JP2023051089A - Electric field human body communication system, transmitter and receiver - Google Patents

Abstract

To reduce noise by reducing an electrification voltage or using few frequency of an electrification voltage frequency.SOLUTION: An electric field human body communication system includes: a reference voltage point 204 which a discharge electrode 203 is connected to and a voltage defined to be a reference voltage is obtained from; a discharge path conductive/non-conductive circuit 205 which makes a discharge path between the discharge electrode 203 and the reference voltage point 204 conductive or non-conductive; electrification voltage detection means 206 which detects the electrification voltage of a human body, charged with static electricity, through a transmission electrode 201; and discharge control means 207 which detects whether the voltage detected by the electrification voltage detection means 206 exceeds a predetermined threshold, and when exceeding the predetermined threshold, makes conductive the discharge path of the discharge path conductive/non-conductive circuit 205 to forcibly discharge.SELECTED DRAWING: Figure 2

Description

The present invention relates to an electric field type human body communication system, a transmitting device and a receiving device.

Human body communication is a communication technology that treats the human body as a communication medium. There are two transmission methods for this human body communication. One is the "current communication system" and the other is the "electric field communication system".

The "current communication system" is generally considered to have restrictions on its use. That is, the electrodes of the transmitter and the receiver must be brought into direct contact with the human body, which causes discomfort to the user. In addition, there is a drawback that the contact state between the skin and the electrode changes due to sweating, etc., and the communication becomes unstable.

On the other hand, the electric field method uses an "electric field" that can be thought of as a very weak electric film like static electricity that exists around the human body, and uses changes in the electric field generated on the surface of the human body to transmit information. It is to communicate. The problem with this electric field method is that it cannot match the reference potential because it does not use a physical communication line. The present invention is a communication system, transmitter and receiver using the latter electric field communication. Therefore, noise removal is a problem because it receives a lot of noise from the outside world.

Patent Literature 1 discloses a communication device and a communication system excellent in the electric field coupling method in which electric field coupling between electrodes is made highly efficient and the size of the device is reduced. The communication device of Patent Document 1 includes a first resonant circuit connected in series to an electrode unit configured by two conductive plates, and an electrode unit and the first resonant circuit connected in series. a second resonant circuit connected in parallel to the second resonant circuit; The constant of the resonance circuit is determined such that the voltage applied to the electrode section is higher than the voltage applied to the electrode section and the first resonance circuit connected in series. As a result, an electric field coupling electrode having a very high coupling strength at a target frequency is obtained. That is, it is a proposal to take measures against noise by using excellent electric field coupling electrodes for improving the efficiency of electric field coupling between electrodes. No mention is made of noise removal by software.

Patent Document 2 discloses a human body communication system that achieves both high communication sensitivity and low power consumption. In this human body communication system, a first communication terminal and a second communication terminal communicate via the human body or the like. Each of the first communication terminal and the second communication terminal is provided with an electrode that comes close to or contacts a human body or the like. This electrode is configured by sandwiching an insulating material between a pair of electrode materials. Electrode materials are formed by containing fibrous carbon such as carbon nanotubes, carbon nanofibers, and carbon fiber reinforced plastics in a base material such as metal or resin.
They proposed noise countermeasures using electrodes and electrode materials that achieve both high communication sensitivity and low power consumption, but no mention is made of noise removal by software.

Patent Literature 3 discloses an information transfer system capable of reducing the user's burden when transferring information necessary for route guidance.
This system is an information transfer system for transferring information necessary for route guidance from a mobile terminal holding information to an in-vehicle information terminal. is realized through electric field communication through the user's body when a part of the body of the user who carries the is touched.
As for signal processing, an electric field induced and transmitted by the human body is detected by the transmission/reception electrodes through an insulating film in the human body communication section, and the electric field is converted into an electric signal in the electric field detection optical section. This electrical signal is subjected to signal processing such as amplification and noise removal in a signal processing circuit. Further, the waveform is shaped by the waveform shaping circuit and output to the getting-off point notifying section, the information translating section, etc. through the input/output circuit. However, no particular noise processing based on the charged voltage of the human body charged with static electricity is performed.

In the human body communication described in Patent Document 4, there is a high level of environmental noise induced from nearby power lines and electronic devices, and in order to discriminate significant electric field carriers, a high level of environmental noise removal characteristics are required. , provide a simple receiving circuit by selecting the electrode configuration and connection method. That is, a configuration is adopted in which three conductive layers are provided as receiving electrodes, and the electrodes of the second layer are connected to the electrical reference potential point of the receiving circuit. The distance between the first conductive layer and the second conductive layer on the side that contacts the human body is made wider than the distance between the second-layer electrode and the third conductive layer. Also, the resonance signal is amplified by connecting the capacitance formed by the first conductive layer and the third conductive layer and the resonance inductance corresponding to the carrier frequency.

The communication system of Patent Document 5 includes a first communication device carried by a user, and a second communication device that performs data communication with the first communication device via the user's body. The first communication device includes a first human body communication unit that performs data communication with the second communication device via the human body, and charge control means that controls the amount of charge on the surface of the human body. and the second communication device includes a capacitive touch panel, a human body communication antenna arranged to be close to the human body, and a first proximity portion between the first communication device and the human body. and the electrostatic field in the second proximity portion between the human body and the human body communication antenna to perform data communication with the first communication device via the human body. on the condition that the user has started a touch operation on the touch panel, and if the measured value of the signal strength of the signal received by the second human body communication section is smaller than a predetermined threshold, the signal strength human body communication control means for executing signal strength increase control for increasing the The signal strength increase control increases the voltage for charge amount control in the charge control means of the first communication device in accordance with the difference between the predetermined threshold value and the measured value. The signal strength of the received signal in the human body communication part is increased.

WO2014/087748 WO2015/129048 JP 2010-28394 A JP 2014-135633 A JP 2015-103901 A

In the present invention, in the electric field type human body communication, on the transmission side, noise reduction is aimed at by reducing the charging voltage or using a frequency with a low charging voltage. Further, in the present invention, in the electric field type human body communication, the receiving side can accurately extract the true signal from the received signal containing the noise superimposed on the transmission path by the human body.

An electric field type human body communication system according to an embodiment of the present invention is connected to a transmission electrode for electric field type human body communication that capacitively couples with a human body, and transmits a transmission signal to the transmission electrode using any one of a plurality of frequencies. An electric field type human body communication system comprising: a transmitting device having a signal transmitting unit for transmitting; and a receiving device connected to a receiving electrode for electric field type human body communication that capacitively couples with a human body. a reference voltage point to which an electrode is connected to obtain a reference voltage; and a discharge path conducting/non-conducting circuit for conducting/non-conducting a discharge path between the discharge electrode and the reference voltage point. a charged voltage detecting means for detecting a charged voltage of a human body charged with static electricity via the transmitting electrode; and a voltage detected by the charged voltage detecting means for detecting whether the voltage exceeds a predetermined threshold, and discharge control means for forcibly discharging the discharge path of the discharge path conducting/non-conducting circuit.

A transmission device according to an embodiment of the present invention is connected to a transmission electrode for electric field type human body communication that capacitively couples with a human body, and transmits a transmission signal to the transmission electrode using any one of a plurality of frequencies. The transmitting device of the electric field type human body communication system comprising: a transmitting device having a transmitting unit; and a receiving device connected to a receiving electrode for electric field type human body communication that capacitively couples with the human body, wherein the discharging electrode is connected, a reference voltage point from which a reference voltage is obtained; a discharge path conduction/non-conduction circuit for making a discharge path between the discharge electrode and the reference voltage point conductive/non-conductive; and the transmission electrode. a charged voltage detection means for detecting a charged voltage of a human body charged with static electricity through the charged voltage detection means; and discharge control means for forcibly discharging by making the discharge path of the discharge path conducting/non-conducting circuit conductive.

A receiving device according to an embodiment of the present invention is connected to a transmitting electrode for electric field type human body communication that capacitively couples with a human body, and transmits a transmission signal to the transmitting electrode using any one of a plurality of frequencies. The receiving device of the electric field type human body communication system comprising: a transmitting device having a transmitting unit; and a receiving device connected to a receiving electrode for electric field type human body communication that capacitively couples with the human body, wherein the discharging electrode is connected, a reference voltage point from which a reference voltage can be obtained; a discharge path conduction/non-conduction circuit for making a discharge path between the discharge electrode and the reference voltage point conductive/non-conductive; and the receiving electrode. a charged voltage detection means for detecting a charged voltage of a human body charged with static electricity through the charged voltage detection means; and discharge control means for forcibly discharging by making the discharge path of the discharge path conducting/non-conducting circuit conductive.

1 is a configuration diagram of an embodiment of an electric field type human body communication system according to the present invention; FIG. 1 is a configuration diagram of a transmission device according to each embodiment of the present invention; FIG. FIG. 2 is a diagram for explaining an outline of a transmission device according to each embodiment of the present invention and FFT conversion used by the transmission device; FIG. 4 is a waveform chart showing the process of creating a transmission signal from data by the transmission device according to each embodiment of the present invention; 1 is a configuration diagram of a receiver according to a first embodiment of the present invention; FIG. The block diagram of the transmission apparatus which concerns on the 2nd Embodiment of this invention. The block diagram which shows the modification of the transmission apparatus which concerns on the 2nd Embodiment of this invention. The block diagram of the receiving apparatus which concerns on the 2nd Embodiment of this invention. The block diagram which shows the modification of the receiving apparatus which concerns on the 2nd Embodiment of this invention. The block diagram of the receiver which concerns on the 3rd Embodiment of this invention. 4 is a flowchart showing an example of processing performed by the receiving unit of the receiving device according to the embodiment of the present invention; The block diagram of the receiving apparatus which concerns on the 4th Embodiment of this invention. The figure which shows an example of the clock used by the 1st sampling circuit and 2nd sampling circuit which the receiver based on the 4th Embodiment of this invention has. FIG. 11 is a waveform diagram for explaining the operation of the main part of the receiver according to the fourth embodiment of the present invention; The block diagram of the receiving apparatus which concerns on the 5th Embodiment of this invention. FIG. 11 is a waveform chart for explaining the operation of the first frequency receiving circuit and the second frequency receiving circuit included in the receiver according to the fifth embodiment of the present invention; FIG. 11 is a waveform diagram for explaining the operation of the main part of the receiver according to the fifth embodiment of the present invention; FIG. 11 is a diagram showing an example of waveforms during operation when data is acquired using four receiving electrodes and their received signals by a technique adopted by the receiver of the fifth embodiment of the present invention; FIG. 5 is a diagram showing waveforms of signals received from the receiving electrodes before passing through a low-pass filter in the receiving device of each embodiment of the present invention; FIG. 5 is a diagram showing the waveform of the signal received from the receiving electrode after passing through a low-pass filter in the receiving device of each embodiment of the present invention;

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an electric field type human body communication system, a transmitting device and a receiving device according to the present invention will be described below with reference to the accompanying drawings. In each figure, the same components are denoted by the same reference numerals, and overlapping descriptions are omitted.

FIG. 1 shows a configuration diagram of an embodiment of an electric field type human body communication system according to the present invention. This system is an electric field type human body communication system using the electrostatic electric field on the surface of the person 100 . This system includes a transmitter 200 and a receiver 300 . The transmitter 200 is connected to a transmitter electrode 201 for electric field type human body communication that capacitively couples with the person 100 . The receiving device 300 is connected to a receiving electrode 301 for electric field type human body communication that capacitively couples with the person 100 .

The transmitter 200 has a signal transmitter 202 that transmits a transmission signal to the transmission electrode 201 using one of a plurality of frequencies. The receiver 300 has a receiver 302 that restores the received signal received via the receiver electrode 301 .

A transmitter 200 according to the first embodiment is configured as shown in FIG. That is, the transmitting device 200 is connected to a discharge electrode 203 and has a reference voltage point 204 , a discharge path conduction/non-conduction circuit 205 , charging voltage detection means 206 and discharge control means 207 . A reference voltage point 204 is, for example, a conductive terminal from which a reference voltage is obtained. The reference voltage point 204 is a point connected to the ground side line of the commercial AC power supply to supply a ground potential, a point connected to the negative electrode side of the battery to supply a predetermined voltage if the transmitter 200 is battery-driven, or , a point connected to the conductor chassis of the transmitter 200 to electrically supply a predetermined voltage, and the like.

The discharge path conduction/non-conduction circuit 205 is a circuit such as a switching element that makes the discharge path between the discharge electrode 203 and the reference voltage point 204 conduction/non-conduction. The charged voltage detection means 206 detects the charged voltage of the person 100 charged with static electricity via the transmission electrode 201 . The transmitting electrode 201 and the receiving electrode 301 are insulated on the surface for electrostatic coupling with the person 100, whereas the discharge electrode 203 is an electrode to be touched by the person 100 to discharge, and is composed of a conductor. can do.

The discharge control means 207 detects whether or not the voltage detected by the charged voltage detection means 206 exceeds a predetermined threshold value, and if it exceeds the predetermined threshold value, the discharge path of the discharge path conduction/non-conduction circuit 205 is switched. is turned on for forced discharge. With the above configuration, when the person 100 is charged with a charging voltage exceeding a predetermined threshold, the transmission path will be in an unstable electric field state due to the electric charge of the charging, so the forced discharge stabilizes the electric field. state, and communication can be performed in a state in which noise is reduced.

A receiver 300 according to the first embodiment can be configured as shown in FIG. That is, the receiver 300 is connected to a discharge electrode 303 and has a reference voltage point 304 , a discharge path conduction/non-conduction circuit 305 , charging voltage detection means 306 and discharge control means 307 . A reference voltage point 304 is, for example, a conductive terminal from which a reference voltage is obtained. The reference voltage point 304 is a point connected to the ground side line of the commercial AC power supply to supply a ground potential, a point connected to the negative electrode side of the battery to supply a predetermined voltage if the receiving device 300 is battery-driven, or , a point connected to the conductor chassis of the receiving device 300 to electrically supply a predetermined voltage, and the like.

The discharge path conduction/non-conduction circuit 305 is a circuit such as a switching element that makes the discharge path between the discharge electrode 303 and the reference voltage point 304 conduction/non-conduction. The charged voltage detection means 306 detects the charged voltage of the person 100 charged with static electricity via the receiving electrode 301 . The transmitting electrode 201 and the receiving electrode 301 are insulated on the surface for electrostatic coupling with the person 100, whereas the discharge electrode 303 is an electrode for the person 100 to touch and discharge, and is composed of a conductor. can do.

The discharge control means 307 detects whether or not the voltage detected by the charging voltage detection means 306 exceeds a predetermined threshold value, and if it exceeds the predetermined threshold value, the discharge path of the discharge path conduction/non-conduction circuit 305 is switched. is turned on for forced discharge. With the above configuration, when the person 100 is charged with a charging voltage exceeding a predetermined threshold value, the reception path will be in an unstable electric field state due to the charge of the charging, so the forced discharge stabilizes the electric field state. state, and communication can be performed in a state in which noise is reduced.

In this embodiment, the transmitter is provided with charging voltage frequency detection means 208 and transmission frequency control means 209, as shown in FIG. The charged voltage frequency detection means 208 detects the frequency of the charged voltage of the person 100 via the discharge electrode 203 or the transmission electrode 201 . The transmission frequency control means 209 operates the charging voltage frequency detection means 208 after the discharge control means 207 operates to detect the frequency of the charging voltage of the person 100, controls the signal transmission section 202, and controls the charging voltage frequency detection means 208. A transmission signal is transmitted at one frequency other than the frequency detected by the voltage frequency detection means 208 . The charging voltage frequency detection means 208 can perform frequency analysis by FFT (Fast Fourier Transform) to obtain the frequency of the included signal.

FIG. 2A shows the FFT transform. The signal (FIG. 2A(a)) arriving at the charging voltage frequency detection means 208 can be subjected to Fourier series expansion as shown in FIG. 2A(b) to obtain the frequency spectrum shown in FIG. 2A(c). In this embodiment, the signal (FIG. 2A(a)) arriving at the charging voltage frequency detection means 208 is digitized and accumulated, and the accumulated data is subjected to FFT conversion to obtain a frequency spectrum.

When transmitting data composed of 01 as shown in FIG. 2B(b), the signal transmission unit 202 modulates the carrier wave with the modulated signal shown in FIG. 2B(a) and modulates the modulated signal shown in FIG. Send as a signal. That is, the carrier wave is a signal in which the pulses shown in FIG. 2B(c) are continuous. Therefore, the data (FIG. 2B (b)) is modulated as a signal in which H and L continue for one cycle (1H) when 1, and as a signal which continues all L in one cycle (1H) when 0. A signal (FIG. 2B(a)) is created, and a modulated signal (FIG. 2B(c)) is obtained and transmitted by modulating a carrier wave with a modulating signal (FIG. 2B(a)).

The signal transmission unit 202 can transmit at a plurality of frequencies such as 33 MHz, 100 MHz, 123 MHz, and so on. It is possible to avoid deterioration of the communication state such as mixing of the transmission signal with noise.

FIG. 4 shows a configuration diagram of a transmission device 200 according to the second embodiment. The transmitting device according to this embodiment is provided with a test receiving electrode 211 and a charging voltage frequency detection auxiliary means 212 in addition to the configuration of the first embodiment shown in FIG. In the charging voltage frequency detection auxiliary means 212 , the input terminal 213 is the position where the signal from the test receiving electrode 211 is input.

The charge voltage frequency detection auxiliary means 212 causes the signal transmission section 202 to transmit a transmission signal of a predetermined frequency, receives the signal from the input terminal 213, and detects the frequency component of the input signal from the signal transmission section 202. The frequency component of the transmitted transmission signal is removed and supplied to the charge voltage frequency detection auxiliary means 212 to detect the frequency of the charge voltage of the human body. The charging voltage frequency detection auxiliary means 212 receives the transmission signal of the predetermined frequency transmitted from the signal transmission section 202, and detects the frequency component of the transmission signal transmitted from the signal transmission section 202 from the frequency component of the input signal. can be removed.

The transmission frequency control means 209 causes the transmission signal to be transmitted at one frequency other than the frequency detected by the charging voltage frequency detection means 208 under the control of the charging voltage frequency detection auxiliary means 212 .

FIG. 5 shows a modification of the transmission device 200 according to the second embodiment. This embodiment has a capacitor C connected between the signal line extending from the signal transmission section 202 to the transmission electrode 201 and the input terminal 213 . A combined signal obtained by combining the signal from the test receiving electrode 211 and the signal transmitted from the signal transmitting section 202 and passed through the capacitor C is input to the input terminal 213 . This embodiment deals with the fact that when the person 100 is not present, the test receiving electrode 211 cannot receive a signal obtained by synthesizing the signal transmitted from the signal transmitting section 202 and the signal related to the charging voltage.

In this embodiment, the charge voltage frequency detection auxiliary means 212 receives the composite signal from the input terminal 213 and removes the frequency component of the transmission signal transmitted from the signal transmission section 202 from the frequency component of the composite signal. is given to the charging voltage frequency detecting means 208 to detect the frequency of the charging voltage of the person 100. FIG.

According to the above configuration, the charged voltage frequency detection auxiliary means 212 acquires the transmission signal transmitted from the signal transmission section 202 or information such as the frequency and amplitude of the transmission signal, so that the embodiment of FIG. , the signal obtained by synthesizing the transmission signal actually transmitted from the signal transmission section 202 and the signal of the charging voltage is not actually obtained from the test receiving electrode 211, but the synthesized signal is taken in from the input terminal 213. can be done. The processing after obtaining the combined signal can be performed in the same manner as in the embodiment of FIG.

FIG. 6 shows a configuration diagram of a receiving device 300 according to the second embodiment. Unlike the embodiment of the receiving device 300 shown in FIG. 3, the receiving device 300 according to the second embodiment includes a test transmitting electrode 311 capacitively coupled with the human body, a test signal transmitting section 309, a charged voltage frequency A detection means 312 and a storage means 308 are additionally provided. In the charging voltage frequency detection means 312 , an input terminal 313 is provided at a position for inputting a signal from the receiving electrode 301 .

In the above, the test signal transmission section 309 transmits a test transmission signal to the test transmission electrode 311 using a predetermined frequency. The charging voltage frequency detection means 312 causes the test signal transmitting section 309 to transmit a transmission signal of a predetermined frequency, and inputs a signal synthesized with the charging voltage frequency signal by communication via the person 100 from the input terminal 313. Then, the frequency component of the test transmission signal transmitted from the test signal transmission section 309 is removed from the frequency component of this input signal to detect the charged voltage frequency signal of the human body. The storage means 308 stores (digitized) the detected charging voltage frequency signal. When restoring the transmission signal transmitted from the signal transmission section 202 of the transmission device 200, the reception section 302 converts the charged voltage frequency detection signal (digital data into an analog signal) stored in the storage means 308. is used to remove unnecessary frequency components from the frequency components of the signal from the receiving electrode 301 . Specifically, the reception unit 302 removes unnecessary frequency components using a filter or the like. The test signal transmitting section 309 and the charging voltage frequency detecting means 312 of the present embodiment are operated before normal signal reception to store the charging voltage frequency signal in the storage means 308, and the operation is suspended during normal signal reception. state.

FIG. 7 shows a configuration diagram according to a modification of the receiving device 300 according to the second embodiment. In this embodiment, a signal line extending from the test signal transmission section 309 to the test transmission electrode 311 and a capacitor C connected between the reception electrode 301 and the input terminal 313 are provided. and the signal transmitted from the signal transmission section 202 and passed through the capacitor C are combined to input to the input terminal 313 . This embodiment deals with the fact that when the person 100 is not present, the reception electrode 301 cannot receive a signal obtained by synthesizing the signal transmitted from the test signal transmission section 309 and the signal related to the charging voltage.

In this embodiment, the signal from the receiving electrode 301 and the signal transmitted from the test signal transmitting section 309 and passed through the capacitor C are combined to form a combined signal, which is input to the input terminal 313. Therefore, the charging voltage frequency detection means 312 receives a signal from the input terminal 313 and removes the frequency component of the test transmission signal transmitted from the test signal transmission section 309 from the frequency component of this input signal. to detect the charged voltage frequency signal of the human body.
The charged voltage frequency signal of the human body is stored in the storage means 308 and processed in the same manner as the receiver 300 according to the second embodiment in FIG.

FIG. 8 shows a block diagram of a receiver 300 according to the third embodiment. The receiving device 300 of this embodiment is connected to a plurality of (here, four) receiving electrodes 301-1 to 301-4, and FFT means 314-1 to 314, which are fast Fourier transform means for performing fast Fourier transform. -4.

Noise is removed using the technique of the embodiment already described, and the reception unit 302 receives signals from all of the reception electrodes 301-1 to 301-4 and accumulates them in time series (digitized). The accumulated signals of the receiving electrodes 301-1 to 301-4 are applied to the FFT means 314-1 to 314-4 to perform fast Fourier transform, and based on the result of the fast Fourier transform, the signal transmitting section 202 of the transmitting device 200 recover the transmitted signal sent from

FIG. 9 shows an example of processing performed by the receiving unit 302 of the receiving device 300 according to this embodiment. In the present embodiment, the case of receiving "authentication" data is taken as an example. First, signal reception processing is performed simultaneously by all the receiving electrodes, noise is removed by a filter or the like, and normal received analog signals are obtained (S11). Next, the signals for each electrode are digitized and stored in chronological order for each electrode (S12). The time-series data for each electrode is FFT-transformed (S13). Furthermore, the FFT conversion results for each electrode are integrated, and the maximum frequency is specified as the frequency of the transmission signal (S14).

Next, the accumulated time-series data for each electrode is FFT-transformed at predetermined time intervals (S15). Furthermore, the FFT conversion result for each electrode is integrated in units of time, the frequency of the transmission signal and the magnitude of the specified frequency component are compared with a threshold, and converted to 0 or 1 in units of time (S16). A data string of 0s and 1s is converted into characters in predetermined bit units and stored (S17). It is detected whether the stored character string matches the authentication data (S18). Here, when it matches with the authentication data, it is determined that the authentication is completed and the process proceeds to the next step (S19). On the other hand, if NO in step S18, the process returns to step S11 to continue the process.

FIG. 10 shows a configuration diagram of a receiver 300 according to the fourth embodiment. In the receiving device 300 according to the fourth embodiment, two electrodes, a first receiving electrode 301-1 and a second receiving electrode 301-2, are connected, and a first sampling circuit 315 and a second sampling circuit are connected. A circuit 316, a signal transforming means 317, a binarization circuit 318, and a data extracting means 319 are provided. The first sampling circuit 315 receives a signal from the first electrode 301-1 at a first timing for a predetermined period. The second sampling circuit 316 receives the predetermined period signal from the second electrode 301-2 at a second timing different from the first timing.

Further, the signal transforming means 317 obtains a sum signal or product signal of the signal received by the first sampling circuit 315 and the signal received by the second sampling circuit 316 . A binarization circuit 318 binarizes the sum signal or the product signal into H level and L level using a predetermined wave height threshold. Further, the data extracting means 319 extracts the data of 1 and 0 based on the length of the period in which the binarized H level is substantially continuous and the length of the binarized L level.

A specific example is shown in FIG. The first sampling circuit 315 receives a signal from the first electrode 301-1 for a predetermined period at the first timing, which is the rise of the clock indicated by (a). The second sampling circuit 316 receives a signal from the second electrode 301-2 for a predetermined period at the second timing, which is the rise of the clock indicated by (b).

When the signal received by the first sampling circuit 315 is as shown in FIG. 12(c) and the signal received by the second sampling circuit 316 is as shown in FIG. 12(d), the signal transforming means 317 When summing the signals, a sum signal as shown in FIG. 12(e) is obtained. When this is binarized by the binarization circuit 318 using the wave height threshold TH, a signal having H level and L level signals is obtained as shown in FIG. 12(f). The data retrieving means 319 converts this into 0 and 1 in a predetermined time width, and can acquire data such as 10101110000 . . . as shown below the waveform in FIG. 12(f).

FIG. 13 shows a configuration diagram of a receiver 300 according to the fifth embodiment. In the receiving device 300 according to the fifth embodiment, two electrodes, a first receiving electrode 301-1 and a second receiving electrode 301-2, are connected, and a first frequency receiving circuit 321 and a second receiving electrode 301-2 are connected. A frequency receiving circuit 322, a signal transforming means 317, a binarizing circuit 318, and a data extracting means 319 are provided. The first frequency receiving circuit 321 receives a signal from the first electrode 301-1 by performing sampling at a first frequency every predetermined time. The second frequency receiving circuit 322 receives a signal from the second electrode 301-2 by performing sampling at a second frequency every predetermined time.

That is, the first frequency receiving circuit 321 performs sampling at the first frequency (shown in (h) of FIG. 14) for one reception period as shown in (g) of FIG. 14 to receive the signal. . The second frequency receiving circuit 322 receives signals by sampling at a second frequency (shown in (i) of FIG. 14). In other words, the first frequency receiving circuit 321 performs sampling with the pulse width of the pulse shown in FIG. 14(h), and the second frequency receiving circuit 322 samples the pulse shown in FIG. 14(i). Sampling with pulse width. In this example, the frequency of first frequency receiving circuit 321 is twice the frequency of second frequency receiving circuit 322 .

When the signal received by the first frequency receiving circuit 321 is as shown in FIG. 15(j) and the signal received by the second frequency receiving circuit 322 is as shown in FIG. When 317 sums the signals, a sum signal as shown in FIG. 15(l) is obtained. When this is binarized by the binarization circuit 318 using the wave height threshold TH, a signal having H level and L level signals is obtained as shown in FIG. 15(m). The data retrieving means 319 converts this into 0 and 1 in a predetermined time width, and can acquire data such as 10101110000 . . . as shown below the waveform in FIG. 15(m).

Even in the case of binarization as shown in FIGS. 12 and 15, the following method can be employed to determine whether or not the signal component is correct. In the communication system of this embodiment having the transmitting device 200 and the receiving device 300, the pulse width for 1 bit of the correct signal (time t _bit shown in FIG. 15) is known in the receiving device 300 . The time t _H of the signal component that is "H" with respect to this pulse width (time t _bit ) is used as a criterion for judgment. That is, when the time t _H has a length of 80% or more of the time t _bit , it is determined as a correct signal component. Here, the reason for setting it to 80% will be explained. The reason is that at 50%, erroneous detection becomes 1/2, and a correct signal component cannot be determined with high accuracy. Also, in about 70% of cases, the signal error detection rate increases when the beginning of the signal is missing due to noise or when the signal is superimposed due to noise in the time zone where there is no signal. end up On the other hand, by setting it to 80% or more, the factors of false detection for each of the presence of a signal and the absence of a signal are reduced. However, the presence or absence of a signal must be determined).

FIG. 16 shows an example of waveforms during operation when data is acquired using four receiving electrodes and their received signals by the technique adopted by the receiver 300 of the fifth embodiment. FIG. 16(a) shows a binarized original signal, and FIG. 16(b) shows data converted into 0s and 1s. 16(c), (d), (e), and (f) are clocks corresponding to the frequencies used for each of the four receiving electrodes. FIG. 16(g) is the sum signal of the four signals.

As is clear from the sum signal of the four signals (Fig. 16(g)), the H part in the part that should be data 1 is exaggerated, and it is understood that accurate data acquisition will be possible. Although there is a range in which H and L are alternately repeated even in the portion that should be data 1, the total width (time) of H and L in the range in which H and L are alternately repeated is L. H or L may be determined by a majority decision based on the comparison of the total width (time).

In the receiving device 300 according to the fourth embodiment, the receiving device 300 according to the fifth embodiment, and other receiving devices 300, a low-pass filter is applied to the signal received from the receiving electrode. It can be seen that signal processing using .alpha. will provide accurate data acquisition. 17 shows the signal received from the receiving electrode (before using the low-pass filter), and FIG. 18 shows the signal received from the receiving electrode (after using the low-pass filter). Considering that binarization is performed using the crest threshold TH when binarizing these signals, it is obvious that using a low-pass filter is preferable.

In both the receiving device 300 according to the fourth embodiment and the receiving device 300 according to the fifth embodiment, two receiving electrodes are shown. Even if the processing method for the signal received by each receiving electrode is the processing method of the receiving device 300 according to the fourth embodiment, the processing of the receiving device 300 according to the fifth embodiment It may be a method.

100 people 200 transmitter 201 transmitter electrode 202 signal transmitter 203 discharge electrode 204 reference voltage point 205 discharge path conduction/non-conduction circuit 206 charge voltage detection means 207 discharge control means 208 charge voltage frequency detection means 209 transmission frequency control means 211 test Receiving electrode 212 Auxiliary means for detecting charged voltage frequency 213 Input terminal 300 Receiving device 301, 301-1 to 301-4 Receiving electrode 302 Receiving section 303 Discharge electrode 304 Reference voltage point 305 Discharge path conduction/non-conduction circuit 306 Charged voltage detection Means 307 Discharge control means 308 Storage means 309 Test signal transmitter 311 Test transmission electrode 312 Charged voltage frequency detection means 313 Input terminals 314-1 to 314-4 FFT means 315 First sampling circuit 316 Second sampling circuit 317 Signal transforming means 318 Binary circuit 319 Data extracting means 321 First frequency receiving circuit 322 Second frequency receiving circuit

Claims (20)

a transmission device connected to a transmission electrode for electric field type human body communication that capacitively couples with a human body, and having a signal transmission unit that transmits a transmission signal to the transmission electrode using any one of a plurality of frequencies; An electric field type human body communication system comprising a receiving device connected to a receiving electrode for capacitively coupled electric field type human body communication,
The transmitting device includes:
Discharge electrodes are connected,
a reference voltage point at which a reference voltage is obtained;
a discharge path conduction/non-conduction circuit for conducting/non-conducting a discharge path between the discharge electrode and the reference voltage point;
a charged voltage detection means for detecting a charged voltage of a human body charged with static electricity via the transmission electrode;
It is detected whether the voltage detected by the charged voltage detection means exceeds a predetermined threshold, and if the predetermined threshold is exceeded, the discharge path of the discharge path conducting/non-conducting circuit is made conductive to forcibly discharge. An electric field type human body communication system, comprising: a control means; The transmitting device includes:
charged voltage frequency detection means for detecting the frequency of the charged voltage of the human body via the discharge electrode or the transmission electrode;
After the discharge control means operates, the charged voltage frequency detection means is operated to detect the frequency of the charged voltage of the human body, and the signal transmission section is controlled to remove the frequency detected by the charged voltage frequency detection means. 2. The electric field type human body communication system according to claim 1, further comprising transmission frequency control means for transmitting a transmission signal at one frequency. The transmitting device includes:
a test receiving electrode capacitively coupled with the human body;
an input terminal for inputting a signal from the test receiving electrode;
A transmission signal having a predetermined frequency is transmitted from the signal transmission unit, the signal is input from the input terminal, and the frequency component of the transmission signal transmitted from the signal transmission unit is removed from the frequency component of the input signal to obtain the charging voltage. A charged voltage frequency detection auxiliary means for detecting the frequency of the charged voltage of the human body by applying it to the frequency detection means,
3. The transmission frequency control means according to claim 2, wherein the transmission frequency control means causes the transmission signal to be transmitted at one frequency other than the frequency detected by the charging voltage frequency detection means under the control of the charging voltage frequency detection auxiliary means. Electromagnetic human body communication system. a capacitor connected between a signal line extending from the signal transmission unit to the transmission electrode and the input terminal;
A combined signal obtained by combining the signal from the test receiving electrode and the signal transmitted from the signal transmitting unit is input to the input terminal,
The charging voltage frequency detection auxiliary means inputs the composite signal from the input terminal, removes the frequency component of the transmission signal transmitted from the signal transmitting section from the frequency component of the composite signal, and detects the charging voltage frequency detection means. 4. The electric field type human body communication system according to claim 3, wherein the electric field type human body communication system according to claim 3, characterized in that the frequency of the charged voltage of a person is detected. The receiving device includes:
a transmission electrode for testing capacitively coupled with a human body;
a test signal transmitter for transmitting a test transmission signal to the test transmission electrode using a predetermined frequency; an input terminal for inputting a signal from the reception electrode;
A transmission signal having a predetermined frequency is transmitted from the test signal transmission section, the signal is input from the input terminal, and the frequency component of the test transmission signal transmitted from the test signal transmission section is derived from the frequency component of the input signal. a charged voltage frequency detection means for removing and detecting the frequency of the charged voltage of the human body;
storage means for storing the charging voltage frequency signal detected by the charging voltage frequency detection means;
removing unnecessary frequency components from the frequency components of the signal from the receiving electrode using the stored charging voltage frequency signal when restoring the transmission signal transmitted from the signal transmission unit of the transmission device; The electric field type human body communication system according to claim 1. a capacitor connected between a signal line extending from the test signal transmission unit to the test transmission electrode and the input terminal;
A combined signal obtained by combining the signal from the receiving electrode and the signal transmitted from the test signal transmitting unit is input to the input terminal,
The charged voltage frequency detection means inputs the combined signal from the input terminal, removes the frequency component of the transmission signal transmitted from the test signal transmission section from the frequency component of the combined signal, and generates the charged voltage frequency signal. 6. The electric field type human body communication system according to claim 5, wherein: The receiving device includes:
Discharge electrodes are connected,
a reference voltage point at which a reference voltage is obtained;
a discharge path conduction/non-conduction circuit for conducting/non-conducting a discharge path between the discharge electrode and the reference voltage point;
a charged voltage detection means for detecting a charged voltage of a human body charged with static electricity via the receiving electrode;
It is detected whether the voltage detected by the charged voltage detection means exceeds a predetermined threshold, and if the predetermined threshold is exceeded, the discharge path of the discharge path conducting/non-conducting circuit is made conductive to forcibly discharge. 5. The electric field type human body communication system according to any one of claims 1 to 4, further comprising a control means. The receiving device includes:
Multiple receiving electrodes are connected,
a Fast Fourier Transform means for performing a Fast Fourier Transform;
and
Signals are received from all of the receiving electrodes and accumulated in time series, the signals accumulated for each of the receiving electrodes are applied to the Fourier transform means and fast Fourier transformed, and based on the result of the fast Fourier transform, the transmitter of the transmitting device 5. The electric field type human body communication system according to any one of claims 1 to 4, wherein the transmission signal transmitted from the signal transmission unit is restored. The receiving device includes:
Multiple receiving electrodes are connected,
sampling circuits of the same number as the plurality of receiving electrodes for receiving signals from the plurality of receiving electrodes at different timings for a predetermined period;
signal transforming means for obtaining a sum signal or a product signal of all the signals received by the plurality of sampling circuits;
a binarization circuit that binarizes the sum signal or the product signal into H level and L level using a predetermined wave height threshold;
data extracting means for extracting data of 1 and 0 based on the length of a period in which the binarized H level is substantially continuous and the length of the binarized L level in succession; Item 5. The electric field type human body communication system according to any one of Items 1 to 4. The receiving device includes:
Multiple receiving electrodes are connected,
frequency receiving circuits of the same number as the plurality of receiving electrodes, each sampling at a different frequency from each of the plurality of receiving electrodes at predetermined time intervals to receive signals;
signal transforming means for obtaining a sum signal or a product signal of all the signals received by the plurality of frequency receiving circuits;
a binarization circuit that binarizes the sum signal or the product signal into H level and L level using a predetermined wave height threshold;
data extracting means for extracting data of 1 and 0 based on the length of a period in which the binarized H level is substantially continuous and the length of the binarized L level in succession; Item 5. The electric field type human body communication system according to any one of Items 1 to 4. a transmission device connected to a transmission electrode for electric field type human body communication that capacitively couples with a human body, and having a signal transmission unit that transmits a transmission signal to the transmission electrode using any one of a plurality of frequencies; and a receiving device connected to a receiving electrode for capacitively coupling electric field type human body communication,
Discharge electrodes are connected,
a reference voltage point at which a reference voltage is obtained;
a discharge path conducting/non-conducting circuit for conducting/non-conducting the discharge path between the discharge electrode and the reference voltage point;
a charged voltage detection means for detecting a charged voltage of a human body charged with static electricity via the transmission electrode;
It is detected whether the voltage detected by the charged voltage detection means exceeds a predetermined threshold, and if the predetermined threshold is exceeded, the discharge path of the discharge path conducting/non-conducting circuit is made conductive to forcibly discharge. A transmitter for an electric field type human body communication system, comprising: a control means; charged voltage frequency detection means for detecting the frequency of the charged voltage of the human body via the discharge electrode or the transmission electrode;
After the discharge control means operates, the charged voltage frequency detection means is operated to detect the frequency of the charged voltage of the human body, and the signal transmission section is controlled to remove the frequency detected by the charged voltage frequency detection means. 12. The transmission device of the electric field type human body communication system according to claim 11, further comprising transmission frequency control means for transmitting a transmission signal at one frequency. a test receiving electrode capacitively coupled with the human body;
an input terminal for inputting a signal from the test receiving electrode;
A transmission signal having a predetermined frequency is transmitted from the signal transmission unit, the signal is input from the input terminal, and the frequency component of the transmission signal transmitted from the signal transmission unit is removed from the frequency component of the input signal to obtain the charging voltage. A charged voltage frequency detection auxiliary means for detecting the frequency of the charged voltage of the human body by applying it to the frequency detection means,
13. The transmission frequency control means according to claim 12, wherein the transmission frequency control means causes the transmission signal to be transmitted at one frequency other than the frequency detected by the charging voltage frequency detection means under the control of the charging voltage frequency detection auxiliary means. A transmitting device for an electric field type human body communication system. a capacitor connected between a signal line extending from the signal transmission unit to the transmission electrode and the input terminal;
A combined signal obtained by combining the signal from the test receiving electrode and the signal transmitted from the signal transmitting unit is input to the input terminal,
The charging voltage frequency detection auxiliary means inputs the composite signal from the input terminal, removes the frequency component of the transmission signal transmitted from the signal transmitting section from the frequency component of the composite signal, and detects the charging voltage frequency detection means. 14. The transmitting device of the electric field type human body communication system according to claim 13, wherein the frequency of the charged voltage of the human body is detected by applying it to the human body. a transmission device connected to a transmission electrode for electric field type human body communication that capacitively couples with a human body, and having a signal transmission unit that transmits a transmission signal to the transmission electrode using any one of a plurality of frequencies; The receiving device of the electric field type human body communication system comprising: a receiving device connected to a receiving electrode for capacitively coupled electric field type human body communication,
Discharge electrodes are connected,
a reference voltage point at which a reference voltage is obtained;
a discharge path conduction/non-conduction circuit for conducting/non-conducting a discharge path between the discharge electrode and the reference voltage point;
a charged voltage detection means for detecting a charged voltage of a human body charged with static electricity via the receiving electrode;
It is detected whether the voltage detected by the charged voltage detection means exceeds a predetermined threshold, and if the predetermined threshold is exceeded, the discharge path of the discharge path conducting/non-conducting circuit is made conductive to forcibly discharge. A receiving apparatus for an electric field type human body communication system, comprising control means. a transmission electrode for testing capacitively coupled with a human body;
a test signal transmitter for transmitting a test transmission signal to the test transmission electrode using a predetermined frequency; an input terminal for inputting a signal from the reception electrode;
A transmission signal having a predetermined frequency is transmitted from the test signal transmission section, the signal is input from the input terminal, and the frequency component of the test transmission signal transmitted from the test signal transmission section is derived from the frequency component of the input signal. a charged voltage frequency detection means for removing and detecting the frequency of the charged voltage of the human body;
storage means for storing the charging voltage frequency signal detected by the charging voltage frequency detection means;
removing unnecessary frequency components from the frequency components of the signal from the receiving electrode using the stored charging voltage frequency signal when restoring the transmission signal transmitted from the signal transmission unit of the transmission device; 16. The receiving device of the electric field type human body communication system according to claim 15. a capacitor connected between a signal line extending from the test signal transmission unit to the test transmission electrode and the input terminal;
A combined signal obtained by combining the signal from the receiving electrode and the signal transmitted from the test signal transmitting unit is input to the input terminal,
The charged voltage frequency detection means inputs the combined signal from the input terminal, removes the frequency component of the transmission signal transmitted from the test signal transmission section from the frequency component of the combined signal, and generates the charged voltage frequency signal. 17. The receiving device of the electric field type human body communication system according to claim 16, wherein the receiving device of the electric field type human body communication system is created. Multiple receiving electrodes are connected,
a Fast Fourier Transform means for performing a Fast Fourier Transform;
and
Signals are received from all of the receiving electrodes and accumulated in time series, the signals accumulated for each of the receiving electrodes are applied to the Fourier transform means and fast Fourier transformed, and based on the result of the fast Fourier transform, the transmitter of the transmitting device 18. The receiving apparatus of the electric field type human body communication system according to any one of claims 15 to 17, wherein a transmission signal transmitted from the signal transmitting section is restored. Multiple receiving electrodes are connected,
sampling circuits of the same number as the plurality of receiving electrodes for receiving signals from the plurality of receiving electrodes at different timings for a predetermined period;
signal transforming means for obtaining a sum signal or a product signal of all the signals received by the plurality of sampling circuits;
a binarization circuit that binarizes the sum signal or the product signal into H level and L level using a predetermined wave height threshold;
data extracting means for extracting data of 1 and 0 based on the length of a period in which the binarized H level is substantially continuous and the length of the binarized L level in succession; Item 18. The receiving device for an electric field type human body communication system according to any one of Items 15 to 17. Multiple receiving electrodes are connected,
frequency receiving circuits of the same number as the plurality of receiving electrodes, each sampling at a different frequency from each of the plurality of receiving electrodes at predetermined time intervals to receive signals;
signal transforming means for obtaining a sum signal or a product signal of all the signals received by the plurality of frequency receiving circuits;
a binarization circuit that binarizes the sum signal or the product signal into H level and L level using a predetermined wave height threshold;
data extracting means for extracting data of 1 and 0 based on the length of a period in which the binarized H level is substantially continuous and the length of the binarized L level in succession; Item 18. The receiving device for an electric field type human body communication system according to any one of Items 15 to 17.

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