JPH03107216A - Weak radio signal communication method - Google Patents

Abstract

PURPOSE:To keep a limited magnetic field strength as a weak radio station by supplying a modulated radio high frequency signal to a cable of flat conductor and detecting an electromagnetic field generated from a hole formed to one face of the conductor with a coupler. CONSTITUTION:Information from a CPU 40 or the like is converted into a modulated radio high frequency signal by a radio equipment 41 and fed to a flat conductor cable 42 whose one surface has holes 73 at a prescribed interval. Then the electromagnetic field corresponding to the modulated radio high frequency signal generated from the holes 73 is coupled respectively to radio equipment 51, 61, detected by couplers 52, 62 provided in the vicinity of the holes 73 and the information from the CPU 40 is communicated in a radio wave to terminal equipments 50, 60. With the method using the couplers, the weak radio signal communication method is realized for a weak radio signal station keeping the limited magnetic field strength.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a weak radio communication method using weak radio waves.

[Prior Art] Conventionally, wireless information communication between a central unit of a computer system and a terminal device in a room such as an office has been performed using an antenna method as shown in FIG.

That is, when transmitting and receiving information wirelessly between the central device 10 and the terminal devices 20 and 30 forming the wireless system 100, the wireless device 11 and antenna 12 are connected to the central device 10, and the terminal device 20 is connected to the wireless device 11 and the antenna 12. A wireless device 31 and an antenna 22 are connected to the terminal device 30, and a wireless device 31 and an antenna 3 are connected to the terminal device 30.
2 are connected to transmit and receive data through the propagation of radio waves between the antennas 12 and 22 and between the antennas 12 and 32.

In addition, in the case of FIG. 1, in addition to the above-mentioned radio system 100, the radio device 11a and the antenna 12a, and the radio device 21a and the antenna 2
Another radio system 200 formed from 2a is also provided.

[Problems to be Solved by the Invention] In the conventional example shown in FIG.
Since the radio waves radiated from the antennas 12, 22.32 of the antenna 0 reach the whole room or even the next room due to spatial propagation, if there is another radio system 200 in the room or in the next room, and the two radio systems 100, 200 have the same When using the carrier frequency, the antenna 12.22.32 of one radio system 100
Radio waves that are not emitted from the radio system 200 become interference radio waves for another radio system 200.

Therefore, it is necessary to take measures such as changing the carrier frequency in one radio system 100 or applying electrical shielding between the two radio systems io0.200, which poses problems in terms of effective use of radio frequencies and economic efficiency. There is.

In addition, when grounding the radio system as described above as a weak radio station that does not require a license, 54 d at a point 3 mm away from the antenna.
Although there is a restriction that the electric field strength must not exceed BμV/m, it is difficult to comply with this restriction and construct a sufficient service area using conventional antenna systems.

An object of the present invention is to eliminate the drawbacks of the prior art described above, to make it possible to coexist a plurality of radio systems using the same carrier frequency within a limited space, and to enable the entire device to cover the entire area within the limited space. An object of the present invention is to provide a weak/weak radio communication method that can maintain the limited electric field strength as a weak radio station even if it is placed in a wide area.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a communication method for wirelessly communicating information between a central device and a terminal device, in which one of two flat conductors arranged at a constant interval. A hole is formed in the flat cable to form a flat cable, a radio device connected to the central device is connected to the cable, and a coupler detects the electromagnetic field generated from the hole in the flat conductor of the flat cable. At the same time, the detected signal is input to the wireless device of the terminal device.

[Operation] According to the above configuration, a flat cable with a hole in one of two flat conductors is used as a radio wave source, and information output from the central device is converted into a carrier wave of a predetermined frequency by a radio. modulate and feed this modulated high frequency signal to the cable,
By detecting the electromagnetic field generated from the cable with a coupler, a modulated high frequency signal is obtained, and by inputting this to the radio of the terminal device, communication using fR weak radio becomes possible.
Multiple wireless systems can coexist.

[Example] A preferred embodiment of the present invention will be described based on the accompanying drawings.

FIG. 1 shows a block diagram of a device implementing the weak radio communication method of the present invention. In the figure, a radio device 41 is connected to a central device 40, and a radio device 51 is connected to each of terminal devices 50 and 60. .61 is connected. A cable 42 that generates an electromagnetic field is connected to the radio 11141 of the central device 40, and a coupler 52.62 that detects the electromagnetic field is connected to each of the radios 51.61. Further, a terminating resistor 43 is connected to the terminal of the cable 42.

Here, the structure of the cable 42 is shown in FIG.
The figure is a projected view of the cable 42. As shown in the figure, the cable 42 has a structure in which a wide conductor plate 72 and a narrow conductor plate 71 are parallel to each other, and a hole 73 is provided in the conductor plate 72. ing. When current is passed through the conductor plates 71 and 72 of the cable 42 in the directions indicated by arrows 75 and 75, an electromagnetic field is induced in the hole 73. Note that 70 is an insulating layer.

Further, the couplers 52 and 62 are of a radiating type with low radiation efficiency, or of a non-radiating type such as an inductive coupling type or a capacitive coupling type.

The cable 42 connected to the radio 141 is laid under a carpet laid on the floor of the office, and a coupling connected to the radio 51.61 is placed directly above the cable 42 on the carpet. Here, a high frequency wave of a predetermined frequency is modulated by the information output from the central device 40 in the wireless radio device 41, the modulated high frequency signal is supplied to the cable 42, and an electromagnetic field is generated from the cable 42. do. Note that the strength of this electromagnetic field is
It is assumed that the output of the radio 41 is adjusted so as not to exceed 54 dBμV/m at a point 3 mm away from the point. By detecting this electromagnetic field by the coupler 52.62, a modulated high frequency signal is obtained at the coupler 52.62, and the unmodulated high frequency signal is supplied to the radio 51.61. The information is demodulated at , and the demodulated information is supplied to the terminal device 50.60.

Another embodiment of the invention is shown in FIGS. 4 and 5.

FIG. 4 is a top view of the planar wave source, and FIG. 5 is a side view of the planar wave source. As shown in FIGS. 4 and 5, the planar wave source includes an insulating layer 80 and an S-shaped flat conductor 81.
82, and has a structure in which holes 83 are provided at appropriate intervals in the wide flat conductor 82 and are distributed in a planar manner.

This planar wave source is used in place of the cable 42 in FIG. 1, and the coupler 5 is connected to the radio equipment 51, 61 in FIG. 1 by laying it all over the office floor.
2.62 can detect the modulated high frequency signal by the radio 41 no matter where it is placed on the floor.

[Effects of the Invention] In summary, according to the present invention, since the distance between the hole provided in the cable conductor and the coupler is narrow, the coupling efficiency is high and the output of the radio can be reduced, so it can be treated as a weak radio. becomes possible. Therefore, a plurality of wireless systems using the same carrier frequency can coexist within one room or building, and frequencies can be used effectively. In addition, not only can multiple wireless systems using the same carrier frequency coexist within a limited space, but even if the entire device is placed in a wide area such as indoors or throughout a building, it is weak. It is possible to comply with the limited electric field strength for wireless.

[Brief explanation of drawings]

Fig. 1 is a detailed perspective view of a flat cable used in the present invention, Fig. 2 is a block diagram of a device implementing the invention, Fig. 3 is a plan view showing another embodiment of Fig. 1, and Fig. 4 is a detailed perspective view of a flat cable used in the present invention. The figure is a side view of FIG. 3, and FIG. 5 is a block diagram showing a conventional communication device. In the figure, 40 is the central device, 41, 50.62 is a radio, 4
2 is the cable, 52.62 is the coupler, 71.72, 81
．． 82 is a flat conductor, and 73° and 83 are holes.

Claims (1)

[Claims] 1. In a communication method for wirelessly transmitting information between a central device and a terminal device, a hole is formed in one of two flat conductors arranged at regular intervals to form a flat cable, and the central A weak signal that is characterized by connecting a radio device connected to the device, detecting the electromagnetic field generated from the hole in the flat conductor of the flat cable with a coupler, and inputting the detected signal to the radio device of the terminal device. Wireless communication method.