JPH0234042A - Close coupling loop and close coupling communication method - Google Patents

Abstract

PURPOSE:To suppress coupling loss between a twist pair cable and a coupling loop and to improve the transmission characteristic by selecting the width of the coupling loop to be a width capable of coupling at least the magnetic field and selecting the width to be a half of a pitch P of the twist pair cable or below. CONSTITUTION:A coupling loop 2 whose width W is a width capable of coupling the magnetic field and whose width is selected to be a half of the pitch P of a twist pair cable 3 or below and the cable 3 are disposed so that the interval is <=0.5P. Since the loop 2 receives only a magnetic field H1 generated from one cross section, an electric signal corresponding to the magnetic field H1 is received. Since the cancellation between the magnetic fields is avoided by selecting the width W to be <=0.5P, the coupling loss due to the cancellation between the magnetic fields of the cable 3 and the loop 2 is suppressed. On the other hand, in order to prevent the reduction in the coupling efficiency with the magnetic field H1, the loop 2 is disposed at the interval of <=0.5P from the cable 3. Thus, the coupling loss between the cable 3 and the loop 2 is suppressed to improve the transmission characteristic.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tightly coupled loop and a tightly coupled communication method, and more particularly to a tightly coupled loop that suppresses coupling loss between a cable and the coupled loop.

(Conventional technology) A conventional tightly coupled loop is shown in FIG.

This is conductor 111.112 and insulator 121.122
A close-coupled loop 2 is disposed near a parallel two-wire cable 1 constituted by the conductors 111 and 112, and the close-coupled loop 2 couples with the magnetic field H generated by the signal current flowing through the conductors 111 and 112. is to be received. That is, the tightly coupled loop 2 receives electrical signals by interlinking with the magnetic field H, and transmits the electrical signals to a circuit such as a connected terminal device. Such a non-contact signal transmission method is, for example, a LAN using a parallel two-wire cable as a pass line.
It can be used for. That is, when a terminal is connected to the coupling loop 2, there is an advantage that the terminal can be moved freely compared to a conventional fixed stationary device.

However, if the magnetic field (T) generated by the parallel two-wire cable is treated as a weak radio station as stipulated by the Radio Law, the electric field strength will become so high that it will not be able to satisfy the prescribed values of the Radio Law.

Therefore, as a measure to reduce the leakage magnetic field to the outside, a twisted pair cable 3 as shown in FIG. 4 is used. This is because the parallel two-wire cables are twisted together at a predetermined pitch P (approximately 50 to 1001 m in the case of VHF band), so the magnetic field H, which is generated every half cycle, faces in the opposite direction. Therefore, at the far position of the cable, the magnetic field ■Il
and the magnetic field H2 cancel each other out. Therefore, the electric field strength is reduced and can meet the specified value under the Radio Law. Further, the coupling loop 2 is formed to have a predetermined width W (generally a width of 0.5 P or less) so as to efficiently couple to the magnetic field by increasing the input impedance to some extent.

[Problem to be solved by the invention]

However, according to the conventional tightly coupled loop, the width of the coupling loop 2 is set to 0.5P or more in order to efficiently couple with the magnetic field, so the magnetic field I], the magnetic field in the opposite direction to the magnetic field)-
12 is coupled with the coupling loop 2, and its component cancels out the component of the magnetic field H,. Therefore, the coupling loss between the twisted pair cable 3 and the coupling loop 2 increases, resulting in a disadvantage that the transmission characteristics deteriorate.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a tightly coupled loop and a tightly coupled communication method that suppress coupling loss between a twisted pair cable and a coupled loop and improve transmission characteristics.

[Means to solve the problem]

In order to achieve the above-mentioned objects, the present invention makes the coupling loop at least wide enough to couple with the magnetic field, and the width is set to 0.5 P or less, where P is the pitch of the twisted pair cable. It provides a tightly coupled loop.

That is, the close coupling loop of the present invention has at least a width capable of coupling with a magnetic field, and the width is formed to be 0.5P or less, where P is the pitch of the twisted pair cable. Therefore, it is possible to eliminate mutual cancellation of magnetic fields, and it is possible to suppress coupling loss between the twisted pair cable and the coupling loop. However, if this is done alone, the coupling efficiency with the magnetic field will decrease as the width of the coupling loop becomes smaller, so by arranging the coupling loop at a distance of 0-5P or less from the twisted pair cable, the width of the coupling loop can be reduced. This covers the associated coupling loss.

Furthermore, the tightly coupled communication method of the present invention includes: installing twisted pair cables twisted at a constant pitch P on a predetermined route; passing a signal current through the twisted pair cables to generate a magnetic field according to the signal; At least one or more close-coupled loops having a width of 0.5P or less with a spacing of 0.5P or less are arranged between the twisted pair cable, and the close-coupling loop is stationary or fixed at a predetermined position. While moving along the twisted pair cable, it is coupled to the magnetic field to perform communication.

〔Example〕

Hereinafter, the tightly coupled loop and tightly coupled communication method of the present invention will be explained in detail.

FIG. 1 shows an embodiment of the present invention, in which a twisted pair cable 3 twisted at a constant pitch P has a width W that can at least couple with a magnetic field (for example, 1/4P or more), and
The coupling loop 2 whose width is 0.5P or less is arranged between the twisted pair cable 3 and the coupling loop 2 so that the interval is 0.5P or less. This coupling loop 2 is adapted to receive only the magnetic field H6 generated from one crossing section. That is, by interlinking with the magnetic field H1, the magnetic field HI
It is possible to receive electrical signals corresponding to .

In this way, by setting the width W to 0.5 P or less,
Cancellation of magnetic fields can be eliminated, and coupling loss due to magnetic field cancellation between the twisted pair cable 3 and the coupling loop 2 can be suppressed. However, the width W of the coupling loop 2
When H7 is made small, the coupling efficiency with the magnetic field H7 is reduced. To prevent this, the coupling loop 2 is connected to the twisted pair cable 3 by 0.
Place them at intervals of 5 points or less.

FIG. 2 shows measurement data representing changes in coupling loss depending on the ratio "G10.5P" of the interval G between the twisted pair cable 3 and the coupling loop 2 to the half pitch (0.5P). As is clear from this result, G10. When S P = 1 is exceeded, the coupling loss increases rapidly, and when G10.5 P≦1,
It can be seen that the increase in coupling loss can be suppressed.

Therefore, it is possible to compensate for the increase in coupling loss caused by the small width of the coupling loop 2. In addition, since the coupling loop is small, the radiation impedance is small, and the generated magnetic field to the external space is reduced. Therefore, the requirements for a weak radio station under the Radio Law can be met.

In the above embodiment, explanation was given using two twisted pair cables and one coupling loop, but multiple twisted pair cables may be provided depending on the bandwidth of transmission data, data amount, etc. A plurality of loops are provided depending on the number of terminal devices based on the LAN configuration. Furthermore, although the coupling loop is depicted as a single-turn loop in FIGS. 1, 3, and 4, it may also have multiple turns. The terminal device connected to the coupling loop may be an information processing device such as a workstation. In that case, it has not only a reception function but also a transmission function.

〔Effect of the invention〕

As explained above, according to the tightly coupled loop and the tightly coupled communication method of the present invention, the coupling loop has a width that is at least capable of coupling with a magnetic field, and the width is 0.5P when the pitch of the twisted pair cable is P. Since the following is achieved, the coupling loss between the twisted pair cable and the coupling loop can be suppressed and the transmission characteristics can be improved.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an embodiment of the present invention, Fig. 2 is a graph showing the relationship between the spacing between the twisted pair cable and the coupling loop and the coupling loss, and Figs. 3 and 4 are the conventional close coupling. A loop is shown, FIG. 3 is an explanatory diagram showing a parallel two-cotton cable, and FIG. 4 is an explanatory diagram showing a twisted pair cable. HS H+, Hz 111. 112 121. 122 ...-Magnetic field conductor/-Insulator

Claims (3)

[Claims] (1) In a tightly coupled loop that couples with the magnetic field generated by applying a signal current to a twisted pair cable twisted at a constant pitch P, the width along the length direction of the twisted pair cable is 0.5 P or less. A tightly coupled loop characterized by the formation of (2) The tightly coupled loop according to claim 1, wherein the tightly coupled loop is arranged with a spacing of 0.5P or less between it and the twisted pair cable. (3) A twisted pair cable twisted at a constant pitch P is installed on a predetermined route, a signal current is passed through the twisted pair cable to generate a magnetic field according to the signal, and a magnetic field is created between the twisted pair cable and the twisted pair cable. . arranging at least one or more close-coupled loops having a width of 0.5P or less with a spacing of 5P or less, and while the close-coupling loops are stationary in a predetermined position or are moved along the twisted pair cable; A tightly coupled communication method, characterized in that communication is performed by coupling with the magnetic field.