JP2014075670A - Information transfer system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an information transfer system in which a transmission side device mounted on an organism is reduced in size.SOLUTION: An information transfer system (1) performs information transfer between a transmitter (11) and a receiver (12) by a carrier transferred via an organism (2). The transmitter includes a transmitting electrode (111) disposed to face the surface of the organism and transmitting the carrier, and the receiver includes a receiving electrode (121) receiving the carrier transmitted via the organism and a detector (124) detecting an amplitude change of the carrier received from the organism in a transmission process.

Description

  The present invention relates to an information transmission system that transmits information via a living body such as a human body, and more particularly to an information transmission system that can transmit biological information such as a heart rate.

  A system has been proposed in which biological information such as a heart rate is detected by a sensor and transmitted to an external data processing apparatus via the living body (see, for example, Patent Document 1). The system includes a transmitter connected to the sensor and a receiver that receives a signal from the transmitter. The transmitter modulates a carrier wave based on biological information from the sensor, and applies a corresponding electric field (electromagnetic field) to the living body. The receiver receives a carrier wave transmitted through a living body and demodulates biological information in the carrier wave. The demodulated biological information is processed by a data processing device provided at the subsequent stage of the receiver. In this system, since the transmitter and the receiver are not connected by wire, the movement of the wearer is not limited by the connection wiring.

JP 2006-271798 A

  By the way, in the above-described system, in order to modulate the carrier wave based on the biological information detected by the sensor, the transmitting-side apparatus includes a sensor for detecting biological information and a modulation circuit for modulating the carrier wave. I need it. However, if a sensor and a modulation circuit are provided in the transmission-side device, the transmission-side device worn on the living body becomes large, and the burden on the wearer increases.

  The present invention has been made in view of this point, and an object of the present invention is to provide an information transmission system in which a transmission-side device attached to a living body is miniaturized.

  The information transmission system of the present invention is an information transmission system that transmits information between a transmitter and a receiver by a carrier wave transmitted through a living body, and the transmitter faces the surface of the living body. A transmitter electrode arranged to transmit the carrier wave; the receiver receiving the carrier wave transmitted through the living body; and an amplitude change of the carrier wave received from the living body in the course of transmission And a detection unit for detecting.

  According to this configuration, the biological information can be detected by using the amplitude change of the carrier wave received from the living body in the process of transmission. Therefore, the transmitter for detecting the biological information and the modulation circuit for modulating the carrier wave are provided. There is no need to provide it on the side. As a result, an information transmission system in which a transmission-side device attached to a living body is miniaturized can be provided.

  The information transmission system of this invention WHEREIN: It is preferable that the said detection part acquires the biological information of the said biological body from the amplitude change of the said carrier wave.

  In the information transmission system of the present invention, the transmission electrode may be disposed in proximity to the chest of the living body, and the detection unit may acquire the heart rate information of the living body from a change in amplitude of the carrier wave. According to this configuration, since the transmitting electrode is arranged in a portion that is easily affected by the heartbeat, the amplitude of the carrier wave is changed according to the heartbeat. As a result, heart rate information such as heart rate can be acquired in the detection unit.

  In the information transmission system of the present invention, the transmitter may include a storage unit in which identification information is stored, and the identification information may be transmitted by the carrier wave. According to this configuration, it is possible to manage the heartbeat information obtained in the detection unit in correspondence with the identification information.

  In the information transmission system of the present invention, the receiver may include a band-pass filter for extracting the identification information and a low-pass filter for extracting the heartbeat information. According to this configuration, identification information and heartbeat information can be appropriately extracted from the carrier wave.

  In the information transmission system of the present invention, the transmission electrode may have an area where a capacitance capable of detecting the heartbeat information is obtained. According to this configuration, the heart rate information of the living body can be acquired appropriately.

  According to the present invention, it is possible to provide an information transmission system in which a transmission-side device attached to a living body is downsized.

It is a schematic diagram which shows the structural example of the information transmission system which concerns on this Embodiment. It is a schematic diagram which shows the specific structural example of a transmitter. It is a circuit diagram which shows the specific structural example of AM detection circuit. It is a graph which shows the signal output from a receiver in an information transmission system. It is a schematic diagram which shows the relationship between an electrostatic capacitance and an electrode area. It is a table which shows the relationship between an electrode area and the detection condition of heart rate information.

  Hereinafter, a configuration of an information transmission system according to an embodiment of the present invention will be described with reference to the drawings. In the following, an information transmission system capable of acquiring heart rate information such as heart rate will be described. However, the information transmission system of the present invention can also be used to acquire biological information other than heart rate information. In the present embodiment, a simplified information transmission system will be described for convenience of explanation, but the configuration necessary for the information transmission system is provided without a shortage.

  FIG. 1 is a schematic diagram illustrating a configuration example of an information transmission system according to the present embodiment. The information transmission system 1 includes a transmitter 11 that generates a high-frequency signal as a carrier wave, and a receiver 12 that receives the carrier wave transmitted from the transmitter 11 via a living body 2 such as a human body. The carrier wave transmitted from the transmitter 11 is received by the receiver 12 via the living body 2. The receiver 12 acquires biological information from a carrier wave transmitted via the living body 2 and sends it to the data processing device 13 at the subsequent stage.

  The transmitter 11 is configured to be mountable near the chest of the living body 2. FIG. 2 is a schematic diagram illustrating a specific configuration example of the transmitter. As shown in FIG. 2, the transmitter 11 includes a living body side electrode (transmission electrode) 111 facing the surface of the living body 2 and a ground electrode 112 spaced from the living body side electrode 111. The transmitter 11 includes a storage circuit (storage unit) 113 in which identification information unique to the transmitter 11 is stored.

  The living body side electrode 111 is formed in a flat plate shape and has a predetermined area so as to be appropriately capacitively coupled to the living body 2. The living body side electrode 111 applies a high frequency electric field corresponding to a carrier wave to the living body 2. The living body side electrode 111 is disposed close to the chest of the living body 2 so that the carrier wave is easily affected by the movement of the heart. In this arrangement, the state of the transmission path is changed according to the movement of the heart, so that the amplitude of the carrier wave is changed according to the movement of the heart in the process of transmission through the living body 2. That is, the change in the amplitude of the carrier wave corresponds to heartbeat information indicating the movement of the heart of the living body 2. The living body side electrode 111 is only required to be capacitively coupled to the living body 2 and does not need to be in contact with the living body 2. For example, the living body side electrode 111 and the living body 2 may be capacitively coupled through clothing or the like.

  The ground electrode 112 is formed in a flat plate shape similar to the living body side electrode 111 and is capacitively coupled to a constant potential source such as the ground. The ground electrode 112 generates a ground potential used for transmitting a carrier wave. Note that the capacitive coupling target of the ground electrode 112 may not be the ground as long as a substantially constant ground potential can be generated. For example, the ground electrode 112 may be capacitively coupled to a building or a vehicle.

  The storage circuit 113 stores identification information unique to the transmitter 11 (or the wearer). The carrier wave is modulated based on the identification information and transmitted to the receiver 12 via the living body 2. With this identification information, it is possible to manage the heartbeat information obtained as an amplitude change in the process of transmitting the living body 2 in correspondence with the identification information.

  The receiver 12 includes a reception electrode 121 that receives a signal corresponding to an electric field generated in the living body 2, a bandpass filter 122 that passes a predetermined frequency band in the reception signal received by the reception electrode 121, and a bandpass filter An amplifier 123 that amplifies the signal that has passed through 122, an AM detection circuit (detection unit) 124 that detects a change in the amplitude of the signal, and a low-pass filter 125 that passes through a low frequency band in the signal detected by the AM detection circuit 124. And a band stop filter 126 that removes a predetermined frequency band from the signal that has passed through the low-pass filter 125.

  The receiving electrode 121 receives a signal corresponding to the electric field generated in the living body 2 by being in contact with the living body 2. Since the high frequency electric field corresponding to the carrier wave is applied to the living body 2 from the living body side electrode 111, the receiving electrode 121 can receive a signal including the carrier wave transmitted from the transmitter 11. The reception signal received by the reception electrode 121 is input to the subsequent band-pass filter 122.

  The band pass filter 122 passes a predetermined frequency band in the input received signal. The pass band of the band pass filter 122 is set corresponding to the frequency of the carrier wave generated by the transmitter 11. For this reason, the carrier wave in the received signal is passed and other frequency components are removed. Thus, the signal including the carrier wave that has passed through the bandpass filter 122 includes identification information transmitted from the transmitter and heart rate information obtained as an amplitude change in the process of transmission through the living body 2. . The signal including the carrier wave that has passed through the band pass filter 122 is amplified by the amplifier 123 and then input to the AM detection circuit 124.

  The AM detection circuit 124 detects an amplitude change by envelope detection of a signal including an input carrier wave. The amplitude of the carrier wave is changed according to the movement of the heart in the process of transmission through the living body 2. The carrier wave is modulated according to the identification information. For this reason, by detecting the amplitude change of the signal including the carrier wave by the AM detection circuit 124, it is possible to obtain a signal including heartbeat information and identification information indicating the motion of the heart of the living body 2.

  FIG. 3 is a circuit diagram showing a specific configuration example of the AM detection circuit. The AM detection circuit 124 shown in FIG. 3 includes two diodes D1 and D2 and one capacitor C1. On the input side of the AM detection circuit 124, the anode of the diode D1 and the cathode of the diode D2 are connected. On the other hand, on the output side of the AM detection circuit 124, the cathode of the diode D1 and one terminal of the capacitor C1 are connected. The anode of the diode D2 and the other terminal of the capacitor C1 are grounded. The AM detection circuit 124 is not limited to the configuration shown in FIG.

  A signal corresponding to a change in the amplitude of the carrier wave detected by the AM detection circuit 124 is input to the low-pass filter 125. Here, the signal detected by the AM detection circuit 124 includes identification information of a relatively high frequency component in addition to the heartbeat information. Therefore, in order to extract only heartbeat information from the carrier wave, a signal having a relatively high frequency component is removed by the low-pass filter 125. The cut-off frequency of the low-pass filter 125 is set within a range in which heartbeat information can be appropriately extracted. The signal that has passed through the low-pass filter 125 is input to the band stop filter 126.

  The band stop filter 126 is a notch filter, for example, and attenuates a predetermined frequency component in the input signal. A signal that has passed through the low-pass filter 125 may include noise at a frequency (for example, noise of 50 Hz or 60 Hz) due to the power supply. Therefore, the noise caused by the power source is removed by the band stop filter 126. A signal corresponding to the heartbeat information that has passed through the band stop filter 126 is sent to the data processing device 13 for various processing.

  Next, an outline of the operation of the information transmission system 1 will be described. The carrier wave modulated based on the identification information stored in the memory circuit 113 of the transmitter 11 is applied to the living body 2 from the living body side electrode 111 as a high frequency electric field. The carrier wave applied to the living body 2 is affected by the movement of the heart in the process of transmitting through the living body 2, and the amplitude is changed according to the movement of the heart.

  The high frequency electric field generated in the living body 2 is received by the receiving electrode 121 of the receiver 12. A reception signal including a carrier wave received by the reception electrode 121 is input to the AM detection circuit 124 after passing through the band-pass filter 122. The AM detection circuit 124 detects heartbeat information and identification information indicating the motion of the heart of the living body 2 by performing envelope detection on the signal including the input carrier wave.

  The signal detected by the AM detection circuit 124 is input to the low-pass filter 125, and heart rate information is extracted. The signal that has passed through the low-pass filter 125 is sent to the data processing device 13 via the band stop filter 126. The data processing device 13 performs various data processing based on the heartbeat information and the identification information.

  FIG. 4 is a graph showing a signal output from the receiver in the information transmission system. 4A shows a signal output from the receiver 12 of the present embodiment, and FIG. 4B shows a signal output from the receiver of the comparative example. The difference between the present embodiment and the comparative example is the area of the living body side electrode. Specifically, the living body side electrode 111 of the present embodiment has an area (30 mm × 30 mm) suitable for detecting heart rate information, but the living body side electrode (10 mm × 5 mm) of the comparative example has heart rate information. Does not have an area suitable for detection.

  As shown in FIG. 4A, since the living body side electrode 111 of the present embodiment has an area suitable for detecting heartbeat information, a regular pulse signal corresponding to the heartbeat is output as the output of the receiver 12. Has been obtained. On the other hand, as shown in FIG. 4B, since the living body side electrode of the comparative example does not have an area suitable for detecting heartbeat information, an irregular pulse signal is output from the receiver. Note that it is considered that the cause of the irregular pulse signal as shown in FIG. 4B is that the carrier wave is affected by the movement of the living body 2 other than the heart.

  FIG. 5 is a schematic diagram showing the relationship between capacitance and electrode area. 5A schematically shows a case where the areas of the living body side electrode 111 and the ground electrode 112 are relatively large, and FIG. 5B schematically shows a case where the areas of the living body side electrode 111 and the ground electrode 112 are relatively small. Yes. As shown in FIG. 5A, for example, when a capacitance of 100 pF is formed by the living body side electrode 111 and the ground electrode 112, the influence of the capacitance (about 1 to 2 pF) caused by the heart 21 is It is about 1-2%. On the other hand, as shown in FIG. 5B, for example, when a 10 pF capacitance is formed by the living body side electrode 111 and the ground electrode 112, the influence of the capacitance caused by the heart 21 is 10 to 10%. It will be about 20%.

  That is, the influence of the movement of the heart 21 on the carrier wave increases as the areas of the living body side electrode 111 and the ground electrode 112 become smaller, as shown in FIG. 5B. Therefore, in order to sufficiently detect heartbeat information, it is preferable that the areas of the living body side electrode 111 and the ground electrode 112 are not too large. However, when the electrode area is reduced, the influence of the movement of the other part of the living body 2 increases as in the case shown in FIG. 4B, and only the heartbeat information may not be detected properly. For this reason, it is preferable that the areas of the living body side electrode 111 and the ground electrode 112 have a certain size.

FIG. 6 is a table showing the relationship between the electrode area and the heartbeat information detection status. The living body side electrode and the ground electrode in the table indicate the area (mm ² ) of the living body side electrode and the ground electrode, respectively, and the electrode interval indicates the interval (mm) between the living body side electrode and the ground electrode. The capacitance change indicates a change value (pF) of the capacitance between the living body side electrode and the ground electrode, and the detection amplitude indicates the amplitude voltage (V) in the detected heartbeat information. Further, the mark of the detection status indicates that a regular pulse waveform accompanying the heartbeat appears in the output from the band stop filter 126, and the triangle mark indicates the movement of a part other than the heart in the regular pulse waveform associated with the heartbeat. This indicates that an irregular pulse that is considered to be an influence of the heartbeat is included, and the cross indicates that the pulse waveform accompanying the heartbeat cannot be read due to the irregular pulse. The frequency of the carrier wave was 10.7 MHz.

As shown in FIG. 6, when the areas of the living body side electrode and the ground electrode are both 30 × 30 (mm ² ), heartbeat information can be detected appropriately regardless of the electrode interval (see FIG. 4A). On the other hand, when the area of the living body side electrode and the ground electrode is reduced to 10 × 5 (mm ² ), heartbeat information cannot be detected properly (see FIG. 4B). When the area of the living body side electrode and the ground electrode is in the range of 20 × 5 (mm ² ) to 20 × 20 (mm ² ), heart rate information can be detected with a certain degree of accuracy.

In addition, when the area of the living body side electrode and the ground electrode is 20 × 5 (mm ² ) and the case of 10 × 10 (mm ² ), there is no great difference in the detection situation. From this, it can be seen that the detection situation mainly depends on the areas of the living body side electrode and the ground electrode. The living body side electrode 111 and the ground electrode 112 are preferably formed in an area where a capacitance capable of appropriately detecting heartbeat information is obtained.

  As described above, the information transmission system 1 according to the present embodiment can detect biological information such as heartbeat information using the amplitude change of the carrier wave received from the living body 2 during the transmission process. The transmitter 11 and the modulation circuit for modulating the carrier wave need not be provided on the transmitter 11 side. Thereby, the information transmission system 1 in which the transmission-side device attached to the living body is miniaturized can be provided.

  Further, in the information transmission system 1 according to the present embodiment, the living body side electrode (transmission electrode) 111 is disposed close to the chest of the living body 2 so that the carrier wave is easily affected by the heartbeat. In the AM detection circuit (detection unit) 124, heart rate information such as heart rate can be acquired. Further, the transmitter 11 includes a storage circuit (storage unit) 113 in which identification information is stored, and is configured so that the identification information is transmitted by a carrier wave. Therefore, the heartbeat information obtained in the AM detection circuit 124 is identified. It is possible to manage in correspondence with information.

  In addition, since the receiver 12 includes a bandpass filter 122 for extracting identification information and a low-pass filter 125 for extracting heartbeat information, the identification information and heartbeat information are appropriately extracted from the carrier wave. it can. Further, since the transmission electrode 111 has an area where a capacitance capable of detecting heartbeat information of the living body 2 is obtained, the heartbeat information of the living body 2 can be appropriately acquired.

  In addition, this invention is not limited to description of the said embodiment, It can implement by changing suitably in the aspect in which the effect is exhibited. For example, in the above embodiment, an information transmission system capable of acquiring heart rate information has been described. However, the information transmission system may be configured so that other biological information can be acquired. For example, by appropriately changing the area of the transmission electrode, it is possible to realize an information transmission system that can acquire biological information indicating a respiratory state.

  Moreover, in the said embodiment, although the information transmission system comprised supposing the human body as a detection target of biological information is shown, a biological body is not restricted to a human body. For example, an information transmission system may be configured to acquire biological information such as pets and livestock. In addition, the configurations of the transmitter and the receiver configuring the information transmission system can be changed as appropriate. For example, various filters of the receiver can be changed or omitted within a range that does not affect the operation.

  The information transmission system of the present invention is useful when acquiring biological information such as heartbeat information.

DESCRIPTION OF SYMBOLS 1 Information transmission system 2 Living body 11 Transmitter 12 Receiver 13 Data processing apparatus 21 Heart 111 Living body side electrode (transmission electrode)
112 Ground electrode 113 Memory circuit (memory part)
121 reception electrode 122 band-pass filter 123 amplifier 124 AM detection circuit (detection unit)
125 Low-pass filter 126 Band stop filter D1, D2 Diode C1 Capacitor

Claims (6)

An information transmission system for transmitting information between a transmitter and a receiver by a carrier wave transmitted through a living body,
The transmitter includes a transmission electrode that is arranged to face the surface of the living body and transmits the carrier wave,
The receiver includes a receiving electrode that receives the carrier wave transmitted through the living body, and a detection unit that detects a change in amplitude of the carrier wave received from the living body in the course of transmission. Information transmission system.   The information transmission system according to claim 1, wherein the detection unit acquires biological information of the living body from an amplitude change of the carrier wave. The transmitting electrode is disposed close to the chest of the living body;
The information transmission system according to claim 1, wherein the detection unit acquires heart rate information of the living body from an amplitude change of the carrier wave. The transmitter includes a storage unit in which identification information is stored,
4. The information transmission system according to claim 3, wherein the identification information is transmitted by the carrier wave.   The information transmission system according to claim 4, wherein the receiver includes a band-pass filter for extracting the identification information and a low-pass filter for extracting the heartbeat information.   The information transmission system according to claim 5, wherein the transmission electrode has an area where a capacitance capable of detecting the heartbeat information is obtained.

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