JP5764038B2 - Electric field communication device - Google Patents

Description

  The present invention relates to a technique for removing noise during electric field communication.

  According to Patent Document 1, an electric field communication device that induces an electric field in an electric field transmission medium such as a human body and performs data communication using the induced electric field is disclosed. A signal electrode and a ground electrode are arranged inside or outside the case of the electric field communication device, and a communication circuit (transmission circuit, reception circuit) for electric field communication that transmits and receives a data signal from the signal electrode by an electric field is built in the case. ing. The ground electrode is used to acquire a reference potential used during electric field communication in the communication circuit.

  A conventional example using such an electric field communication device is shown in FIG. In this example, both FIG. 5A and FIG. 4B show a portable electric field communication device (hereinafter referred to as a portable transceiver) 100 held by a human body 700 which is an electric field transmission medium, and signals at the feet of the human body 700. It is comprised with the installation type electric field communication apparatus (henceforth installation type transmitter-receiver) 300 in which the electrode 31s and the ground electrode 31g were installed.

  As shown in FIG. 7, the signal electrode 31s of the installation type transceiver 300 is disposed on the side that is contacted or capacitively coupled by the human body 700, and is connected to the signal input / output terminal of the receiving circuit 35 in the housing through the lead wire 32s. ing. On the other hand, the ground electrode 31g is arranged on the floor surface side, and is connected to the ground input terminal (circuit ground) of the receiving circuit 35 through another lead wire 32g.

  Under such a configuration, when the human body 700 carrying the portable transceiver 100 contacts or capacitively couples to the signal electrode 31s of the stationary transceiver 300, arbitrary information stored in advance (for example, identification information of the human body 700, etc.) ) Is output from the signal electrode 11s of the portable transceiver 100, transmitted through the human body 700, received by the signal electrode 31s of the stationary transceiver 300, and transmitted to the receiving circuit 35 via the lead wire 32s. Is done. Thereafter, predetermined processing is performed (for example, authentication processing) by an upper data processing device (not shown) that has received the data signal from the receiving circuit 35.

  In addition, transmission / reception of a data signal is performed using the electric field induced in the human body 700 which is an electric field transmission medium as mentioned above. The specific electric field communication processing technique is disclosed in Cited Document 1.

JP 2001-352298 A

  Such a portable transceiver 100 and a stationary transceiver 300 are used according to various applications, but since there are various noise radiation sources in the actual environment at the time of use, the noise radiation during electric field communication is present. May be affected by noise emitted from the source.

  For example, as shown in FIG. 7A, when a current flows through a power line 500a or a communication line 500b wired inside the wall 500, an electromagnetic field is generated in the vicinity of the wires and radiated from the wall surface. The radiated electromagnetic field is transmitted as noise to the human body 700 located near the wall surface, and is detected by the signal electrode 31s of the installation type transceiver 300 together with the data signal.

  That is, as shown in FIG. 8, the noise radiated from the surface of the wall 500 is transmitted to the signal electrode 31s via the same path as the data signal transmission path (human body 700) at the time of electric field communication. Even if the common mode choke coil 33 is inserted before the circuit 35, noise cannot be removed. Even if the noise filter 34 is inserted, noise in the same band as the data signal in the pass band cannot be removed.

  Further, for example, as shown in FIG. 7B, even when a metal partition 500d having a conductive wall surface is close, noise is radiated over a wide range. In addition, the same applies to the case of noise from electrical equipment connected to a power source, reinforced concrete, noise radiation sources in the ceiling or other rooms.

  As described above, since the data signal output from the electric field communication device and the noise signal emitted from the noise radiation source in the real environment are transmitted through the same path (same electric field transmission medium), they are superimposed on the data signal. There was a problem that noise signal components could not be removed.

  The present invention has been made in view of the above-mentioned problems, and a problem of the present invention is to remove noise in electric field communication.

  2. The electric field communication apparatus according to claim 1, wherein the electric field communication apparatus performs electric field communication by inducing an electric field from the signal electrode to the electric field transmission medium, and a noise radiation source that emits noise to the signal transmission medium and the ground electrode. A first noise applying electrode electrically connected to the lead wire, a lead wire electrically connecting the first noise applying electrode and the ground electrode, and the signal electrode connected to one terminal on the input side. A common mode choke coil in which the ground electrode is connected to the other terminal on the input side, one terminal on the output side of the common mode choke coil is connected to a signal input terminal, and the output side is connected to a ground input terminal. And a receiving circuit for electric field communication to which the other terminal is connected.

  According to the present invention, the first noise applying electrode electrically connected to the noise radiation source for the electric field transmission medium, and the signal electrode for inducing electric field communication in the electric field transmission medium to perform electric field communication are provided on the input side. And a common mode choke coil having a ground electrode connected to the terminal and electrically connected to the first noise applying electrode and connected to the other terminal on the input side. The noise signal included in the data signal can be removed by the noise signal applied to the ground electrode.

  The electric field communication device according to claim 2 is the electric field communication device according to claim 1, wherein the first noise applying electrode is connected to the noise radiation source via a first coupling capacitor between the noise radiation source and the electric field communication device. The amount of noise applied to the ground electrode is adjusted by changing the value of the first coupling capacitance connected.

  According to the present invention, the first noise applying electrode is connected to the noise radiation source via the first coupling capacitance between the noise radiation source and changing the value of the first coupling capacitance, Since the amount of noise applied to the electrode is adjusted, noise can be removed more reliably.

  The electric field communication device according to claim 3 is the electric field communication device according to claim 1 or 2, wherein the second noise application electrode is connected to the ground electrode via a second coupling capacitance between the electric field communication device and the ground electrode. The lead wire electrically connects the first noise applying electrode and the ground electrode by connecting the first noise applying electrode and the second noise applying electrode. The amount of noise applied to the ground electrode is adjusted by changing the value of the second coupling capacitance.

  According to the present invention, the semiconductor device further includes a second noise applying electrode connected to the ground electrode via a second coupling capacitor between the first electrode and the second electrode. The amount of noise applied to the ground electrode is adjusted by electrically connecting the first noise applying electrode and the ground electrode, and changing the value of the second coupling capacitance. Therefore, noise can be removed more reliably.

  The electric field communication apparatus according to claim 4, further comprising an attenuator inserted on a path by the lead wire in the electric field communication apparatus according to any one of claims 1 to 3, wherein the attenuation amount of the attenuator is changed. Thus, the amount of noise applied to the ground electrode is adjusted.

  According to the present invention, it further includes an attenuator inserted on the path of the lead wire, and the amount of noise applied to the ground electrode is adjusted by changing the attenuation amount of the attenuator. Can be removed.

  The electric field communication apparatus according to claim 5 is the electric field communication apparatus according to any one of claims 2 to 4, wherein the amount of noise applied to the ground electrode is transmitted to the signal electrode through the electric field transmission medium. Further, the adjustment is made to be equal to the amount of noise from the noise radiation source.

  According to the present invention, the amount of noise applied to the ground electrode is adjusted to be equal to the amount of noise from the noise radiation source transmitted to the signal electrode via the electric field transmission medium, so that noise can be more reliably reduced. Can be removed.

The electric field communication device according to claim 6 is the electric field communication device according to claim 3 , wherein the signal electrode and the ground electrode are disposed to face each other with the ground electrode on the ground side, and the second noise applying electrode. Is arranged between the ground electrode and the ground.

  According to the present invention, noise in electric field communication can be removed.

It is a figure which shows the structure of the electric field communication system which concerns on 1st Embodiment, and its use condition. It is a figure explaining the effect of the electric field communication system concerning a 1st embodiment. It is a figure which shows a part of other structure of the electric field communication system which concerns on 1st Embodiment. It is a figure which shows the structure of the electric field communication system which concerns on 2nd Embodiment, and its use condition. It is a figure explaining the effect of the electric field communication system concerning a 2nd embodiment. It is a figure which shows a part of other structure of the electric field communication system which concerns on 2nd Embodiment. It is a figure which shows the structure of the conventional electric field communication system. It is a figure explaining the subject of the conventional electric field communication system.

  Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings. However, the present invention can be implemented in many different modes and should not be construed as being limited to the description of the present embodiment.

[First Embodiment]
FIG. 1 is a diagram illustrating a configuration of an electric field communication system according to the first embodiment and a usage state thereof. In this electric field communication system, a portable electric field communication device (hereinafter referred to as a portable transceiver) 100 held by a human body 700 which is an electric field transmission medium, and a signal electrode are installed so that the human body 700 can be contacted or capacitively coupled. It is mainly composed of an installation type electric field communication apparatus (hereinafter referred to as installation type transceiver) 300. Hereinafter, the configuration of the transceivers 100 and 300 will be described.

  The portable transceiver 100 includes a signal electrode 11s, a ground electrode 11g, and a transmission circuit (not shown) for electric field communication connected to each of the electrodes 11s and 11g via different lead wires (not shown). It is mainly configured and provided in one housing.

  The signal electrode 11s is arranged on one inner surface of the housing so that it can be capacitively coupled to the human body 700 in contact with the housing. The ground electrode 11g is disposed opposite to the signal electrode 11s on the other inner surface of the housing with an insulator interposed between the ground electrode 11g and the signal electrode 11s. Then, the side surface of the casing on which the signal electrode 11 s is arranged is held toward the human body 700.

  The portable transmitter / receiver 100 can induce an electric field from the signal electrode 11s to the human body 700 by a transmission circuit and transmit a data signal to the stationary transmitter / receiver 300, which is a communication partner, by the electric field. Furthermore, a receiving circuit for electric field communication can be provided, and transmission / reception of data signals can be realized bidirectionally by the transmitting circuit and the receiving circuit.

  Note that such a portable transceiver 100 has basically the same configuration and function as a conventional electric field communication device. Since the specific electric field communication processing technique using the transmission circuit and the reception circuit is disclosed in the above-mentioned Patent Document 1 and related documents related thereto, description thereof is omitted here.

  On the other hand, in the present embodiment, a first noise application electrode that is capacitively coupled or directly connected to a noise radiation source that radiates noise to the human body 700 is compared with the conventional installed transceiver 300 described in the background art. Newly provided, the same noise as the noise to the human body 700 is received by the first noise applying electrode and applied to the ground electrode, and the signal electrode is passed through the human body 700 by the common mode choke coil provided in the front stage of the receiving circuit. The feature is that the noise received in step 1 is removed by the noise applied to the ground electrode.

  Hereinafter, the wall 500 in which the power line 500a and the communication line 500b are wired will be described as an example of a noise radiation source. Instead of such a wall 500, conductive wall surfaces such as metal partitions and reinforced concrete, and electric devices and communication devices such as personal computers are also examples of noise radiation sources. It is not limited at all.

  As shown in FIG. 1, the installed transceiver 300 includes a signal electrode 31 s and a ground electrode 31 g that are disposed opposite to an inner surface of one housing with an insulator interposed therebetween, and a wall that radiates noise to the human body 700. A first noise applying electrode 31n electrically connected to a part or all of the wall surface of the wall 500 via a first coupling capacitor 36n (capacitance due to capacitive coupling) between the first noise applying electrode 31n and the first noise; A lead wire 32n that directly electrically connects the application electrode 31n and the ground electrode 31g, and a signal electrode 31s is connected to one terminal on the input side via the lead wire 32s, and the input side via the lead wire 32g. A common mode choke coil 33 having a ground electrode 31g connected to the other terminal, and one terminal on the output side of the common mode choke coil 33 connected to one terminal on the input side. A noise filter 34 having the other terminal on the output side of the common mode choke coil 33 connected to the other terminal on the side, and one terminal on the output side of the noise filter 34 connected to the signal input terminal, and a ground input terminal (circuit It is mainly composed of a receiving circuit 35 for electric field communication in which the other terminal on the output side of the noise filter 34 is connected to the ground.

  The signal electrode 31s and the ground electrode 31g are arranged in a housing different from the housing in which the noise filter 34 and the receiving circuit 35 are built so that the signal electrode 31s and the ground electrode 31g can be installed at arbitrary positions on the floor surface through which the human body 700 passes. The signal electrode 31s is set to the empty side and the ground electrode is set to the ground side (floor surface side) so as to be contacted or capacitively coupled, and is installed in the vicinity of the wall 500 that is a noise radiation source.

  Further, it is possible to provide a transmission circuit for electric field communication, and both the reception circuit 35 and the transmission circuit (not shown) induce an electric field from the signal electrode 31s to the human body 700 to both transmit and receive data signals. Can be done.

  Under such a configuration, when the human body 700 carrying the portable transceiver 100 contacts or capacitively couples to the signal electrode 31s of the stationary transceiver 300, arbitrary information stored in advance (for example, identification information of the human body 700, etc.) ) Is output from the signal electrode 11s of the portable transceiver 100, transmitted through the human body 700, which is an electric field transmission medium, and received by the signal electrode 31s of the stationary transceiver 300.

  At this time, radiation noise from the wall 500 installed in the vicinity of the signal electrode 31s is picked up by the human body 700 and transmitted to the human body 700, so that a noise signal is superimposed on the data signal received by the signal electrode 31s. ing.

  On the other hand, the noise radiated from the wall 500 via the first coupling capacitor 36n is collected by the first noise applying electrode 31n capacitively coupled to the wall 500 (capacitive coupling by the first coupling capacitor 36n). Then, it is applied to the ground electrode 31g through the lead wire 32n.

  Thereafter, the data signal after the superposition of the noise signal received by the signal electrode 31s is input to one input side of the common mode choke coil 33 via the lead wire 32s, and the noise signal applied to the ground electrode 31g is the lead wire. It is input to the other input side of the common mode choke coil 33 through 32g.

  Since the same noise signal radiated from the wall 500, that is, a common mode (in-phase) noise signal, is input to the two input sides of the common mode choke coil 33, the common mode choke coil 33 causes the human body 700 The noise signal received by the signal electrode 31 s is removed (attenuated) by the noise signal applied to the ground electrode 31 g, and only the data signal passes through the noise filter 34 and is received by the receiving circuit 35 (FIG. 2). reference).

  The noise filter 34 is designed to pass only the frequency band of the data signal, and other unnecessary frequency band signals are removed (attenuated).

  Thereafter, predetermined processing is performed (for example, authentication processing) by an upper data processing device (not shown) that has received the data signal from the receiving circuit 35.

  Note that the magnitudes of the noise signal received at the signal electrode 31s and the noise signal applied to the ground electrode 31g do not necessarily coincide with each other, so that the ground electrode 31g is changed by changing the value of the first coupling capacitor 36n. The magnitude of the noise signal applied to the signal (hereinafter referred to as noise amount) is adjusted.

  Specifically, for example, a method of changing the distance between the wall 500 and the first noise applying electrode 31n, a method of changing the electrode structure of the first noise applying electrode 31n (for example, electrodes having different thicknesses, In other words, a method of arranging a plurality of types of electrode structures in the vicinity of the wall surface and providing a means for selecting one of them can be used.

  Further, as shown in FIG. 3, an attenuator 37 (for example, a variable attenuator (resistor)) is inserted on the path of the lead wire 32n, and the attenuation amount of the attenuator 37 is changed to be applied to the ground electrode 31g. Adjust the amount of noise.

  Then, by controlling any one or more of the value of the first coupling capacitor 36n and the attenuation amount of the attenuator 37, the amount of noise applied to the ground electrode 31g is transmitted to the signal electrode 31s via the human body 700. The amount of noise from the wall 500 is adjusted to be equal.

  The means, method, mechanism, structure, etc. for adjusting the amount of applied noise by changing the value of the first coupling capacitor 36n and the attenuation amount of the attenuator 37 are not limited to the above example, and are applied to the ground electrode 11g. Any noise can be adopted as long as the amount of noise to be adjusted can be adjusted.

  For example, when a person is standing on the signal electrode 31s and no signal is input, the amount of noise is measured using a spectrum analyzer at the input end of the receiving circuit 35, and the area and wall of the first noise applying electrode 31n are measured. There is a means for searching for a condition that minimizes the measured noise amount by adjusting the distance to 500. Other examples of measuring instruments used for noise measurement include a level meter and an oscilloscope.

  As described above, according to the present embodiment, the first noise application electrode 31n that is capacitively coupled to the wall 500 that emits noise to the human body 700 is newly provided, and the same noise as the noise to the human body 700 is provided. The noise signal received at the signal electrode 31s and the noise signal applied to the ground electrode 31g by the common mode choke coil 33 provided in the previous stage of the receiving circuit 35. Is made common mode, so that the same noise signal component radiated from the wall 500 can be removed.

  That is, even when a noise radiation source is present in the vicinity of the signal electrode 31s, it is possible to eliminate the noise and transmit only a data signal necessary for electric field communication.

  According to the present embodiment, the first noise applying electrode 31n is connected to the wall 500 via the first coupling capacitor 36n between the wall 500 and the value of the first coupling capacitor 36n. Since the amount of noise applied to the ground electrode 31g is adjusted by changing, the noise signal component can be more reliably removed.

  In addition, according to the present embodiment, the attenuator 37 further inserted on the path of the lead wire 32n is provided, and the amount of noise applied to the ground electrode 31g is adjusted by changing the attenuation amount of the attenuator 37. Therefore, the noise signal component can be removed more reliably.

  Further, according to the present embodiment, the amount of noise applied to the ground electrode 31g is adjusted so as to be equal to the amount of noise transmitted from the wall 500 to the signal electrode 31s via the human body 700. The noise signal component can be reliably removed.

  In the present embodiment, the case where the first noise applying electrode 31n is capacitively coupled to the wall 500 has been described as an example. However, when the noise radiation source is a metal (conductor), the first noise is applied. The application electrode 31n and the wall 500 may be electrically connected directly.

  Even in such a case, it is possible to insert the attenuator 37 on the path of the lead wire 32n, and by changing the attenuation amount of the attenuator 37, the amount of noise applied to the ground electrode 31g can be reduced. It can be adjusted to be equal to the amount of noise transmitted from the wall 500 to the signal electrode 31s via.

  In this embodiment, the case where the noise filter 34 is inserted has been described as an example. However, the common mode choke coil 33 and the receiving circuit 35 are electrically connected without inserting the noise filter 34. However, the same effect can be obtained.

  In this case, one terminal on the output side of the common mode choke coil 33 is connected to the signal input terminal of the receiving circuit 35, and the other terminal on the output side of the common mode choke coil 33 is connected to the ground input terminal of the receiving circuit 35. Terminal is connected.

[Second Embodiment]
FIG. 4 is a diagram illustrating a configuration of an electric field communication system according to the second embodiment and a usage state thereof. This electric field communication system is mainly composed of a portable transceiver 100 and a stationary transceiver 300 as in the first embodiment. Hereinafter, differences from the configuration of the electric field communication system described in the first embodiment will be mainly described. Since the other configuration is the same as that of the first embodiment, a duplicate description is omitted.

  The stationary transceiver 300 according to the second embodiment includes a second electrically connected to the ground electrode 31g via a second coupling capacitor 36n2 (capacitance due to capacitive coupling) with the ground electrode 31g. The noise applying electrode 31n2 is further provided, and the second noise applying electrode 31n2 is disposed below the ground electrode 31g, that is, between the ground electrode 31g and the ground (floor surface).

  In addition, in the first embodiment, the lead wire 32n directly connects the first noise applying electrode 31n and the ground electrode 31g, but in the second embodiment, the first noise is applied to the lead wire 32n. The first noise applying electrode 31n1 and the ground electrode 31g are electrically connected by directly connecting the applying electrode 31n1 (first noise applying electrode 31n) and the second noise applying electrode 31n2.

  As described above, even when the second noise application electrode 31n2 capacitively coupled to the ground electrode 31g is further provided and the second noise application electrode 31n2 is connected to the first noise application electrode 31n, Since the noise applying electrode 31n1 and the ground electrode 31g are electrically connected, the common mode choke coil 33 provided in the front stage of the receiving circuit 35 causes the noise received by the signal electrode 31s via the human body 700 to be grounded. It can be removed by noise applied to the electrode 31g (see FIG. 5).

  That is, the common mode choke coil 33 converts the noise signal received by the signal electrode 31s and the noise signal applied to the ground electrode 31g to the common mode, so that the same noise signal component radiated from the wall 500 can be removed. Only data signals can be transmitted.

  As described in the first embodiment, the magnitudes of the noise signal received by the signal electrode 31s and the noise signal applied to the ground electrode do not always coincide with each other. Therefore, the first coupling capacitor 36n1 And the amount of noise applied to the ground electrode 31g are adjusted by changing the value of the second coupling capacitor 36n2.

  Further, as shown in FIG. 6, the amount of noise applied to the ground electrode 31g is adjusted by inserting an attenuator 37 on the path of the lead wire 32n and changing the attenuation amount of the attenuator 37.

  Then, by controlling one or more of the value of the first coupling capacitor 36n1, the value of the second coupling capacitor 36n2, and the attenuation amount of the attenuator 37, the amount of noise applied to the ground electrode 31g is changed to the human body 700. Is adjusted to be equal to the amount of noise transmitted from the wall 500 to the signal electrode 31s via

  As described above, according to the present embodiment, the second noise applying electrode 31n2 connected to the ground electrode 31g via the second coupling capacitor 36n2 between the ground electrode 31g and the second noise applying electrode 31n2 is further provided. By changing the value of the coupling capacitor 36n2, the amount of noise applied to the ground electrode 31g is adjusted, so that the noise signal component can be more reliably removed.

  Even in the case of the present embodiment, as described in the first embodiment, the first noise applying electrode 31n1 and the wall 500 can be electrically connected directly, and the noise can be reduced. It is also possible to electrically connect the common mode choke coil 33 and the receiving circuit 35 without inserting the filter 34.

100: Portable electric field communication device (portable transceiver)
11s ... Signal electrode of portable transceiver 11g ... Ground electrode of portable transceiver 300 ... Installation type electric field communication device (installation type transceiver)
31s ... Signal electrode of stationary transceiver 31g ... Ground electrode of stationary transceiver 31n, 31n1 ... First noise applying electrode 31n2 ... Second noise applying electrode 32s ... Lead wire connected to signal electrode 32g ... Ground electrode 32n ... Lead wire connected to the first noise application electrode 33 ... Common mode choke coil 34 ... Noise filter 35 ... Receiver circuit 36n, 36n1 ... First coupling capacitance 36n2 ... Second coupling capacitance 500 ... Wall 500a ... Power line 500b ... Communication line 700 ... Human body

Claims (6)

In an electric field communication apparatus that performs electric field communication by inducing an electric field from a signal electrode to an electric field transmission medium,
A signal electrode and a ground electrode;
A first noise applying electrode electrically connected to a noise radiation source that radiates noise to the electric field transmission medium;
A lead wire for electrically connecting the first noise applying electrode and the ground electrode;
A common mode choke coil in which the signal electrode is connected to one terminal on the input side, and the ground electrode is connected to the other terminal on the input side;
A receiving circuit for electric field communication in which one terminal on the output side of the common mode choke coil is connected to a signal input terminal, and the other terminal on the output side is connected to a ground input terminal;
An electric field communication device comprising: The first noise applying electrode is connected to the noise radiation source via a first coupling capacitor with the noise radiation source;
2. The electric field communication device according to claim 1, wherein the amount of noise applied to the ground electrode is adjusted by changing a value of the first coupling capacitance. A second noise applying electrode connected to the ground electrode via a second coupling capacitance with the ground electrode;
The lead wire electrically connects the first noise applying electrode and the ground electrode by connecting the first noise applying electrode and the second noise applying electrode,
3. The electric field communication device according to claim 1, wherein the amount of noise applied to the ground electrode is adjusted by changing a value of the second coupling capacitance. And further comprising an attenuator inserted on the lead wire path,
4. The electric field communication device according to claim 1, wherein the amount of noise applied to the ground electrode is adjusted by changing an attenuation amount of the attenuator. 5. The amount of noise applied to the ground electrode is
5. The electric field communication device according to claim 2, wherein the electric field communication device is adjusted to be equal to an amount of noise from the noise radiation source transmitted to the signal electrode through the electric field transmission medium. The signal electrode and the ground electrode are arranged to face each other with the ground electrode on the ground side,
The electric field communication device according to claim 3, wherein the second noise applying electrode is disposed between the ground electrode and the ground.

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