitting the signal output from the transmission means;
Modulation means for modulating the signal transmitted by the transmission means;
A light emitting means for emitting visible light modulated by the modulating means;
A reproduction terminal that receives visible light of the light emitting means, demodulates a modulation signal superimposed on the visible light, and reproduces video and audio;
Transmission equipment provided.

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