JP2000286586A - Method and cable for connecting between electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a connection method for improving the spurious radiation level of a high-frequency signal. SOLUTION: When spurious radiation is reduced by covering the end part of an external conductor 15 at the reception side of a shielded signal line 14 for connecting electronic equipment with an auxiliary external conductor 17 with a length corresponding to the wavelength of a target radiation eliminating signal, the spurious radiation can be reduced even if mismatching of characteristic impedance occurs at the end part of the reception side, thus achieving stable operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for connecting electronic devices.

[0002]

2. Description of the Related Art As shown in FIG. 4A, in order to transmit a signal from an electronic device 1 to an electronic device 2, a coaxial cable 5 as a connection cable in which a signal line 3 is shielded by an external conductor 4 is used. Then, connection processing is performed as shown in FIG. Here, one end of the signal line 3 is connected to the signal output 6 of the electronic device 1, the other end of the signal line 3 is connected to the signal input 7 of the electronic device 2, and one end of the external conductor 4 is connected to the reference potential of the electronic device 1. 8, and the other end of the external conductor 4 is connected to a reference potential 9 of the electronic device 2.

[0003] As a specific example of the electronic devices 1 and 2, when the electronic device 1 is a video server arranged in a crew room of a passenger aircraft or in the vicinity thereof, the electronic device 2 is provided in a passenger seat of a passenger cabin. Display devices may be mentioned. In this case, the length of the coaxial cable 5 is several tens of meters or more. The video server transmits various control clocks and the like to the display device via the coaxial cable 5 in addition to the video signal. A connector 10 having a coaxial structure is used for connection with the coaxial cable 5 on the video server on the sending side, but various connections such as a connection space are used for connection with the coaxial cable 5 on the display device on the receiving side. At present, a pin connector 11 which does not have a coaxial structure is used due to the restrictions described above.

[0004]

In the above specific example of use, there is a mismatch in the characteristic impedance at the connection point between the coaxial cable 5 and the electronic device 2 (display device). A standing wave based on the reflected signal is generated at the end of the. The standing wave includes a standing wave of a fundamental frequency and a higher-order harmonic of the fundamental frequency. The standing wave leaks into the space from the end of the coaxial cable 5 and communicates in a communication frequency band for communication outside the passenger aircraft. There is a problem that hinders.

[0005] In the above description, only the connection between the video server and a single display device has been described as an example. However, in practice, the video server and the display device installed in each seat are separate. They are connected by coaxial cables, and these coaxial cables are bundled and laid.
Furthermore, at present, the carrier frequency in each of the coaxial cables is not single, and the frequencies of the standing waves at the end of the coaxial cable are various, and mutual standing waves interfere with each other. The end of the coaxial cable is more unstable.

An object of the present invention is to provide a connection method and a connection cable between electronic devices that can reduce unnecessary radiation even when a characteristic impedance mismatch occurs at the receiving end of the connection cable. I do.

[0007]

According to the present invention, there is provided a method for connecting electronic devices to a receiving end of a connecting cable in which a characteristic impedance mismatch occurs. It is characterized in that unnecessary radiation is reduced by covering with an auxiliary external conductor. According to this configuration, unnecessary radiation can be reduced even when mismatching of the characteristic impedance occurs at the receiving end of the connection cable.

[0008]

According to a first aspect of the present invention, when connecting electronic devices with a connection cable, one end of a signal line of the connection cable is connected to a signal of one electronic device of the electronic device. Connected to the output, the other end of the signal line of the connection cable is connected to the signal input of the other electronic device of the electronic device, and a portion between one end and the other end of the signal line of the connection cable is shielded by an external conductor. One end of the conductor is connected to the reference potential of the one electronic device, the other end of the external conductor is connected to the reference potential of the other electronic device, and the end of the external conductor is subjected to target radiation removal. It is characterized in that unnecessary radiation is reduced by covering an auxiliary external conductor having a length corresponding to the wavelength of a signal.

According to a second aspect of the present invention, there is provided a method for connecting electronic devices,
In claim 1, the auxiliary external conductor is DC-connected to a reference potential of the other electronic device. Claim 3
The connection cable described above is a connection cable for connecting between electronic devices, and one end to the other end of a signal line connecting a signal output of one electronic device and a signal input of the other electronic device of the electronic device. An external conductor that shields between the external conductor and an auxiliary external conductor that is covered by the external conductor, has a length corresponding to the wavelength of the target radiation removal signal, and has one end connected to the end of the external conductor. Features.

[0010] The connection cable according to the fourth aspect is the third aspect.
Wherein the end portion of the outer conductor is folded back to form an auxiliary outer conductor. According to a fifth aspect of the present invention, in connecting a main electronic device and a plurality of electronic devices with shielded cables, one end of a signal line of the first cable is connected to the first electronic device. A signal output of the first cable, and the other end of the signal line of the first cable is connected to a signal input of a first electronic device of the plurality of electronic devices. The outside conductor is shielded by an external conductor, one end of the external conductor is connected to the reference potential of the main electronic device, the other end of the external conductor is connected to the reference potential of the first electronic device, and the signal line of the second cable is connected. Is connected to a second signal output of the main electronic device, and the other end of the signal line of the second cable is connected to a signal input of a second electronic device of the plurality of electronic devices. Shield the cable between one end and the other end of the signal line with an external conductor. One end of the conductor is connected to the reference potential of the main electronic device, the other end of the external conductor is connected to the reference potential of the second electronic device, and the first and second cables are bundled at the other end side. 1, the other ends of the outer conductors of the second cable are electrically connected to each other, and the outer conductors are placed outside the bundled first and second cables and have a length corresponding to the wavelength of the target radiation removal signal. It is characterized in that unnecessary radiation is reduced by covering with an auxiliary external conductor.

A connection cable according to a sixth aspect of the present invention is a connection cable for connecting a main electronic device and a plurality of electronic devices with a shielded cable, respectively, wherein the first electronic device includes a first electronic device and the first electronic device. The first cable connecting the main electronic device and the second cable connecting the main electronic device to the second electronic device among the plurality of electronic devices is the first cable of the first and second cables. At the end on the side of the second electronic device, the ends of the outer conductors of the first and second cables are electrically connected to each other, and the outer conductors of the first and second cables are covered with a long length. Is characterized in that a single auxiliary outer conductor having a length corresponding to the wavelength of the target radiation removal signal is provided.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
It will be described based on. It is to be noted that components having the same functions as those in FIG. [Embodiment 1] FIG. 1 shows [Embodiment 1].

FIGS. 1 (a) and 1 (b) show a connection cable 12 of the present invention used for connecting the electronic device 1 (video server) and the electronic device 2 (display device) shown in FIG. 4 (b).
Is shown. One end (the end on the side of the electronic device 1) A of the connection cable 12 is connected to the electronic device 1 using the connector 10 having the same coaxial structure as in the related art, and the other end of the connection cable 12 (the electronic device 2). 1) B is the one shown in FIG.
After (a), they are connected by a connection cable finished as shown in FIG. 1 (b).

The connection cable 12 is shielded from the one end A to the other end B of the signal line 14 covered with the insulator 13 so that the entire length thereof is surrounded by the braided outer conductor 15. The outside of the external conductor 15 is covered with an external coating 16. As shown in FIG. 1A, a braided auxiliary outer conductor 17 is attached to the outer sheath 16 at the other end B of the connection cable 12.
Then, as shown in FIG. 1B, the joint between the other end B of the connection cable 12 and the end of the auxiliary external conductor 17 is soldered 18, and this portion is connected to the plug 19 of the pin connector 11. And the jack 20 are connected to the reference potential 9 of the electronic device 2.

The length L of the auxiliary outer conductor 17 is set as follows according to the wavelength λ of the target radiation removal signal. For example, L = (1/8) · λ is set. In this case, if the frequency of the target radiation removal signal is determined to be 100 MHz, since the wavelength λ is 3 meters, L = 0.37.
5 meters. By providing the auxiliary outer conductor of 37.5 cm, the target radiation removal frequency 1
At 00 MHz, assuming that the waveform is a sine waveform and the peak voltage is V, (1/2) · V at (１ ／) · λ
Radiation, that is, -6 dB. By setting L = (１ ／) · λ, the suppression power is further improved.

Although the auxiliary outer conductor 17 is a braided wire, the same effect can be expected by replacing it with an aluminum foil or a metal pipe. Further, the outer conductor 15 and the auxiliary outer conductor 1
7, the outer conductor 15 is folded back at the other end B of the connection cable 12 to the outside of the outer sheath 16 to have a length L.
May be configured as the auxiliary external conductor 17.

[Embodiment 2] FIG. 2 shows [Embodiment 2].
Is shown. [Embodiment 1] has described an example in which a pair of electronic devices 1 and 2 are connected by a connection cable 12, but in [Embodiment 2], a main electronic device 21 and a plurality of electronic devices are connected. First and second cables 24, 25 of shielded signal lines 14a, 14b connecting between 22, 22
In the example shown in FIG.

The main electronic device 21 (video server) and the first
One end (the end on the side of the main electronic device 21) A of the first cable 24 connecting between the electronic devices 22 is connected to the main electronic device 21 by using the connector 10 having a coaxial structure as in the related art. The other end B of the first cable 24 is connected to the first electronic device 22 by the pin connector 11 having no coaxial structure.

One end of a second cable 25 connecting between the main electronic device 21 and the second electronic device 23 (the main electronic device 21).
Is connected to the main electronic device 21 using a connector 10 having the same coaxial structure as in the prior art, and the other end B of the second cable 25 is connected to the pin connector 1 having no coaxial structure.
1 is connected to the second electronic device 23. At the other end B of the first and second cables 24 and 25 laid in a bundle,
A single auxiliary outer conductor 26 is put on the outside of the bundled first and second connection cables 24 and 25, and the end of the auxiliary outer conductor 26 is soldered 27 to the outside of the first and second cables 24 and 25. The other ends B of the conductors 28 and 29 are electrically connected to each other.

The length L of the auxiliary outer conductor 26 is set in accordance with the wavelength λ of the target radiation removal signal, as in the first embodiment, so that unnecessary radiation can be reduced. The reason why it is effective to cover the single auxiliary outer conductor 26 as shown in FIG. 2 as compared with the comparative example of FIG. 3 will be described. When the carrier frequency of the first signal output 30 and the carrier frequency of the second signal output 31 of the main electronic device 21 are different, the first and second cables 24 and 24 in which characteristic impedance mismatch has occurred. At the end of 25, standing waves of different frequencies are generated and unstable.

As a method of solving this instability, as shown in a comparative example shown in FIG. 3, the outer coatings 32a and 32b of the ends of the first and second cables 24 and 25 are extended over a length D in FIG.
It is conceivable that the end of the outer conductor 28 of the connection cable 24 and the end of the outer conductor 29 of the connection cable 25 are electrically connected to each other by soldering 33 to have the same potential. However, in this case, in an operating environment where the temperature becomes low during the flight over the air, such as an aircraft, the water condenses due to dew condensation and freezes, and the land freezes and the frost melts and gets wet. Outer covering 3 of cables 24 and 25
When the strips 2a and 32b are stripped long over the length D, the gaps between the outer coatings 32a and 32b and the outer conductors 28 and 29 and the gap between the insulator 13 and the outer conductors 28 and 29 cause Water enters the outer conductor 2
The corrosion of 8,29 progresses rapidly and a stable shielding effect cannot be expected for a long period of time.

On the other hand, as shown in [Embodiment 2] shown in FIG. 2, the state at the end B of the first and second cables 24 and 25 is stabilized by covering with a single auxiliary outer conductor 26. In this case, the amount of stripping of the outer coatings 32a and 32b is smaller in each stage than in the comparative example of FIG. Intrusion of moisture can be prevented, and a stable shielding effect can be expected over a long period of time as compared with the comparative example shown in FIG.

Although the auxiliary outer conductor 26 is a braided wire, the same effect can be expected by replacing it with an aluminum foil or a metal pipe.

[0024]

As described above, according to the method for connecting electronic devices of the present invention, unnecessary radiation is reduced by covering the end of the external conductor with the auxiliary external conductor having a length corresponding to the wavelength of the target radiation removal signal. Therefore, unnecessary radiation can be reduced even when characteristic impedance mismatch occurs at the receiving end of the connection cable. Therefore, even if the arrangement interval between the connected electronic devices is long, and a high-frequency signal (frequency range of tens of MHz or more) is transmitted, or a case where a high-frequency digital signal is transmitted is assumed. Stable operation can be expected.

[Brief description of the drawings]

FIG. 1 is a connection cable and connection diagram according to a first embodiment of the present invention.

FIG. 2 is a connection diagram according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a comparative example.

FIG. 4 is a configuration diagram illustrating a conventional connection method.

[Explanation of symbols]

 1, 2 electronic equipment 3 signal line 4 outer conductor 5 coaxial cable 6 signal output 7 signal input 8 reference potential of electronic equipment 1 9 reference potential of electronic equipment 2 10 connector with coaxial structure 11 pin connector without coaxial structure 12 connection cable 13 Insulator 14 Signal line 15 Outer conductor 16 Outer sheath 17 Auxiliary outer conductor 18 Soldering 19 Plug 20 Jack 21 Main electronic device 22 First electronic device 23 Second electronic device 24 First cable 25 Second cable 26 Auxiliary External conductor 27 Soldering 28, 29 External conductor 30 First signal output of main electronic device 21 31 Second signal output of main electronic device 21 32a, 32b External coating 33 Soldering

Claims (6)

[Claims] When connecting electronic devices with a connection cable, one end of a signal line of the connection cable is connected to a signal output of one of the electronic devices, and the other end of the signal line of the connection cable is connected to the other end. It is connected to the signal input of the other electronic device of the electronic device, one end to the other end of the signal line of the connection cable is shielded by an external conductor, and one end of the external conductor is connected to the reference potential of the one electronic device. Connecting the other end of the external conductor to a reference potential of the other electronic device, and covering an end portion of the other electronic device of the external conductor with an auxiliary external conductor having a length corresponding to a wavelength of a target radiation removal signal. A connection method between electronic devices that reduces unnecessary radiation. 2. The method according to claim 1, wherein the auxiliary external conductor is DC-connected to a reference potential of the other electronic device. 3. A connection cable for connecting electronic devices, wherein one end of the signal line connecting a signal output of one of the electronic devices and a signal input of the other electronic device is connected between one end and the other end of the signal line. A connection cable comprising: an outer conductor that shields the outer conductor; and an auxiliary outer conductor that is covered by the outer conductor, has a length corresponding to the wavelength of the target radiation removal signal, and has one end connected to an end of the outer conductor. 4. The connection cable according to claim 3, wherein an end of the outer conductor is turned back to form an auxiliary outer conductor. 5. When each of the main electronic device and the plurality of electronic devices is connected by a shielded cable, one end of a signal line of the first cable is connected to a first signal output of the main electronic device. Connecting the other end of the signal line of the cable to the signal input of the first electronic device of the plurality of electronic devices, shielding between the one end and the other end of the signal line of the first cable with an external conductor, One end of this external conductor is connected to the reference potential of the main electronic device, the other end of the external conductor is connected to the reference potential of the first electronic device, and one end of the signal line of the second cable is connected to the 2, the other end of the signal line of the second cable is connected to the signal input of the second electronic device of the plurality of electronic devices, and the other end of the signal line of the second cable is connected to the other end. Shield between the ends with an external conductor, and connect one end of this external conductor to the main electronic device. Connected to the reference potential, connect the other end of the outer conductor to a reference potential of said second electronic apparatus, first, the first by bundling a second cable the other end,
The other end of the outer conductor of the second cable is electrically connected to each other, and is placed over the outside of the bundled first and second cables and has a length corresponding to the wavelength of the target radiation removal signal. A connection method between electronic devices that reduces unnecessary radiation by covering conductors. 6. A connection cable for connecting a main electronic device and a plurality of electronic devices with shielded cables, respectively, connecting the main electronic device and a first electronic device of the plurality of electronic devices. The first cable, the second cable connecting the main electronic device and the second electronic device among the plurality of electronic devices, is connected to the first and second electronic device side of the first and second cables. , And electrically connect the ends of the outer conductors of the first and second cables to each other, and cover the outer ends of the bundled first and second cables with a length corresponding to the target radiation removal signal. Connection cable with a single auxiliary outer conductor of a length corresponding to the wavelength.