JP2006165690A - Electric field communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric field communication system capable of turning off a power supply of a transmission/reception section when no data are transceived thereby to be capable of reducing the power consumption. <P>SOLUTION: The communication system comprises a combination of a first electric field communication transceiver and a second electric field communication transceiver each respectively provided with a transmission section and a reception section in order to make communication, the first electric field communication transceiver includes: a storage means for storing received data by a predetermined capacity; and a processing means for requesting the second electric field communication transceiver to transmit data when the data amount of the data stored in the storage means is less than a prescribed capacity, and the second electric field communication transceiver includes a data storage means for storing the data in a way capable of outputting the data in response to the request from the processing means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electric field communication system that induces an electric field in an electric field transmission medium and transmits information using the induced electric field.

  Due to the miniaturization and high performance of portable terminals, wearable computers that can be attached to living bodies have been attracting attention. Conventionally, as information communication between such wearable computers, an electric field communication system is connected to a computer and configured integrally, and an electric field induced by the electric field communication system is transmitted to the inside of a living body that is an electric field transmission medium. A method of transmitting and receiving information has been proposed (see, for example, Patent Document 1).

  In such an electric field communication system for electric field communication floating from the earth ground, a variable reactance is inserted between the transmission / reception electrode and the transmission circuit in order to efficiently induce an electric field in the human body, and the human body, the circuit ground, and the earth ground. The resonance phenomenon with the stray capacitance between them is used. In order to bring the variable reactance into a resonance state, the reactance value is adjusted using an amplitude monitor unit, a control signal generation unit, an electric field detection optical unit, and a signal processing unit.

  In addition, when the transceiver 1 is combined with the portable audio player 3 as shown in FIG. 4 and the electric field communication system via the human body 5 is applied, it is necessary to use a battery with a small capacity in order to lighten the device on the headphone 4 side. There is. For this purpose, it is necessary to reduce the power consumption of the electric field communication transceiver 2 on the headphone 4 side.

In this case, the transceiver 2 on the headphone 4 side and the transceiver 1 on the portable audio player 3 side turn on the power of the transmission unit and / or the reception unit even when data is not being transmitted / received.
JP 2004-153708 A

  In the electric field communication system according to the above-described prior art, even when data is not being transmitted / received, it is necessary to turn on the power of the transmission unit, the reception unit, or both, which increases power consumption. It was.

  The present invention has been made in view of the above-described problems. The object of the present invention is to turn off the power of the transmission / reception unit when data is not being transmitted / received, thereby reducing power consumption. An object of the present invention is to provide an electric field communication system that can be reduced.

  In order to solve the problem, the present invention according to claim 1 induces an electric field based on data to be transmitted in an electric field transmission medium, and transmits the data using the induced electric field, while the electric field is transmitted. An electric field communication system for communicating with each other between transceivers having a configuration for receiving the data by receiving an electric field based on the data to be received induced in a transmission medium, wherein the communication system includes: The first electric field communication transceiver comprises a combination of a first electric field communication transceiver and a second electric field communication transceiver each having a transmission unit and a reception unit to perform the communication, and the first electric field communication transceiver transmits the received data Storage means for storing in a predetermined capacity set in advance, and the data amount of the data stored in the storage section is less than the predetermined capacity A processing means for requesting the second electric field communication transceiver to transmit the data, wherein the second electric field communication transceiver can output the data in response to a request from the processing unit. The data storage means is stored.

  The present invention according to claim 2 provides the second electric field communication transceiver according to claim 1, wherein the second electric field communication transceiver turns off the power supply to the receiving unit only at the time of reactance adjustment and transmission of the data in the transmitting unit. And control means for controlling the power supply to the transmission unit to be ON only when reactance adjustment is performed in the transmission unit and when the data is transmitted.

  According to a third aspect of the present invention, in any one of the first and second aspects, the first electric field communication transceiver requests the second electric field communication transceiver to transmit the data. When transmitting the transmission request signal, variable reactance means for sequentially selecting the reactance value from a plurality of preset reactance values is provided.

  According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, the processing means causes the first electric field communication transceiver to transmit the data to the second electric field communication transceiver. After transmitting a transmission request signal for requesting, if the data is not received even after a predetermined time has elapsed, control for retransmitting the transmission request signal is executed.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the processing means allows the first electric field communication transceiver to transmit the data to the second electric field communication transceiver. After transmitting the transmission request signal for requesting, when the data amount of the data stored in the storage means is not received until it becomes 0, the power supply to the transmission unit and the reception unit is turned off. Execute control to

  ADVANTAGE OF THE INVENTION According to this invention, the power supply of a transmission / reception part can be turned off when not transmitting / receiving data, Therefore The electric field communication system which can reduce power consumption can be provided.

  FIG. 1 is a configuration diagram for explaining the overall configuration according to the embodiment of the electric field communication system of the present invention. Here, for the description of the embodiment of the present invention, the configuration of the portable audio player already shown in FIG. 4 is referred to.

  In FIG. 1, a living body 5 such as a human body, a first electric field communication transceiver 2, a second electric field communication transceiver 1, and data recorded on a recording medium such as a CD, MD, or MP3 are reproduced. A player (data storage means) 3, a headphone 4 that reproduces data reproduced by the player 3 as sound, a processing section (processing means) 30, a storage section (storage means) 31, and a living body 5 are first described. A transmission / reception electrode 26 and an insulator 27 interposed between the electric field communication transceiver 2 and the second electric field communication transceiver 1 are shown.

  Further, the second electric field communication transceiver 1 includes a receiving unit 6 and a transmitting unit 7. The receiving unit 6 includes an electric field detection optical unit / signal processing unit 10, a switch A 11, a demodulation circuit 12, and a waveform shaping unit 13. The transmission unit 7 includes a transmission circuit 17, a switch B 16, a variable reactance unit 15, and a control unit 14.

  Further, the first electric field communication transceiver 2 includes a reception unit 8 and a transmission unit 9 as in the second electric field communication transceiver 2. The reception unit 8 includes an electric field detection optical unit / signal processing unit 20, a demodulation circuit 21, and a waveform shaping unit 22. The transmission unit 9 includes a transmission circuit 23, a switch C24, and a variable reactance unit 25.

  The difference in configuration between the first electric field communication transceiver 2 and the second electric field communication transceiver 1 is that, in the second electric field communication transceiver 1, the receiving unit 6 includes a switch A11, and the transmission unit 7 includes a control unit 14 ( Control means).

  In such a configuration, in the player 3, after adjusting the variable reactance unit 15, the data f 2 is output from the player 3 to the transmission unit 7 of the second transceiver 1, and the data f 2 modulated by the transmission circuit 17 is supplied to the living body 5. Send. At the time of reactance adjustment, a1 and b1 of the switch A11 and the switch B16 are connected, and the reactance value in the variable reactance unit 15 is appropriately adjusted by the control unit 14 while monitoring the electric field induced in the living body.

  In the headphone 4, the switch C24 is opened to stop the transmission of the transmission unit 9, the electric field detection optical unit / signal processing unit 20 detects the electric field induced in the living body 5, and the demodulation circuit 21 reproduces the data f2. , Output to the processing unit 30. The processing unit 30 temporarily stores the input data f2 in the storage unit 31 and then outputs the data f2 to the headphones 4 as appropriate.

  Next, in FIG. 2, the operation of the first electric field communication transceiver 2 combined with the headphone 4 according to the embodiment of the electric field communication system of the present invention will be described with reference to a flowchart.

  First, the player 3 is turned on and the reproduction of the data f2 is started (step 1: S1).

  Next, whether or not the data amount n stored in the storage unit (storage device) 31 is “storage device data amount n> Nt” with respect to a predetermined prescribed data amount Nt (Yes / No) ) Will continue to be monitored. In this monitoring, as long as the relationship of “storage device data amount n> Nt” is satisfied (Yes), reproduction of the data f2 by the player 3 proceeds (step 2: S2).

  Further, reproduction of the data f2 by the player 3 progresses, and it is confirmed that “storage device data amount n <Nt” is satisfied (No), and when the data amount becomes smaller than a preset predetermined data amount Nt, the headphones 4 The transmitter 9 is turned on, and a transmission request signal f1 of data f2 is transmitted to the second electric field communication transceiver 1 of the player 3. At the same time as this transmission is executed, a timer (not shown) starts timing (t1 = 0). Thereafter, the transmitter 9 is turned off and the receiver 8 is turned on to wait for the data f2 to be transmitted from the player 3 (step 3: S3).

  The variable reactance unit 25 of the transmission unit 9 of the headphone 4 transmits the transmission request signal f1 while sequentially changing to a preset value without adjustment by feedback control. This eliminates the need for a control unit for controlling the variable reactance unit 25 and reduces the circuit scale of the transmission unit 9 on the headphone 4 side.

  After receiving the transmission request signal f1 on the player 3 side, the data f2 is transmitted to the headphone 4 side, and the presence or absence of reception is determined by the first electric field communication transceiver 1 on the headphone 4 side (Yes / No) (step 4). : S4).

  The power supply of the receiving unit 6 included in the second electric field communication transceiver 1 on the player 3 side is turned off at the time of reactance adjustment in the variable reactance unit 15 of the transmission unit 7 and at the time of transmission of the data f2 by the transmission circuit 17, otherwise Leave on. The transmission unit 7 on the player 3 side is turned on only at the time of reactance adjustment in the variable reactance unit 15 of the transmission unit 7 and at the time of transmission of the data f 2 by the transmission circuit 17. When the data f2 is received within a predetermined period (T1) set in advance in the time measurement already started after the transmission request signal f1 of the data f2 is transmitted on the headphone 4 side (step 5: S5), The received data f2 is stored in the storage unit 31, and the power supply of the receiving unit 8 is turned off (step 8: S8).

  On the other hand, if the data f2 is not received within the period T1 in step 5: S5 (t1 <T1), the power of the receiving unit 8 is once turned off (step 6: S6) and then the power of the transmitting unit 9 is turned on. Is turned on and the transmission request signal f1 is transmitted again.

  Further, when the data f2 is not received until the data f2 stored in the storage unit 31 becomes “0” (step 7: S7), it is assumed that the player 3 is not connected, and the first electric field communication transceiver 2 is turned off (step 9: S9).

  The processing unit 30 performs a process of outputting the data f2 in the storage unit 31 to the headphones 4 in parallel with this process. By performing such processing, the first electric field communication transceiver 2 on the headphone 4 side turns on the power supply of the first electric field communication transceiver 2 only when there is a request for data f2, so that the substantial consumption is reduced. Electric power can be reduced.

  Next, FIG. 3 shows an explanatory diagram for explaining the carrier frequency according to the embodiment of the electric field communication system of the present invention.

  As shown in FIG. 3, when an electric field is induced in the living body 5 that is an electric field transmission medium from the transceiver 35 floating from the ground, a reactance X41 is inserted on the transmission side, and the stray capacitance Cb38 between the living body 5 and the ground is inserted. Further, by resonating with the stray capacitance Cg37 between the ground of the transceiver 35 and the ground, the induced electric field can be increased. Vb39, which is a voltage between the living body 5 and the ground ground in this resonance state, is expressed by the following equation.

(Formula) ... Vb = Vs / (2πfRsCb)
Here, the signal source Vs43 and the resistor Rs42 are the voltage amplitude (Vs) and the output resistance (Rs) of the signal source provided in the transceiver 35, respectively, f is the carrier frequency of the transceiver 35, and Cb38 is between the living body 5 and the ground. It is a stray capacitance.

  From the above equation, Vb39, which is proportional to the induced electric field, increases as the carrier frequency f is lower. As the carrier frequency f decreases, the amount of information (bit rate) that can be transmitted per unit time decreases. For this reason, in a communication system where the bit rate may be low, a method of increasing Vb39 by lowering the carrier frequency f can be used. If Vb39 becomes large, the light quantity (current) of a laser (not shown) of the electric field detection optical unit can be reduced on the receiving side, and thus the power consumption can be reduced. Further, if the carrier frequency f is reduced, the power consumption required for signal processing by the electronic circuit in the transmission / reception unit can also be reduced.

  In transmission from the first electric field communication transceiver 2 on the headphone 4 side with a relatively small amount of information to be transmitted to the second electric field communication transceiver 1 on the player 3 side, the transmission unit on the headphone 4 side is reduced by lowering the carrier frequency f. 9 and the receiving unit 6 on the player 3 side can be reduced in power consumption. The receiving unit 6 on the player 3 side is turned on not only while receiving the signal on the headphone 4 side but also while waiting for the signal on the headphone 4 side to come. For this reason, the substantial power consumption of the entire electric field communication system can be reduced by reducing the power consumption of the receiving unit 6 on the player 3 side.

  In the present embodiment, the portable audio player for music is taken as an example for the player 3, but the electric field communication system of the present invention can also be applied to a device (for example, a head mounted display) that displays images.

  In the configuration of the embodiment of the present invention described above, an electric field based on data to be transmitted is induced in the electric field transmission medium, and data is transmitted using the induced electric field, while the electric field transmission medium is induced. An electric field communication system for communicating with each other between transceivers configured to receive data by receiving an electric field based on data to be received. The communication system includes a transmission unit and a reception unit, respectively. The first electric field communication transceiver comprises a combination of the first electric field communication transceiver and the second electric field communication transceiver, and performs communication, and the first electric field communication transceiver stores the received data with a predetermined capacity set in advance. And the second electric field communication transceiver when the data amount of the data stored in the storage unit and the storage unit is less than a predetermined capacity. And a processing means for requesting the second field communication transceiver includes a data storage unit storing an output enable in response to a request from the processing unit data.

  Further, the second electric field communication transceiver turns off the power supply to the receiving unit only at the time of reactance adjustment and data transmission in the transmission unit, and the power supply to the transmission unit at the time of reactance adjustment and data transmission in the transmission unit Control means for only turning on is provided.

  The first electric field communication transceiver sequentially transmits reactance requests from among a plurality of preset reactance values when transmitting a transmission request signal for requesting data transmission to the second electric field communication transceiver. Variable reactance means for selecting a value are provided.

  The processing means transmits the data even if a predetermined time elapses after the first electric field communication transceiver transmits a transmission request signal for requesting data transmission to the second electric field communication transceiver. When the signal is not received, control for retransmitting the transmission request signal is executed.

  Further, the processing means transmits the transmission request signal for requesting the second electric field communication transceiver to transmit data to the second electric field communication transceiver, and then the data amount of the data stored in the storage means is In the case where the signal is not received until 0, control for turning off the power supply to the transmission unit and the reception unit is executed.

  In addition, according to the present embodiment described above, the electric field communication system that can turn off the power of the transmission / reception unit when data is not being transmitted / received, thereby reducing power consumption. Can be provided.

The block diagram for demonstrating the whole structure based on embodiment of the electric field communication system of this invention is shown. FIG. 2 is a flowchart for explaining the operation according to the embodiment of the electric field communication system of the present invention. The explanatory view for explaining the carrier frequency concerning the embodiment of the electric field communication system of the present invention is shown. 1 shows a configuration of a portable audio player using a conventional transceiver.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 2nd electric field communication transceiver 2 1st electric field communication transceiver 3 Player 4 Headphone 5 Living body 6, 8 Reception part 7, 9 Transmission part 10, 20 Electric field detection optical part and signal processing part 11 Switch A
12, 21 Demodulation circuit 13, 22 Waveform shaping unit 14 Control unit 15, 25 Variable reactance unit 16 Switch B
17, 23 Transmission circuit 20 Sampling circuit 22 Logic circuit 24 Switch C
26 Transceiver Electrode 27 Insulator 30 Processing Unit 31 Storage Unit 35 Transceiver Transmitter Model 36 Transceiver Ground 37 Floating Capacitance Cg Between Transceiver Ground and Ground
38 Stray capacitance Cb between living body and ground
39 Potential difference Vb
40 Transmitting electrode 41 Reactance X
42 Resistance Rs
43 Signal source Vs

Claims (5)

An electric field based on data to be transmitted is induced in the electric field transmission medium, and the data is transmitted using the induced electric field, while an electric field based on the data to be received induced in the electric field transmission medium is received. An electric field communication system for communicating with each other between transceivers having a configuration for receiving the data,
The communication system is configured by a combination of a first electric field communication transceiver and a second electric field communication transceiver each including a transmission unit and a reception unit, and performs the communication.
The first electric field communication transceiver comprises:
Storage means for storing the received data in a predetermined capacity set in advance;
Processing means for requesting the second electric field communication transceiver to transmit the data when the data amount of the data stored in the storage unit is less than the predetermined capacity;
The second electric field communication transceiver comprises:
An electric field communication system comprising data storage means for storing the data so as to be output in response to a request from the processing unit. The second electric field communication transceiver comprises:
Turn off the power supply to the receiving unit only at the time of reactance adjustment and transmission of the data in the transmitting unit,
2. The electric field communication system according to claim 1, further comprising a control unit configured to control power supply to the transmission unit to be ON only when reactance adjustment is performed in the transmission unit and when the data is transmitted. The first electric field communication transceiver comprises:
A variable for sequentially selecting the reactance value from a plurality of preset reactance values when transmitting a transmission request signal for requesting transmission of the data to the second electric field communication transceiver 3. The electric field communication system according to claim 1, further comprising reactance means. The processing means includes
After the first electric field communication transceiver transmits a transmission request signal for requesting transmission of the data to the second electric field communication transceiver, the data is received even if a predetermined time elapses. The electric field communication system according to claim 1, wherein control for retransmitting the transmission request signal is executed when the transmission request signal is not transmitted. The processing means includes
After the first electric field communication transceiver transmits a transmission request signal for requesting transmission of the data to the second electric field communication transceiver, the data amount of the data stored in the storage unit is 0. 5. The electric field communication system according to claim 1, wherein control is performed to turn off power supply to the transmission unit and the reception unit in a case where the signal is not received until.

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