JPH10242892A - Signal transmission device, signal output device, and signal transmission member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the feeding of currents in the same direction and to prevent an electromagnetic wave noise from being generated by connecting a couple of connection terminals of a printed wiring board to a couple of connection terminals of another printed wiring board by a couple of signal cables of the signal transmission member through a couple of coils which are magnetically coupled with each other and have the same turns. SOLUTION: Differential signals outputted from the couple of connection terminals 22 of the printed wiring board 12 are transmitted by the couple of twisted signal cables 15 and 16 of a twisted pair cable 14 and inputted to the couple of connection terminals of the other printed wiring board. The coils 23 and 24 which are constituted having the same turns so that they are magnetically coupled with each other are formed of printed wires of a single layer on the printed wiring board 12 on the output side of the differential signals. Wires are so connected that a couple of differential signals outputted by a circuit component 21 are passed through the couple of coils 23 and 24 and transmitted from the connection terminals 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a signal transmission device having a structure in which two printed circuit boards are connected by a signal transmission member, a signal output device including a printed circuit board to which the signal transmission member is connected, and two signal output devices. And a signal transmission member used for connection of the printed wiring board.

[0002]

2. Description of the Related Art Conventionally, when two devices communicate signals, a plurality of connection terminals of two printed wiring boards are individually connected by a plurality of signal cables. The processing speed of recent devices has been improved, and many devices communicate high-resolution color images. Therefore, the frequency of signal transmission is increasing year by year. However, when the frequency at which a signal is transmitted increases, the noise of electromagnetic waves emitted from the signal cable also increases.

In order to solve this problem, as shown in FIG. 12, a twisted pair cable 3, which is a signal transmission member formed by twisting a pair of signal cables 1 and 2, is used for high-frequency signal transmission. For example, in a signal transmission device (not shown) having a structure in which a pair of connection terminals of each of two printed wiring boards are connected by a pair of signal cables 1 and 2 of a twisted pair cable 3, a pair of one of the printed wiring boards is provided. The differential signal output from the connection terminal can be transmitted by the twisted pair cable 3 to a pair of connection terminals of the other printed wiring board. When the pair of twisted signal cables 1 and 2 of the twisted pair cable 3 transmit differential signals, the magnetic fields generated in the differential cables in these signal cables 1 and 2 cancel each other. Therefore, radiation of electromagnetic wave noise can be prevented.

In the signal transmission device using the twisted pair cable 3 as described above, only one of the signal cables 1 and 2 of the twisted pair cable 3 is used for signal transmission.
By passing a return current through the other as an earth cable, the magnetic fields of the signal cables 1 and 2 in the differential mode are offset each other.

[0005]

In the signal transmission apparatus as described above, the transmission of the signal through the twisted pair cable 3 can prevent the generation of electromagnetic noise.

However, even if a differential signal is transmitted over the twisted pair cable 3 or a signal and a return current are transmitted, the balance is not perfect, and a common mode current is generated and electromagnetic wave noise is radiated. Sometimes.

To solve this problem, there is a twisted pair cable 5 provided with a shield member 4 as shown in FIG. 13, but it is still difficult to completely eliminate electromagnetic wave noise. In particular, when such a shield material 4 is connected to the ground wiring of the printed wiring board, a current in a differential mode like a return current is generated in the shield material 4, and high-level electromagnetic wave noise may be radiated.

[0008] The present invention has been made in view of the above problems, and has as its object to provide a signal transmission device, a signal output device, and a twisted pair cable in which generation of electromagnetic noise is more preferably prevented.

[0009]

According to one aspect of the present invention, there is provided a signal transmission apparatus including at least two printed wiring boards provided with at least one pair of connection terminals and at least one pair of twisted signal cables. Consisting of components,
In the signal transmission device in which the pair of connection terminals of each of the two printed wiring boards are connected by the pair of signal cables of the signal transmission member, the pair of signal cables of the signal transmission member are magnetically coupled to each other. A pair of identically wound coils that were individually connected were provided.

In such a signal transmission device, when one of the printed wiring boards outputs a differential signal from a pair of connection terminals, the differential signal is transmitted by a pair of signal cables of a signal transmission member, and the other is transmitted. The signal is input to a pair of connection terminals of the printed wiring board. At this time, the differential signal is transmitted through a pair of coils having the same winding and magnetically coupled to each other. In the pair of magnetically coupled coils of the same winding, it is difficult to pass currents in the same direction, and currents in opposite directions are favorably passed. Therefore, the differential signal is transmitted well in a well-balanced state, and only the current component generated by the fluctuation of the balance is filtered.

The signal transmission member according to the present invention may include a pair of twisted signal cables.
A so-called twisted pair cable is allowed. In the above description, a differential signal is illustrated as a signal transmitted by the pair of signal cables of the signal transmission member. However, the signal transmission device of the present invention includes, for example, one of a pair of signal cables of the signal transmission member. It is also possible to apply only the signal current and to apply the return current by grounding the other. Also, the pair of coils as described above may be present in a signal path connecting two printed wiring boards with a signal transmission member,
As will be described later, it is also possible to form the printed wiring board on the printed wiring board by using printed wiring, or to incorporate the printed wiring board into the connector portion of the signal transmission member.

Further, another signal transmission device according to the present invention is characterized in that two printed wiring boards provided with at least one pair of connection terminals and one ground wire, respectively, at least a pair of twisted signal cables and one ground wire A signal transmission member provided with a cable, the pair of connection terminals of each of the two printed wiring boards being connected by the pair of signal cables of the signal transmission member, and the grounding of the two printed wiring boards. In a signal transmission device in which wiring is connected by an earth cable of the signal transmission member, a pair of coils to which a pair of signal cables of the signal transmission member are individually connected are provided. A pair of coils was provided, and these reverse-wound coils were connected to the ground wiring of the printed wiring board.

In such a signal transmission device, when one of the printed wiring boards outputs a differential signal from a pair of connection terminals, the differential signal is transmitted by a pair of signal cables of a signal transmission member and the other is transmitted. It is input to a pair of connection terminals of the printed wiring board. When a signal is transmitted to the connection terminal of the printed wiring board in this manner, a current in a differential mode is generated in the ground wiring of the printed wiring board and is output to the ground cable of the signal transmission member as a return current. This current is transmitted through a coil that is magnetically coupled in a reverse winding to the coil through which the signal is transmitted. In a pair of coils that are magnetically coupled in this way, currents in the same direction flow well, but currents in the opposite direction are difficult to flow, so current is output from the coil to the ground cable of the signal transmission member. Is suppressed.

In another aspect of the above-described signal transmission device, a shield member for covering a pair of signal cables is provided on the signal transmission member, and the shield member is grounded. In this case, when a signal is transmitted by the signal transmission member, the electromagnetic noise radiated from the signal cable is shielded by the shielded material grounded. As means for grounding the shield material in this way, it is possible to connect the shield material to the ground wiring of the printed wiring board or to connect it to the body frame of the device. The former is selected as a simple structure, and the latter is selected as a more reliable structure.

In another signal transmission device of the present invention, at least two printed wiring boards provided with at least one pair of connection terminals and one ground wiring, and at least one pair of twisted signal cables are made of a shielding material. A pair of the connection terminals of each of the two printed wiring boards are connected by a pair of the signal cables of the signal transmission member, and ground wiring of the two printed wiring boards is formed. In the signal transmission device in which the shield member of the signal transmission member is connected, a pair of coils to which a pair of signal cables of the signal transmission member are individually connected are provided, and these coils are individually magnetically coupled by reverse winding. A pair of coils was provided, and these reverse-wound coils were connected to the ground wiring of the printed wiring board.

In such a signal transmission device, when one of the printed wiring boards outputs a differential signal from a pair of connection terminals, the differential signal is transmitted by a pair of signal cables of a signal transmission member and the other is transmitted. It is input to a pair of connection terminals of the printed wiring board. When a signal is transmitted to the connection terminal of the printed wiring board in this manner, a current in a differential mode is generated in the ground wiring of the printed wiring board and is output to the shielding material of the signal transmission member like a return current. This current is transmitted through a coil that is magnetically coupled in a reverse winding to the coil through which the signal is transmitted. In a pair of coils that are magnetically coupled in this way, currents in the same direction flow well, but currents in the opposite direction are difficult to flow, so current is output from the coil to the shield material of the signal transmission member. Is suppressed.

Further, as another invention of the above-described signal transmission device, each coil is formed by printed wiring on a printed wiring board. In that case, each coil is formed on the printed wiring board together with the ground wiring and the like.

In another aspect of the signal transmission device as described above, two printed wiring boards are provided, each of which outputs a signal, the other receives a signal, and outputs a signal. Was formed. In this case, in a structure in which a pair of coils of the same winding magnetically coupled to a pair of connection terminals of the printed wiring board are connected, a signal is output in a state where the signal is filtered by the coil. Also, in a structure in which a coil of reverse winding is magnetically coupled to a coil connected to a connection terminal of a printed wiring board and connected to a ground wiring, a current is output from the ground wiring of the printed wiring board that outputs a signal to a shield material or the like. Is suppressed.

Further, as another invention in the signal transmission device as described above, the printed wiring of the coil is formed in a single layer. In such a case, if a dead space exists in the printed wiring board, the coil is formed with a simple structure by utilizing the dead space.

Further, as another invention in the above-described signal transmission device, a printed wiring of a coil is formed by a plurality of stacked layers. In that case, a high-performance coil is formed in a small space.

One signal output device of the present invention comprises at least one of a printed wiring board provided with a pair of connection terminals for outputting a signal, and a pair of twisted signal transmission members of a signal transmission member connected to the pair of connection terminals. In a signal output device to which a cable is connected, a pair of same-wound coils magnetically coupled to each other and individually connected to a pair of signal cables of the signal transmission member are formed by printed wiring on the printed circuit board.

In such a signal output device, when a differential signal is output to another printed wiring board, the differential signal is output from a pair of connection terminals to a pair of signal cables of a signal transmission member. The differential signals thus output are transmitted through a pair of coils having the same winding and magnetically coupled to each other. In the pair of magnetically coupled coils of the same winding, it is difficult to pass currents in the same direction, and currents in opposite directions are favorably passed. Therefore, the differential signal is output well in a well-balanced state, and only the current component having the changed balance is filtered.

Another signal output device according to the present invention comprises a printed circuit board provided with a pair of connection terminals at least one of which outputs a signal and a ground wiring to which a ground potential is supplied. In a signal output device to which a pair of twisted signal cables of a signal transmission member is connected, a pair of coils magnetically coupled to each other and individually connected to a pair of signal cables of the signal transmission member are provided on the printed wiring board. A pair of coils formed of printed wiring and individually magnetically coupled to these coils by reverse winding were formed on the printed wiring board by printed wiring, and these reverse-wound coils were connected to the ground wiring.

In such a signal output device, when a differential signal is output to another printed wiring board, the differential signal is output from a pair of connection terminals to a pair of signal cables of a signal transmission member. When a signal is output from the connection terminal in this manner, a current in a differential mode is generated in the ground wire, and this current is transmitted through a coil that is magnetically coupled in a reverse winding to the coil through which the signal is transmitted. In a pair of coils that are magnetically coupled in this way, currents in the same direction pass well, but currents in the opposite direction are difficult to pass, so current is output from the ground wiring to the ground cable of the signal transmission member. Is suppressed.

One signal transmission member according to the present invention comprises a pair of twisted signal cables, and a signal transmission member for connecting a pair of connection terminals of each of two printed wiring boards with the signal cable. A pair of the signal cables are wound around the wire.

In such a signal transmission member, when a differential signal or the like is transmitted by a pair of twisted signal cables, a differential mode magnetic field is generated in the pair of signal cables in opposite directions by these signals, These magnetic fields are well offset by the ferromagnetic wire.

Another signal transmission member of the present invention is a signal transmission member comprising a pair of twisted signal cables and connecting each pair of connection terminals of two printed wiring boards with the signal cable. Is twisted together with the pair of signal cables.

In such a signal transmission member, when a differential signal is transmitted by a pair of twisted signal cables,
Due to these signals, a differential mode magnetic field is generated in a pair of signal cables in opposite directions, and these magnetic fields are favorably canceled via the ferromagnetic wire.

In another aspect of the signal transmission member as described above, the wire is formed of at least one of iron, nickel, and ferrite. In that case, a ferromagnetic wire is easily formed of a general material.

In another aspect of the signal transmission member as described above, the wire is made of a good conductor. In that case, a wire that mediates the magnetic field of the pair of signal cables can be used for the ground cable.

Further, as another invention of the above-described signal transmission member, a shield member for covering a pair of signal cables and a wire is provided. In that case, the shield material prevents the uncancelled magnetic field from being radiated as noise.

In another signal transmission device of the present invention, two printed wiring boards provided with at least one pair of connection terminals are provided, and the pair of connection terminals of each of these printed wiring boards is described above. The signal transmission members of the invention were connected by a pair of twisted signal cables.

In such a signal transmission device, a differential signal or the like can be transmitted from one printed wiring board to the other printed wiring board by a signal transmission member. Electromagnetic noise generated by each signal cable is favorably canceled through the wire.

Further, another signal transmission device of the present invention includes two printed wiring boards provided with at least one pair of connection terminals and one ground wiring, respectively. The pair of signal cables of the signal transmission member of the invention described above were connected to the connection terminals, and a wire was connected to the ground wiring.

In such a signal transmission device, a differential signal or the like can be transmitted from one printed wiring board to the other printed wiring board by a signal transmission member. Electromagnetic noise generated by each signal cable is favorably canceled through the wire. In addition, since the wire of the signal transmission member functions as a ground cable, the ground potential of the two printed wiring boards is kept the same.

Further, another signal transmission device according to the present invention includes two printed wiring boards provided with at least one pair of connection terminals and one ground wiring, respectively. The pair of signal cables of the signal transmission member of the invention described above were connected to the connection terminals, and a wire was connected to the ground wiring, and the shield material of the signal transmission member was grounded.

In such a signal transmission device, a differential signal or the like can be transmitted from one printed wiring board to the other printed wiring board by a signal transmission member. The electromagnetic noise generated by each signal cable is favorably canceled through the wire, and the uncancelled electromagnetic noise is shielded by the grounded shield material. Further, since the wire of the signal transmission member functions as a ground cable, the ground potential of the two printed wiring boards is maintained the same.

Further, another signal transmission device of the present invention includes two printed wiring boards provided with at least one pair of connection terminals and one ground wiring, respectively. The pair of signal cables of the signal transmission member of the invention described above were connected to the connection terminals, and a wire and a shield were connected to the ground wiring.

In such a signal transmission device, a differential signal or the like can be transmitted from one printed wiring board to the other printed wiring board by a signal transmission member. Electromagnetic noise generated by each signal cable is favorably canceled through the wire, and the uncancelled electromagnetic noise is shielded by the shield material connected to the ground wiring of the printed wiring board. further,
Since the wire of the signal transmission member functions as an earth cable, the earth potential of the two printed wiring boards is maintained the same.

[0040]

FIG. 1 shows a first embodiment of the present invention.
This will be described below with reference to FIG. FIG. 1 is a perspective view showing a connection portion between a printed wiring board and a signal transmission member of the signal transmission device, and FIG. 2 is a perspective view showing an entire structure of the signal transmission device.

First, the signal transmission device 11 of the present embodiment
Are two printed circuit boards 12, as shown in FIG.
The printed wiring boards 12 and 13 are connected by the twisted pair cable 14. The twisted pair cable 14 is a signal transmission member.

More specifically, the twisted pair cable 14 is a pair of twisted signal cables 15 and 16.
And connector portions 17 are provided at both ends thereof. Although only one pair of the signal cables 15 and 16 is illustrated here for simplification of the description, other signal cables and ground cables (both not shown) are actually provided. Is referred to as a twisted pair cable 14 here.

The printed wiring boards 12 and 13 are shown in FIG.
As shown in FIG. 1, a signal wiring 19 and a ground wiring 20 are formed by printed wiring on the surface of a substrate body 18, and a circuit component 21 is mounted on such wirings 19 and 20. A large number of connection terminals 22 are provided at one edge of the substrate body 15.
Are provided, and the connection terminals 22 are connected to the wiring 1.
9 and 20 are individually connected.

The connection terminals 22 of the printed wiring boards 12 and 13 and the connector 17 of the twisted pair cable 14 are formed in the same standard, and the connector 17 is detachably connected to the connection terminals 22. ing. In this state, one of the printed wiring boards 1
2 is a predetermined pair of the connection terminals 22 as a signal output device.
And outputs a differential signal, which is a pair of the twisted pair of signal cables 1 of the twisted pair cable 14.
5 and 16 and a predetermined pair of the connection terminals 2 of the other printed wiring board 13 serving as a signal input device.
2 is input.

Then, the signal transmission device 11 of the present embodiment
Then, the printed wiring board 12 on the output side of the differential signal
In addition, as a part of the pair of signal wires 19, a coil 23,
24 are individually formed. These coils 23, 2
Reference numeral 4 denotes a single-layer printed wiring, which is formed in the same winding so as to be magnetically coupled to each other. The ground wiring 20 of the printed wiring boards 12 and 13 is also connected by the ground cable of the twisted pair cable 14.

In the above-described configuration, the signal transmission device 11 of the present embodiment has one printed circuit board 12
Outputs a differential signal from the pair of connection terminals 22, the differential signal is transmitted by the pair of signal cables 15 and 16 of the twisted pair cable 14 and input to the pair of connection terminals 22 of the other printed wiring board 13. Is done. Since the differential signals are transmitted by the twisted pair cable 14 in this manner, the magnetic fields individually generated in the signal cables 15 and 16 are cancelled, and the generation of electromagnetic wave noise is suppressed, and the signal transmission device 11 of the present embodiment Can be transmitted well.

If the balance of the differential signals fluctuates, the balance of the magnetic field of the signal cables 15 and 16 also fluctuates and electromagnetic noise is generated. In the signal transmission device 11 of the present embodiment, the differential Has a function of maintaining a good balance of signals.

That is, a pair of differential signals output from the circuit component 21 is transmitted to the twisted pair cable 14 by the pair of printed wirings 19, and a pair of coils having the same winding and magnetically coupled to each other in the middle. 23 and 24 are transmitted. In the pair of coils 23 and 24 of the same winding magnetically coupled in this way, currents of opposite directions are preferably conducted, but currents of the same direction are not easily conducted.

For this reason, the signal transmission device 1 of the present embodiment
1, the differential signal is output from the printed wiring board 12 to the twisted pair cable 14 in a well-balanced state, and the current component generated due to the fluctuation of the balance is not filtered and output. From generating electromagnetic wave noise.

In particular, since the coils 23 and 24 for maintaining the balance of the differential signal are provided on the printed circuit board 12 on the output side of the differential signal as described above, the differential signal is balanced. After being corrected satisfactorily, the signal is output to the twisted pair cable 14, so that the generation of electromagnetic wave noise is more reliably prevented.

In addition, the signal transmission device 11 of the present embodiment
Since the coils 23 and 24 are formed by printed wiring, they can be easily formed together with the signal wiring 19 and the ground wiring 20. Furthermore, two coils 2
Since 3 and 24 are formed as a single layer, the structure is extremely simple and easy to form.

Further, the signal transmission device 11 of the present embodiment
Now, as described above, the coil 2 that maintains the balance of the signal
Since the printed wiring boards 3 and 24 are provided only on one printed wiring board 12 serving as a signal output device, the structures of the other printed wiring board 13 and the twisted pair cable 14 may be the same as those in the related art.

A shield material is provided on the twisted pair cable 14 as described above, and this shield material is connected to the ground wiring 20 of the printed wiring boards 12 and 13 and the main body frame of the device to be grounded, so that the electromagnetic noise can be more favorably reduced. It is also possible to prevent occurrence.

The present invention is not limited to the above-described embodiment, but allows various modifications without departing from the gist of the invention. For example, in the above embodiment, a differential signal is illustrated as a signal transmitted by the pair of signal cables 15 and 16 of the twisted pair cable 14.
It is also possible to apply a signal current to one of the pair of signal cables 15 and 16 and connect the other to the ground wiring 20 to apply a return current. In the above embodiment, one of the printed wiring boards 12 outputs a signal as a signal output device, and the printed wiring board 12
Although the provision of the coils 3 and 24 has been illustrated, for example, when both of the printed wiring boards 12 and 13 output signals mutually, it is preferable to provide the coils 23 and 24 on both of them.

Further, in the above embodiment, the coil 2 having the same winding
Although it has been exemplified that the layers 3 and 24 are easily formed in a single layer,
As shown in FIG. 3, two layers of coils 25 and 26 can be sequentially laminated to form a four-layer structure as a whole. Coil 2 formed of a single layer as described above
3 and 24 can be easily formed but may require an area to produce the required performance. On the other hand, the coils 25 and 26 composed of a plurality of stacked layers are not easy to form, but can generate high performance with a small area.

Therefore, the coils 23 to 26 as described above are used.
Is preferably selected in consideration of various conditions. For example, when there is an appropriate dead space in the printed wiring board 12, it is preferable to form the single-layer coils 23 and 24 by using the dead space. When the wirings 19, 20 and the like of the printed wiring board 12 are formed in a plurality of layers, the coils 25, 2
6 is preferably formed.

Next, a second embodiment of the present invention will be described with reference to FIG.
This will be described below with reference to FIG. In the present embodiment, the same portions as those in the first embodiment described above are denoted by the same names and reference numerals, and detailed description is omitted. FIG. 4 is a perspective view showing a connection portion between the printed wiring board and the twisted pair cable of the signal transmission device.
FIG. 1 is a perspective view showing the overall structure of a signal transmission device.

First, the signal transmission device 31 of the present embodiment
Also, as shown in FIG. 5, two printed wiring boards 32,
The twisted pair cable 34 is formed to have a structure in which a pair of twisted signal cables 15 and 16 are covered with a shield material 35. The twisted pair cable 34 is a single signal transmission member. I have.

As shown in FIG. 4, one of the printed wiring boards 32, which is a signal output device, includes a coil 36, a part of a pair of signal wires 19 connected to the signal cables 15 and 16 of the twisted pair cable 34, as shown in FIG. 37 are formed individually, but these coils 36 and 37 are not magnetically coupled to each other. And these coils 3
Coils 38 and 39 which are magnetically coupled to the windings 6 and 37 by reverse winding are formed by printed wiring. These coils 38 and 39 are connected to the ground wiring 20.
The ground wire 20 is connected to a predetermined connection terminal 22, and the connection terminal 22 is connected to the twisted pair cable 3.
Four shield materials 35 are connected.

In the configuration described above, the signal transmission device 31 of the present embodiment also employs one printed circuit board 32
Is output from the connection terminal 22 by the pair of signal cables 15 and 16 of the twisted pair cable 34 and transmitted by the pair of connection terminals 2 of the other printed wiring board 33.
2 is input. At this time, since the differential signal is transmitted through the twisted pair cable 34, the signal cables 15, 16
From each other cancels out the electromagnetic noise generated individually. In addition, since the shield member 35 of the twisted pair cable 34 is connected to the ground wiring 20 of the printed wiring boards 32 and 33 and is grounded, the electromagnetic wave noise that has not been completely canceled is shielded by the shield member 35.

However, as described above, the printed wiring board 3
2 outputs a signal from the signal wiring 19 to the twisted pair cable 34, a current in a differential mode is generated in the ground wiring 20. If this current is output to the shield member 35 of the twisted pair cable 34 as a return current, a high level of electromagnetic wave noise will be radiated from the shield member 35, but the signal transmission device 31 of the present embodiment will be described. Has a function of preventing the output of current as described above.

That is, as described above, the current generated in the ground wiring 20 of the printed wiring board 32 in response to the signal output is the coils 38 and 39 which are magnetically coupled in reverse winding to the coils 36 and 37 for transmitting the signal. Is transmitted. The pair of coils 36 and 38 and the coil 3 thus magnetically coupled are
At 7 and 39, currents in the same direction flow well,
Since it is difficult to conduct the current in the opposite direction, the coils 38, 3
From 9, output of current to the shield member 35 of the twisted pair cable 34 is suppressed.

For this reason, the signal transmission device 3 of the present embodiment
In No. 1, when a signal is output from the printed wiring board 32 to the signal cables 15 and 16 of the twisted pair cable 34, unnecessary current is output from the ground wiring 20 to the shield member 35 and electromagnetic noise is prevented from being generated. You.

The present invention is not limited to the above-described embodiment, and allows various modifications without departing from the gist of the present invention. For example, in the embodiment described above, the shield material 35 of the twisted pair cable 34 is connected to the ground wiring 20 of the printed wiring board 32 to prevent unnecessary current output to the shield material 35. It is also possible to connect an earth cable (not shown) of the twisted pair cable 34 to the earth wiring 20 to prevent unnecessary current output to the earth cable.

Further, in the above embodiment, the coils 36 to 39 are each formed in a single layer and laminated in two layers. However, as shown in FIG.
It is also possible to form a four-layer structure as a whole, and it is also possible to form a single layer as a whole and a single layer as a whole.

The signal transmission coils 36,
As with the coils 23 and 24 of the signal transmission device 11 described above, the coils 37 and 24 are magnetically coupled with each other to prevent the current output of the ground wiring 20 and maintain a good balance of differential signals as described above. It is also possible to better prevent the generation of electromagnetic noise.

Next, a third embodiment of the present invention will be described with reference to FIG.
This will be described below with reference to FIGS. In the present embodiment, the same portions as those in the first and second embodiments described above are denoted by the same names and reference numerals, and detailed description is omitted. 7 is a perspective view showing a connection portion between the printed wiring board and the twisted pair cable of the signal transmission device, FIG. 8 is a perspective view showing the entire structure of the signal transmission device, and FIG. 9 is a perspective view showing the twisted pair cable.

The signal transmission device 51 of the present embodiment also has the configuration shown in FIG.
As shown in FIG. 1, the printed wiring boards 52 and 53 are formed in a structure in which they are connected by a twisted pair cable 54 as a signal transmission member. This twisted pair cable 54
Is a pair of signal cables 15, 16 as shown in FIG.
In addition, a ferromagnetic and good conductor wire 55 is formed in a twisted structure, and as shown in FIG.
Are ground cables as the printed wiring boards 52, 5
3 is connected to the ground wiring 20.

In the drawings, the wire 55 is shown to have a thick portion and a thin portion in order to distinguish it from the signal cables 15 and 16, but the wire 55 may have a uniform thickness. As described above, the ferromagnetic and good conductor wire 55 is formed of, for example, iron, an iron-based alloy, nickel, a nickel-based alloy, ferrite, a ferrite-based material, a material obtained by mixing these, or the like. Naturally, such a wire rod 55
The signal cables 15 and 16 are mutually insulated by a vinyl covering or the like.

In the configuration as described above, the signal transmission device 51 of the present embodiment also employs one printed wiring board 52.
Are transmitted to the other printed wiring board 53 by the pair of signal cables 15 and 16 of the twisted pair cable 54.

At this time, the signal transmission device 5 of the present embodiment
1, signal cables 15 and 16 for transmitting differential signals
And the ferromagnetic wire 55 is twisted,
Electromagnetic noise generated individually from the signal cables 15 and 16 is favorably canceled through the wire 55. In addition, the wire 55 of the twisted pair cable 34 is
2 and 53 are connected to the ground wiring 20, so that the printed wiring board 5 can be used without requiring a dedicated ground cable.
2, 53 earth potentials are kept the same.

The present invention is not limited to the above-described embodiment, and allows various modifications without departing from the gist of the present invention. For example, in the above embodiment, the wire 5 is extremely flexible and thin.
5 is twisted together with the signal cables 15 and 16, as shown in FIG. 10, as shown in FIG. 10, the signal cables 15 and 16 are wound around a not so flexible thick wire 61 to form a twisted pair cable 62 as a signal transmission member. As shown in FIG. 11, it is also possible to form a twisted pair cable 63 as a signal transmission member by providing the shield member 35 in the above-described structure, as shown in FIG.

In the above embodiment, the printed wiring boards 52 and 53 having the same structure as the conventional one are connected to the twisted pair cable 54.
Although the connection is illustrated by using the twisted pair cables 54, 63, etc., the signal transmission device 11,
It is also possible to connect 31 printed wiring boards 12, 32.

The above-mentioned twisted pair cable 63
Is connected to the printed wiring board 32, the wire 55
The shield member 35 can be connected to the main body frame while the wire 55 is connected to the ground line 20 in addition to the connection between the shield member 35 and the ground line 20. The former has a simple structure but does not have a high shielding effect, and the latter has a high shielding effect but has a complicated structure. Therefore, it is preferable to select these in consideration of various conditions.

[0075]

Since the present invention is configured as described above, it has the following effects.

The signal transmission device according to the first aspect of the present invention comprises two printed wiring boards each provided with at least a pair of connection terminals, and a signal transmission member provided with at least a pair of twisted signal cables. In a signal transmission device in which the pair of connection terminals of each of the two printed wiring boards are connected by the pair of signal cables of the signal transmission member, the pair of signal cables of the signal transmission member are magnetically coupled to each other. Is provided with a pair of coils of the same winding, so that the balance of signals transmitted by the signal transmission member can be maintained in a good state by the pair of coils of the same winding, so that the signal balance is improved. It is possible to prevent the generation of electromagnetic wave noise due to the fluctuation.

According to a second aspect of the present invention, there is provided a signal transmission apparatus comprising: at least two printed wiring boards provided with at least one pair of connection terminals and one ground wiring; at least one pair of twisted signal cables and one ground; A signal transmission member provided with a cable, the pair of connection terminals of each of the two printed wiring boards being connected by the pair of signal cables of the signal transmission member, and the grounding of the two printed wiring boards. In a signal transmission device in which wiring is connected by an earth cable of the signal transmission member, a pair of coils to which a pair of signal cables of the signal transmission member are individually connected are provided. By providing a pair of coils, and connecting these reverse-wound coils to the ground wiring of the printed circuit board. The coil can prevent the current generated in the ground wiring from being output to the ground cable when the printed wiring board outputs a signal to the signal transmission member, so that electromagnetic wave noise due to unnecessary current being output to the ground cable can be reduced. Generation can be prevented.

The third aspect of the present invention is the first or second aspect.
The signal transmission device according to claim 1, wherein a shield material covering the pair of signal cables is provided on the signal transmission member, and the shield material is grounded, so that when the signal transmission member transmits a signal, the signal is radiated from the signal cable. Electromagnetic noise can be well shielded by a grounded shield material.

According to a fourth aspect of the present invention, there is provided a signal transmission device, wherein at least two printed wiring boards provided with a pair of connection terminals and one ground wiring, and at least a pair of twisted signal cables are made of a shielding material. A pair of the connection terminals of each of the two printed wiring boards are connected by a pair of the signal cables of the signal transmission member, and ground wiring of the two printed wiring boards is formed. In the signal transmission device in which the shield member of the signal transmission member is connected, a pair of coils to which a pair of signal cables of the signal transmission member are individually connected are provided, and these coils are individually magnetically coupled by reverse winding. A pair of coils are provided, and these reverse-wound coils are connected to the ground wiring of the printed wiring board, so that the printed wiring base is provided. Can prevent the current generated in the ground wiring when the signal is output to the signal transmission member from being output to the shield material by the coil, preventing the generation of electromagnetic noise due to the unnecessary current being output to the shield material. can do.

The fifth aspect of the present invention provides the first to fourth aspects.
The signal transmission device according to any one of the above, wherein each coil is formed by printed wiring on a printed wiring board,
Each coil of the printed wiring board can be easily formed together with the ground wiring and the like.

According to a sixth aspect of the present invention, there is provided the signal transmission device according to the fifth aspect, wherein one of the two printed wiring boards outputs a signal, the other receives a signal, and outputs the signal. By forming each coil on the wiring board,
In a structure in which a pair of coils of the same winding that are magnetically coupled to a pair of connection terminals of a printed wiring board are connected, the signal balance can be output after being improved by the coil, and the connection to the connection terminals of the printed wiring board In the structure in which the ground wire is connected to the reverse-wound coil magnetically coupled to the coil thus formed, it is possible to prevent a current from being output from the ground wire of the printed wiring board that outputs a signal to a shield material or the like.

The invention according to claim 7 is directed to claim 5 or 6
In the signal transmission device described above, since the printed wiring of the coil is formed in a single layer, the coil can be formed in a dead space or the like with a simple structure.

The invention described in claim 8 is the invention according to claim 5 or 6.
In the signal transmission device described above, a high-performance coil can be formed in a small space by forming a plurality of stacked printed wiring layers of the coil.

According to a ninth aspect of the present invention, at least one of the signal output devices comprises a printed wiring board provided with a pair of connection terminals for outputting a signal, and a pair of the connection terminals having a twisted signal transmission member. In the signal output device to which the signal cable is connected, a pair of the same winding coils magnetically coupled to each other and individually connected to the pair of signal cables of the signal transmission member are formed by printed wiring on the printed wiring board. Thereby, the balance of the signal output to the signal transmission member can be maintained in a good state by the pair of coils having the same winding, so that the electromagnetic wave noise is generated from the signal transmission member due to the fluctuation of the signal balance. Can be prevented.

According to a tenth aspect of the present invention, there is provided a signal output device comprising:
At least one is composed of a printed wiring board provided with a pair of connection terminals for outputting a signal and a ground wiring to which a ground potential is supplied, and a pair of twisted signal cables of a signal transmission member are connected to the pair of connection terminals. In the signal output device to be formed, a pair of coils that are mutually magnetically coupled and a pair of signal cables of the signal transmission member are individually connected to each other are formed by printed wiring on the printed wiring board,
A pair of coils, each of which is magnetically coupled by reverse winding to each of these coils, is formed on the printed wiring board by printed wiring, and by connecting these reverse-wound coils to the ground wiring, the printed wiring board transmits signals. Since the coil can prevent the current generated in the ground wiring from being output to the ground cable when outputting a signal to the member, it is possible to prevent the generation of electromagnetic noise due to the unnecessary current being output to the ground cable. it can.

The signal transmission member of the invention according to claim 11 is:
In a signal transmission member comprising a pair of twisted signal cables and connecting a pair of connection terminals of each of two printed wiring boards with the signal cable, the pair of signal cables is wound around a ferromagnetic wire. By having
Since the magnetic fields in the differential mode of the pair of signal cables for transmitting the differential signals and the like are favorably canceled via the ferromagnetic wire, the generation of electromagnetic noise can be prevented well.

The signal transmission member according to the twelfth aspect is:
In a signal transmission member composed of a pair of twisted signal cables and connecting each pair of connection terminals of two printed wiring boards with the signal cable, a ferromagnetic wire is twisted together with the pair of signal cables. Thus, the differential mode magnetic field of the pair of signal cables transmitting the differential signal and the like is favorably canceled via the ferromagnetic wire, so that the generation of electromagnetic wave noise can be favorably prevented.

According to a thirteenth aspect of the present invention, there is provided the signal transmission member according to the eleventh or twelfth aspect, wherein the wire is formed of at least one of iron, nickel, and ferrite, so that a general material is provided. A ferromagnetic wire can be easily formed of a material.

According to a fourteenth aspect of the present invention, there is provided the signal transmission member according to any one of the eleventh to thirteenth aspects, wherein the wire material is made of a good conductor, and the wire mediating the magnetic field of the pair of signal cables is grounded. It can be used for

According to a fifteenth aspect of the present invention, there is provided the signal transmission member according to any one of the eleventh to fourteenth aspects, wherein the signal transmission member is not offset by providing a shield material for covering the pair of signal cables and the wire. The emitted magnetic field can be prevented from being radiated as noise by the shield material.

The signal transmission device according to the sixteenth aspect of the present invention
16. A signal transmission member according to any one of claims 11 to 15, wherein two printed wiring boards provided with at least one pair of connection terminals are provided, and the pair of connection terminals of each of these printed wiring boards is twisted. By using a pair of signal cables, it is possible to transmit differential signals from one printed wiring board to the other printed wiring board with a signal transmission member. The generation of electromagnetic wave noise from the member can be better prevented by the wire.

The signal transmission device according to the seventeenth aspect of the present invention
15. A pair of signals of the signal transmission member according to claim 14, wherein two printed wiring boards provided with at least one pair of connection terminals and one ground wiring are provided, and the pair of connection terminals of each of these printed wiring boards is provided. By connecting the cable and connecting the wire to the ground wiring, a differential signal or the like can be transmitted from one printed wiring board to the other printed wiring board by a signal transmission member, and thus the signal is transmitted. In this case, the generation of electromagnetic wave noise from the signal transmission member can be prevented well, and the ground potential of the two printed wiring boards can be kept the same by using a wire without using a dedicated ground cable.

The signal transmission device according to the eighteenth aspect of the present invention
16. A pair of signals of the signal transmission member according to claim 15, wherein two printed wiring boards provided with at least one pair of connection terminals and one ground wiring are provided, and the pair of connection terminals of each of these printed wiring boards is provided. By connecting a cable and connecting a wire to the ground wiring, and grounding the shield material of the signal transmission member, a signal transmission member transmits a differential signal or the like from one printed wiring board to the other printed wiring board. Thus, it is possible to satisfactorily prevent electromagnetic noise from being generated from the signal transmission member when transmitting a signal as described above, and to reduce the number of printed wiring boards by using a wire without using a dedicated ground cable. Earth potential can be maintained the same,
Electromagnetic noise radiated from the signal transmission member can be satisfactorily prevented by the shield material that is reliably grounded.

The signal transmission device according to the nineteenth aspect of the present invention
16. A pair of signals of the signal transmission member according to claim 15, wherein two printed wiring boards provided with at least one pair of connection terminals and one ground wiring are provided, and the pair of connection terminals of each of these printed wiring boards is provided. By connecting a cable and connecting a wire and a shield to the ground wiring, a signal transmission member can transmit a differential signal or the like from one printed wiring board to the other printed wiring board. EMI can be effectively prevented from being generated from a signal transmission member when transmitting a signal to a PC, and the ground potential of two printed wiring boards is kept the same by a wire without using a dedicated ground cable. The electromagnetic noise radiated from the signal transmission member can be effectively prevented by the shield material that is easily grounded. Kill.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a main part of a signal transmission device according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing the entire signal transmission device.

FIG. 3 is a plan view showing a modification of the coil.

FIG. 4 is a perspective view illustrating a main part of a signal transmission device according to a second embodiment of the present invention.

FIG. 5 is a perspective view showing the entire signal transmission device.

FIG. 6 is a plan view showing a modification of the coil.

FIG. 7 is a perspective view illustrating a main part of a signal transmission device according to a third embodiment of the present invention.

FIG. 8 is a perspective view showing the entire signal transmission device.

FIG. 9 is a perspective view showing a twisted pair cable.

FIG. 10 is a perspective view showing a first modification of the twisted pair cable.

FIG. 11 is a perspective view showing a second modification of the twisted pair cable.

FIG. 12 is a perspective view showing a twisted pair cable of a first conventional example.

FIG. 13 is a perspective view showing a second conventional twisted pair cable.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 Signal transmission device 12 Printed wiring board which is a signal output device 13 Printed wiring board 14 Twisted pair cable which is a signal transmission member 15, 16 Signal cable 17 Connector part 18 Substrate main body 19 Signal wiring 20 Ground wiring 21 Circuit parts 22 Connection terminals 23 to Reference Signs 26 Coil 31 Signal transmission device 32 Printed wiring board as signal output device 33 Printed wiring board 34 Twisted pair cable as signal transmission member 35 Shielding material 36 to 41 Coil 51 Signal transmission device 52 Printed wiring substrate as signal output device 53 Printed wiring Substrate 54 Twisted pair cable 55,61 Wire material 62,63 Twisted pair cable signal transmission member

Claims (19)

[Claims] 1. A printed circuit board comprising: two printed circuit boards each provided with at least a pair of connection terminals; and a signal transmission member provided with at least a pair of twisted signal cables. In the signal transmission device in which the pair of connection terminals are connected by the pair of signal cables of the signal transmission member, a pair of windings in which the pair of signal cables of the signal transmission member are individually magnetically coupled to each other. A signal transmission device comprising: a coil; 2. A printed circuit board comprising at least a pair of connection terminals and two printed wiring boards provided with one ground wiring, respectively, and a signal transmission member provided with at least a pair of twisted signal cables and one ground cable. Connecting the pair of connection terminals of each of the two printed wiring boards with the pair of signal cables of the signal transmission member, and grounding the two printed wiring boards with the ground cable of the signal transmission member. In the connected signal transmission device, a pair of coils to which a pair of signal cables of the signal transmission member are individually connected are provided, and a pair of coils which are individually magnetically coupled by reverse winding to these coils are provided. A signal transmission device, wherein a reverse-wound coil is connected to a ground wiring of the printed wiring board. 3. The signal transmission device according to claim 1, wherein a shield member for covering the pair of signal cables is provided on the signal transmission member, and the shield member is grounded. 4. A printed circuit board comprising: two printed wiring boards provided with at least one pair of connection terminals and one ground wire; and a signal transmission member in which at least a pair of twisted signal cables is covered with a shield material, The pair of connection terminals of each of the two printed wiring boards are connected by the pair of signal cables of the signal transmission member, and the shield material of the signal transmission member is connected to the ground wiring of the two printed wiring boards. In the signal transmission device, a pair of coils to which a pair of signal cables of the signal transmission member are individually connected are provided, and a pair of coils which are individually magnetically coupled to the coils by reverse winding are provided. A signal transmission device, wherein the coil is connected to a ground wiring of the printed wiring board. 5. The signal transmission device according to claim 1, wherein each coil is formed on a printed wiring board by printed wiring. 6. The printed wiring board according to claim 5, wherein one of the two printed wiring boards outputs a signal and the other receives a signal, and the coil is formed on the printed wiring board that outputs a signal. Signal transmission device. 7. The signal transmission device according to claim 5, wherein a printed wiring of the coil is formed in a single layer. 8. The signal transmission device according to claim 5, wherein the printed wiring of the coil is formed by a plurality of stacked layers. 9. A signal output device in which at least one is formed of a printed wiring board provided with a pair of connection terminals for outputting a signal, and a pair of twisted signal cables of a signal transmission member are connected to the pair of connection terminals. 2. The signal output device according to claim 1, wherein a pair of coils of the same winding, which are magnetically coupled to each other and are individually connected to the pair of signal cables of the signal transmission member, are formed on the printed circuit board by printed wiring. 10. A printed wiring board provided with a pair of connection terminals at least one of which outputs a signal and a ground wiring to which a ground potential is supplied, wherein the pair of connection terminals comprises a twisted pair of signal transmission members. In the signal output device to which the signal cable is connected, a pair of coils that are magnetically coupled to each other and are individually connected to the pair of signal cables of the signal transmission member are formed on the printed circuit board by printed wiring. A signal output device, comprising: a pair of coils, each of which is magnetically coupled to the coil by reverse winding, is formed on the printed wiring board by printed wiring, and these reverse-wound coils are connected to the ground wiring. 11. A signal transmission member comprising a pair of twisted signal cables and connecting each pair of connection terminals of two printed wiring boards with said signal cable, wherein said pair of signal cables are connected to a ferromagnetic wire. A signal transmission member characterized by being wound. 12. A signal transmission member comprising a pair of twisted signal cables and connecting each pair of connection terminals of two printed wiring boards by said signal cable, wherein a ferromagnetic wire is a pair of said signal cables. A signal transmission member characterized by being twisted together with. 13. The signal transmission member according to claim 11, wherein the wire is made of at least one of iron, nickel, and ferrite. 14. The signal transmission member according to claim 11, wherein the wire is made of a good conductor. 15. The signal transmission member according to claim 11, further comprising a shield member for covering the pair of signal cables and the wire. 16. A signal according to claim 11, wherein two printed wiring boards provided with at least one pair of connection terminals are provided, and each pair of said connection terminals of each of these printed wiring boards is used as a signal. A signal transmission device connected by a pair of twisted signal cables of a transmission member. 17. The signal transmission according to claim 14, wherein two printed wiring boards provided with at least one pair of connection terminals and one ground wiring are provided, and the pair of connection terminals of each of these printed wiring boards is provided. A signal transmission device, wherein a pair of signal cables of a member are connected and a wire is connected to the ground wiring. 18. The signal transmission according to claim 15, wherein two printed wiring boards provided with at least one pair of connection terminals and one ground wiring are provided, and the pair of connection terminals of each of these printed wiring boards is provided. A signal transmission device, comprising connecting a pair of signal cables of a member, connecting a wire to the ground wiring, and grounding a shield material of the signal transmission member. 19. The signal transmission according to claim 15, wherein two printed wiring boards provided with at least one pair of connection terminals and one ground wiring are provided, and the pair of connection terminals of each of these printed wiring boards is provided. A signal transmission device, wherein a pair of signal cables of members are connected, and a wire and a shield are connected to the ground wiring.