JPS61202536A - Communication system - Google Patents

Abstract

PURPOSE:To apply high reliability data transmission by adoting the optical communication system and utilizing a light source as a light source so as to decide easily the installing position of the receiver. CONSTITUTION:A data sent from a data transmitter 2 is inputted to a modulator 8 and the modulator 8 modulates the power supply fed to the lighting device 5 according to the sent data. AM or FM modulation system is applied. The receiver 6 detectingthe intensity of light or spectrum detects the light lighted from the lighting device and demodulates a signal. In adopting a sufficient fast modulation speed, the light quantity or spectrum change is not sensed by human eyes. Since the luminous amount itself is viewed by the eye, the reception state of the installed position of the receiver 6 is discriminated easily.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to improvements in communication systems such as LAN (Local Area Network) indoors, inside buildings, underground malls, etc.

(Prior art and its problems) FIG. 2 shows an example of a conventional indoor communication system. 1 indicates the indoor range. 2 is a data transmitter.

Reference numeral 3 indicates a radio transmitter that modulates data sent from the data transmitter 2 and sends it to a radio line, and 4 indicates a radio receiver.

Although FIG. 1 shows a case where indoor communication is performed by wireless communication, wired communication is of course also possible if the installation location of the receiver 4 is limited. The configuration shown in FIG. 2 is an example of data transmission and reception indoors.

In the case of this configuration, it is not possible to obtain a sufficient receiver input voltage to the receiver 4 because a weak electric field method has to be adopted for effective use of radio waves. Another disadvantage is that indoor radio waves have many differences in strength due to fading, and it is difficult to actually measure them, making it difficult to obtain a stable line.

(Objective) In order to eliminate these drawbacks, the present invention is characterized by adopting an optical communication method and using a lighting device as a light source.

(Example) FIG. 1 shows an example of the present invention. In the figure, the same numbers as in FIG. 2 indicate the same functions. 5 is a lighting device, 6
Reference numeral 7 indicates a photodetection receiver, 7 indicates a power source supply terminal for operating the illumination device 5, and 8 indicates a modulator.

This operation is shown next. The data transmitted from the data transmitter 2 is input to the modulator 8, and the modulator 8 modulates the power source supplied to the lighting device 5 according to the transmitted data. As the modulation method, various methods such as AM and Ii'M can be applied. Reference numeral 6 denotes a receiver capable of detecting the intensity or spectrum of light, which detects the light emitted from the lighting device and demodulates the signal. If the modulation speed is made fast enough, the amount of light or the amount of spectrum change will not be perceptible to the human eye. Also.

The disadvantage of the method shown in FIG. 1 is that there is a difference in the strength of the radio waves due to fading, but with the two-wire method, the amount of light itself can be seen with the naked eye, making it easy to judge the reception status at the location where the receiver 6 is installed. In addition, since light does not leak outside the room, there is no interference with other systems, and the number of times the same system can be used repeatedly can be increased.

Although the example explained above is an example of an indoor communication method, the single-line method can be applied not only indoors but also to places where constant lighting is used, such as passages inside buildings and underground malls. In particular, underground malls have complex passages, but each passage is always equipped with lighting equipment, and by simultaneously modulating these lighting equipment, a large system can be effectively constructed.

(Effects) The effects of this invention are that since the visible amount of light is used as a transmission medium, the installation location of the receiver can be easily determined, highly reliable data transmission can be performed, and walls can be Since no light is transmitted beyond this point, the system can be used more efficiently.

[Brief explanation of the drawing]

FIG. 2 shows an example of a conventional indoor communication system, and FIG. 1 shows an embodiment of the present invention. 2: data transmitter, 3: wireless transmitter, 4: wireless receiver,
5: illumination device, 6: light detection receiver, S: , -modulator. 517. .

Claims (1)

[Claims] It consists of a lighting device and a receiver that detects the intensity or spectrum of light, modulates the light amount or spectrum of the lighting device according to a transmission signal, and the receiver detects the light amount or spectrum of the modulated light emitted from the lighting device. , a communication system characterized in that a lighting device doubles as a lighting function and as a transmitter that sends data by demodulating a transmission signal.