JP2010213064A - Transceiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce an influence of noise entering a transmission line up to an external electrode part. <P>SOLUTION: A level adjustment circuit 13 attenuates a signal between an other end 21B of a first transmission line 21 and an other end 22B of a second transmission line 22 to apply it to between a first electrode 11 and a second electrode 12 in a transmission period, and also amplifies a signal between the first electrode 11 and second electrode 12 to apply it to between the other ends 21B and 22B in a reception period. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a transceiver that transmits and receives signals by inducing an electric field in an electric field transmission medium.

  In recent years, there has been research on communication performed by inducing an electric field in an electric field transmission medium such as a human body (see Non-Patent Document 1).

"Redtacton", [online], Nippon Telegraph and Telephone Corporation, [Search February 1, 2008], Internet [URL: http://www.redracton.com/]

  FIG. 5 is a diagram showing a schematic configuration of such a conventional transceiver.

  The transceiver includes an external electrode unit 1 </ b> A, a signal cable 2, and a transmission / reception circuit 3. The external electrode unit 1 </ b> A includes a first electrode 11 and a second electrode 12. The transmission / reception circuit 3 includes a transmission circuit, a reception circuit (not shown), a control circuit for driving them, and the like. If the signal transmission path between the external electrode unit 1A and the transmission / reception circuit 3 is ideally balanced, noise entering the signal cable 2 from the outside has the same phase and the same intensity and can be eliminated by differential reception.

  However, in the transceiver of FIG. 5, it is impossible to actually keep the signal transmission path (mainly the signal cable 2) completely balanced. Further, the signal transmission path has a finite length, and depending on the application, it is necessary to lengthen the signal cable 2. For example, considering the case where the installation location of the transceiver is limited, a maximum length of about 100 m is assumed. For this reason, a signal for transmitting and receiving information is affected by the following noise during reception and transmission operations of the transceiver. During the reception operation, the electric field received by the external electrode section is very small, and the influence of noise received by the transmission line (mainly the signal cable) to the reception circuit is large. During the transmission operation, the signal from the transmission circuit must be kept at a very low level in order to prevent the electric field induced in the external electrode portion from being wireless and propagating through the space. For this reason, the influence of the noise received by the transmission line to the external electrode part is large. Thus, the conventional transceiver has a problem that the influence of external noise is large.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a transceiver capable of reducing the influence of noise entering the transmission line to the external electrode section.

  A transceiver according to a first aspect of the present invention includes a first electrode and a second electrode, a first transmission line and a second transmission line, and one end of the first transmission line and one end of the second transmission line in a transmission period. A transmission / reception circuit for receiving a signal between the one end in the reception period and a signal between the other end of the first transmission line and the other end of the second transmission line in the transmission period. A level adjusting circuit that amplifies a signal between the first electrode and the second electrode and amplifies a signal between the first electrode and the second electrode and applies the signal between the other end during the reception period; It is characterized by providing.

  A transceiver according to a second aspect of the present invention includes a first electrode and a second electrode, a first transmission line and a second transmission line, a first conductor and a second conductor, and the first conductor and the second conductor in a transmission period. A transmission / reception circuit that applies a signal between the conductors and receives a signal between the first conductor and the second conductor in a reception period, and a direct current is applied to the signal between the first conductor and the second conductor in a transmission period. Is applied between one end of the first transmission line and one end of the second transmission line, and a signal between the one end is applied between the first conductor and the second conductor in the reception period. In the DC superposition circuit and the transmission period, the signal between the other end of the first transmission line and the other end of the second transmission line is attenuated and applied between the first electrode and the second electrode, and in the reception period , Amplifying the signal between the first electrode and the second electrode, between the other end Characterized in that it comprises a level adjusting circuit for applying to.

  According to the present invention, it is possible to reduce the influence of noise entering the transmission line up to the external electrode section.

It is a figure which shows schematic structure of the transceiver which concerns on the 1st Embodiment of this invention. It is a figure which shows the detailed structure of the transceiver which concerns on embodiment shown in FIG. It is a figure which shows schematic structure of the transceiver which concerns on the 2nd Embodiment of this invention. It is a figure which shows the detailed structure of the transceiver shown in FIG. It is a figure which shows schematic structure of the conventional transceiver.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram showing a schematic configuration of the transceiver according to the first embodiment, and FIG. 2 is a diagram showing a detailed configuration of the transceiver shown in FIG.

  The transceiver performs half-duplex communication with a not-shown counterpart transceiver using a human body or the like as an electric field transmission medium, and includes an external electrode unit 1, a signal cable 2, and a transmission / reception circuit 3. The external electrode unit 1 includes a first electrode 11, a second electrode 12, and a level adjustment circuit 13. The signal cable 2 includes a first transmission line 21 and a second transmission line 22.

  The transmission / reception circuit 3 applies a signal between one end 21 </ b> A of the first transmission line 21 and one end 22 </ b> A of the second transmission line 22 in a transmission period in which a signal is transmitted to the other party. In the present embodiment, the signal is an AC signal including information to be transmitted to the other party. Noise that has propagated through the surrounding space enters the signal cable 2, but the transmission / reception circuit 3 applies a large signal in order to increase the ratio (SN ratio) of the signal magnitude to the noise magnitude. The transmission / reception circuit 3 can increase the signal level.

  The level adjustment circuit 13 includes an attenuator 131 and a differential amplifier 132 having a resistance component, a switch 133 that connects the first electrode 11 to one end 131A of the attenuator 131 or the first input terminal 132A of the differential amplifier 132, a first A switch 134 that connects or disconnects the other end 21B of the transmission line 21 to or from the other end 131B of the attenuator 131, and a capacitance (element having capacitance) 135 having one end 135A connected to the output terminal of the differential amplifier 132; And a switch 136 for connecting or disconnecting the other end 21B of the first transmission line 21 to the other end 135B of the capacitance 135. The second electrode 12, the other end 22B of the second transmission line 22, the second input terminal 132B of the differential amplifier 132, and the ground terminal of the differential amplifier 132 are connected to each other. Each switch has a solenoid S. The solenoid S has a conductor piece, a coil, and a movable iron core (not shown). By supplying electric power to the coil, the movable iron core moves and the conductor piece is also interlocked.

  The transmission / reception circuit 3 transmits a transmission / reception switching signal 31 to the external electrode unit 1. In the transmission period, transmission is instructed by the transmission / reception switching signal 31. Thereby, supply of electric power to each solenoid S is stopped. The switch 133 connects the first electrode 11 to one end 131 </ b> A of the attenuator 131. The switch 134 connects the other end 21 </ b> B of the first transmission line 21 to the other end 131 </ b> B of the attenuator 131. The switch 136 disconnects the other end 21 </ b> B of the first transmission line 21 from the other end of the capacitance 135.

  Thereby, a signal generated between the other end 21 </ b> B of the first transmission line 21 and the other end 22 </ b> B of the second transmission line 22 is attenuated by the attenuator 131. The attenuated signal is applied between the first electrode 11 and the second electrode 12 (hereinafter referred to as “between electrodes”).

  Here, the level adjustment circuit 13 attenuates the signal to such a magnitude that the electric field generated between the electrodes propagates through the space as a radio signal and does not adversely affect the surroundings. Thereby, the bad influence on the surrounding environment resulting from the noise which enters into the signal cable 2 is reduced.

  For example, the first electrode 11 generates an electric field with the ground, and the second electrode 12 generates an electric field with an electric field transmission medium (not shown). The counterpart transceiver receives the signal via the ground and the electric field transmission medium. Since the signal between the electrodes is attenuated, the received signal is also small. However, since the SN ratio in the signal cable 2 is increased, the SN ratio in the received signal is also large. Therefore, the counterpart transceiver can easily extract the original signal. That is, adverse effects on the counterpart transceiver due to noise entering the signal cable 2 are reduced.

  On the other hand, in the reception period, the counterpart transceiver generates a signal, and an electric field corresponding to the signal is generated between the ground and the electric field transmission medium. Thereby, for example, an electric field is generated between the electric field transmission medium and the first electrode 11, an electric field is generated between the ground and the second electrode 12, and a signal corresponding to the signal from the counterpart transceiver is generated between the electrodes. Arise.

  The transmission / reception circuit 3 instructs reception by the transmission / reception switching signal 31 during the reception period. As a result, power is supplied to each solenoid S and differential amplifier 132 of the level adjustment circuit 13 during the reception period. The switch 133 connects the first electrode 11 to the first input terminal 132A of the differential amplifier 132. The switch 134 disconnects the other end 21 </ b> B of the first transmission line 21 from the attenuator 131. The switch 136 connects the other end 21 </ b> B of the first transmission line 21 to the other end of the capacitance 135.

  Thereby, the signal generated between the electrodes is amplified by the differential amplifier 132, and the amplified signal is applied between the other end 21 </ b> B of the first transmission line 21 and the other end 22 </ b> B of the second transmission line 22. The transmission / reception circuit 3 receives a signal via the signal cable 2. Although noise enters the signal cable 2, since the level adjustment circuit 13 amplifies the signal, the signal-to-noise ratio in the signal cable 2 is large, so that the transmission / reception circuit 3 can easily extract the original signal. That is, it is possible to reduce an adverse effect on the own transceiver due to noise entering the signal cable 2.

  As described above, the transceiver according to the first embodiment includes the first transmission line 21 in the first electrode 11 and the second electrode 12, the first transmission line 21 and the second transmission line 22, and the transmission period. A signal is applied between one end 21A of the second transmission line 22 and one end 22A of the second transmission line 22, and the transmission / reception circuit 3 receives the signal between the one end in the reception period, and the first transmission line 21 in the transmission period. A signal between the other end 21B of the second transmission line 22 and the other end 22B of the second transmission line 22 is attenuated and applied between the first electrode 11 and the second electrode 12, and the first electrode 11 and the second electrode 12 are received during the reception period. And a level adjustment circuit 13 for amplifying the signal between the other ends 21B and 22B.

  Specifically, the second electrode 12 and the other end 22B of the second transmission line 22 are connected to each other, and the level adjustment circuit 13 includes an attenuator 131 and a differential amplifier 132, and the first electrode 11 is connected to one end 131A of the attenuator 131 or A switch 133 connected to the first input terminal 132A of the differential amplifier 132, a switch 134 connecting or disconnecting the other end 21B of the first transmission line 21 to the other end 131B of the attenuator 131, and an output terminal of the differential amplifier 132 A capacitance 135 having one end 135A connected thereto and a switch 136 for connecting or disconnecting the other end 21B of the first transmission line 21 to or from the other end 135B of the capacitance 135 are provided.

  Therefore, the SN ratio in the signal cable 2 can be increased in the transmission period and the reception period, and as a result, the influence of noise can be reduced.

[Second Embodiment]
FIG. 3 is a diagram showing a schematic configuration of the transceiver according to the second embodiment, and FIG. 4 is a diagram showing a detailed configuration of the transceiver shown in FIG.

  The transceiver has a configuration similar to that of the transceiver according to the first embodiment, and the same reference numerals are given to the same components. Hereinafter, differences from the first embodiment will be described.

  The transceiver includes an external electrode unit 1, a signal cable 2, a transmission / reception circuit 3, and a DC superimposing circuit 4.

  The transmission / reception circuit 3 applies a signal between the first conductor 51 and the second conductor 52 in the transmission period. The transmission / reception circuit 3 applies a large signal in order to increase the SN ratio in the signal cable 2.

  The DC superimposing circuit 4 includes a conductor 41 and a DC power source 42, a capacitance 43 having one end 43 </ b> A connected to one electrode 42 </ b> A of the DC power source 42, and one end 21 </ b> A of the first transmission line 21 to the other end of the DC power source 42. The switch 44 is connected to the electrode 42 </ b> B or the conductor 41, and the switch 45 is connected to the other end 43 </ b> B of the capacitance 43 or the conductor 41. The second conductor 52 and one end 22A of the second transmission line 22 are connected to each other. Each switch has a solenoid S.

  The transmission / reception circuit 3 transmits a transmission / reception switching signal 31 to the DC superimposing circuit 4. In the transmission period, transmission is instructed by the transmission / reception switching signal 31. Thereby, the supply of electric power to each solenoid S of the DC superimposing circuit 4 is stopped. In this case, the switch 44 connects the one end 21 </ b> A of the first transmission line 21 to the conductor 41. The switch 45 connects the first conductor 51 to the conductor 41.

  As a result, the signal applied between the first conductor 51 and the second conductor 52 is applied between the one end 21A of the first transmission line 21 and the one end 22A of the second transmission line 22, and the first transmission line A signal is generated between the other end 21 </ b> B of 21 and the other end 22 </ b> B of the second transmission line 22.

  The level adjustment circuit 13 includes an inductor (an element having an inductance) 137 having one end connected to the power supply terminal of the differential amplifier 132 in addition to the configuration of the first embodiment. The switch 134 connects the other end 21 </ b> B of the first transmission line 21 to the other end 131 </ b> B of the attenuator 131 or the other end of the inductor 137.

  In the transmission period, a signal generated between the other end 21 </ b> B of the first transmission line 21 and the other end 22 </ b> B of the second transmission line 22 is supplied to each solenoid S of the level adjustment circuit 13. The signal does not have enough energy to move the movable iron core of each solenoid S. In this case, the switch 133 connects the first electrode 11 to one end 131 </ b> A of the attenuator 131. The switch 134 connects the other end 21 </ b> B of the first transmission line 21 to the other end 131 </ b> B of the attenuator 131. The switch 136 disconnects the other end 21B of the first transmission line 21 from the other end 135B of the capacitance 135.

  Thereby, a signal generated between the other end 21 </ b> B of the first transmission line 21 and the other end 22 </ b> B of the second transmission line 22 is attenuated by the attenuator 131. The attenuated signal is applied between the electrodes. Here, the level adjustment circuit 13 attenuates the signal to such a magnitude that the electric field generated between the electrodes propagates through the space as a radio signal and does not adversely affect the surroundings. As a result, adverse effects on the surrounding environment are reduced.

  As in the first embodiment, the counterpart transceiver receives the signal, and at that time, the original signal can be easily extracted.

  Similar to the first embodiment, during the reception period, a signal corresponding to the signal from the counterpart transceiver is applied between the electrodes.

  The transmission / reception circuit 3 instructs reception by the transmission / reception switching signal 31 during the reception period. Thereby, electric power is supplied to each solenoid S of the DC superimposing circuit 4 in the reception period. The switch 44 connects one end 21 </ b> A of the first transmission line 21 to the other electrode 42 </ b> B of the DC power supply 42. The switch 45 connects the first conductor 51 to the other end 43 </ b> B of the capacitance 43.

  Thereby, direct current is superimposed on a signal between one end 21A of the first transmission line 21 and one end 22A of the second transmission line 22 in the reception period.

  In the reception period, a signal on which the direct current is superimposed is supplied to each solenoid S of the level adjustment circuit 13. The direct current has sufficient energy to move the movable core of each solenoid S. Accordingly, the switch 133 connects the first electrode 11 to the first input terminal 132A of the differential amplifier 132. The switch 136 connects the other end 21 </ b> B of the first transmission line 21 to the other end 135 </ b> B of the capacitance 135. The switch 134 connects the other end 21 </ b> B of the first transmission line 21 to the other end of the inductor 137. The inductor 137 passes only the direct current in the signal, and the direct current is supplied to the differential amplifier 132 as a power source.

  Thereby, the signal generated between the electrodes is amplified by the differential amplifier 132, and the amplified signal is applied between the one end 21 </ b> A of the first transmission line 21 and the one end 22 </ b> A of the second transmission line 22. When the signal propagates through the signal cable 2, noise enters the signal cable 2, but since the level adjustment circuit 13 amplifies the signal, the SN ratio in the signal cable 2 is large.

  The transmission / reception circuit 3 receives the signal via the DC superimposing circuit 4. The signal-to-noise ratio in the signal cable 2 is large, and the transmission / reception circuit 3 can easily extract the original signal.

  As described above, the transceiver according to the second embodiment includes the first electrode 11 and the second electrode 12, the first transmission line 21 and the second transmission line 22, the first conductor 51 and the second conductor 52. A transmission / reception circuit 3 that applies a signal between the first conductor 51 and the second conductor 52 in the transmission period and receives a signal between the first conductor 51 and the second conductor 52 in the reception period; and a transmission period , DC is superimposed on the signal between the first conductor 51 and the second conductor 52 and applied between the one end 21A of the first transmission line 21 and the one end 22A of the second transmission line 22, DC superimposing circuit 4 for applying a signal between one end 21A, 22A between first conductor 51 and second conductor 52, and the other end 21B of first transmission line 21 and second transmission line 22 in the transmission period Attenuate the signal between the other end 22B Level adjustment circuit that is applied between the first electrode 11 and the second electrode 12 and amplifies the signal between the first electrode 11 and the second electrode 12 and applies it between the other ends 21B and 22B during the reception period. 13.

  Specifically, the second electrode 12 and the other end 22B of the second transmission line 22 are connected to each other, and the level adjustment circuit 13 has one end connected to the power terminals of the attenuator 131, the differential amplifier 132, and the differential amplifier 132. An inductor 137, a switch 133 that connects the first electrode 11 to one end 131A of the attenuator 131 or the first input terminal 132A of the differential amplifier 132, and the other end 21B of the first transmission line 21 to the other end of the attenuator 131. A switch 134 connected to the other end of 131B or the inductor 137, a capacitance 135 having one end 135A connected to the output terminal of the differential amplifier 132, and the other end 21B of the first transmission line 21 to the other end 135B of the capacitance 135 And a switch 136 for connecting to or disconnecting from the second conductor 52. One end 21A of the second transmission line 22 is connected to each other, and the DC superimposing circuit 4 includes a conductor 41 and a DC power source 42, and a capacitance 43 having one end 43A connected to one electrode 42A of the DC power source 42; A switch 44 for connecting one end 21A of the first transmission line 21 to the other electrode 42B or the conductor 41 of the DC power source 42 and a switch 45 for connecting the first conductor 51 to the other end 43B of the capacitance 43 or the conductor 41 are provided. .

  Therefore, the SN ratio in the signal cable 2 can be increased in the transmission period and the reception period, and as a result, the influence of noise can be reduced. Further, since the direct current of the signal is superimposed and this direct current is used as a power source in the level adjustment circuit 13, it is necessary to provide a battery in the level adjustment circuit 13 or supply power separately to the level adjustment circuit 13. For example, it is suitable when the signal cable 2 is lengthened.

DESCRIPTION OF SYMBOLS 1 ... External electrode part 2 ... Signal cable 3 ... Transmission / reception circuit 4 ... DC superposition circuit 11 ... 1st electrode 12 ... 2nd electrode 13 ... Level adjustment circuit 21 ... 1st transmission line 21A ... One end of 1st transmission line 21 21B: The other end of the first transmission line 21 22: The second transmission line 22A: One end of the second transmission line 22B ... The other end of the second transmission line 31 31: Transmission / reception switching signal 41 ... Conductor 42 ... DC power supply 42A ... one electrode 42B of the DC power supply 42 ... the other electrode 43 of the DC power supply 42 ... capacitance 43A ... one end of capacitance 43B ... the other end of capacitance 44, 45, 133, 134, 136 ... switch 51 ... first conductor 52 ... Second conductor 131 ... Attenuator 131A ... One end 131B of the attenuator 131 ... The other end 132 of the attenuator 131 ... Differential amplification 132A ... other end 137 ... inductor one end 135B ... capacitance 135 of the second input terminal 135 ... capacitance 135A ... capacitance 135 of the first input terminal 132B ... differential amplifier 132 of the differential amplifier 132

Claims (4)

A first electrode and a second electrode;
A first transmission line and a second transmission line;
A transmission / reception circuit that applies a signal between one end of the first transmission line and one end of the second transmission line in a transmission period and receives a signal between the one end in a reception period;
In the transmission period, the signal between the other end of the first transmission line and the other end of the second transmission line is attenuated and applied between the first electrode and the second electrode. In the reception period, the first electrode And a level adjustment circuit that amplifies a signal between the second electrode and applies the signal between the other end. The second electrode and the other end of the second transmission line are connected to each other;
The level adjustment circuit includes:
An attenuator and a differential amplifier;
A switch connecting the first electrode to one end of the attenuator or the first input terminal of the differential amplifier;
A switch for connecting or disconnecting the other end of the first transmission line to the other end of the attenuator;
A capacitance having one end connected to the output terminal of the differential amplifier;
The transceiver according to claim 1, further comprising: a switch that connects or disconnects the other end of the first transmission line to the other end of the capacitance. A first electrode and a second electrode;
A first transmission line and a second transmission line;
A first conductor and a second conductor;
A transmission / reception circuit that applies a signal between the first conductor and the second conductor in a transmission period and receives a signal between the first conductor and the second conductor in a reception period;
In the transmission period, a direct current is superimposed on the signal between the first conductor and the second conductor and applied between one end of the first transmission line and one end of the second transmission line. A DC superposition circuit for applying a signal between the ends between the first conductor and the second conductor;
In the transmission period, the signal between the other end of the first transmission line and the other end of the second transmission line is attenuated and applied between the first electrode and the second electrode. In the reception period, the first electrode And a level adjustment circuit for amplifying a signal between the second electrode and applying the signal between the other end. The second electrode and the other end of the second transmission line are connected to each other;
The level adjustment circuit includes:
An attenuator, a differential amplifier, and an inductor having one end connected to a power supply terminal of the differential amplifier;
A switch connecting the first electrode to one end of the attenuator or the first input terminal of the differential amplifier;
A switch connecting the other end of the first transmission line to the other end of the attenuator or the other end of the inductor;
A capacitance having one end connected to the output terminal of the differential amplifier;
A switch for connecting or disconnecting the other end of the first transmission line to the other end of the capacitance;
The second conductor and one end of the second transmission line are connected to each other,
The DC superimposing circuit is
A conductor and a DC power source;
A capacitance having one end connected to one electrode of the DC power supply;
A switch for connecting one end of the first transmission line to the other electrode of the DC power supply or the conductor;
The transceiver according to claim 3, further comprising: a switch that connects the first conductor to the other end of the capacitance or to the conductor.

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