Measurement system and signal read-out device

Abstract

This measurement system (10) comprises: a plurality of measurement terminals (11) that measure biological signals; and a signal read-out device (12). The measurement terminals each comprise: a biological signal acquisition unit (111); a terminal reception unit (113); and a terminal transmission unit (114). The signal read-out device (12) comprises: a read-out reception unit (121); and a read-out electrode unit (122). At least two measurement terminals that constitute a differential amplifier circuit are electrically connected to one another through a living body, and a biological signal is transmitted from the terminal transmission unit of one measurement terminal and received by the terminal reception unit of the other measurement terminal. When the read-out electrode unit is disposed so as to be in direct contact with the living body, or so as to be electrically connected by capacitive coupling, the read-out reception unit reads out the biological signal from the measurement terminal by using a quasi-electrostatic field.

Description

Measurement system and signal readout device

[0001] The present invention relates to a measurement system and a signal readout device for measuring biological signals.

[0002] Currently, many wearable devices and electronic devices are connected via wireless communication such as Wi-Fi and Bluetooth Low Energy (BLE). These wireless communications have fixed bandwidths, and as the number of connected devices increases, bandwidth congestion can cause communication stability to deteriorate.

[0003] In measuring biosignals, wearable terminals (hereinafter referred to as measurement terminals) are attached to multiple parts of the body, and the voltage information required for measuring biosignals can be amplified using a differential amplifier circuit configuration that propagates modulated signals between each other on the user's body (Non-Patent Document 1).

[0004] Kento Watanabe et al., "Proposal of a Wireless Electrocardiogram Measurement Circuit Using the Human Body as Inter-element Wiring," Proceedings of the 2023 Institute of Electronics, Information and Communication Engineers General Conference, Vol. 1 (2023), p. 467.

[0005] In the above-mentioned biosignal measurement, the amplified signal is converted into a digital signal and transmitted from each device via a wireless module to a smartphone, server, etc. As a result, pairing with BLE or the like is required for each device worn by a user, and the communication bandwidth becomes constrained as the number of devices worn increases, which has been a problem.

[0006] In order to solve the above-mentioned problems, the measurement system of the present invention comprises a plurality of measurement terminals for measuring biosignals and a signal readout device, wherein the measurement terminal comprises a biosignal acquisition unit for acquiring biosignals, a terminal receiving unit, a receiving electrode unit connected to the terminal receiving unit, a terminal transmitting unit, and a transmitting electrode unit connected to the terminal transmitting unit, and the signal readout device comprises a readout receiving unit and a readout electrode unit connected to the readout receiving unit, at least two of the plurality of measurement terminals form a differential amplifier circuit, the two measurement terminals are electrically connected via a living body, the biosignal is transmitted from the terminal transmitting unit of one of the two measurement terminals and received by the terminal receiving unit of the other measurement terminal, and when the readout electrode unit is positioned so as to be in direct contact with the living body or so as to be electrically connected by capacitive coupling, the readout receiving unit reads out the biosignal from the measurement terminal in a quasi-electrostatic field.

[0007] Furthermore, the signal reading device of the present invention is a signal reading device that reads out biosignals from at least two measurement terminals, among a plurality of measurement terminals, which have a terminal transmitting unit that measures the biosignal and transmits the biosignal via a transmitting electrode unit, and which form a differential amplifier circuit via a living body, and is equipped with a readout receiving unit and a readout electrode unit connected to the readout receiving unit, and when the readout electrode unit is positioned so as to be in direct contact with the living body or so as to be electrically connected by capacitive coupling, the readout receiving unit reads out the biosignal from the measurement terminal in a quasi-electrostatic field.

[0008] According to the present invention, it is possible to provide a measurement system and a signal readout device that can reduce the bandwidth required for transmitting and receiving biological signals and prevent bandwidth congestion.

[0009] FIG. 1 is a schematic diagram showing the configuration of a measurement system and a signal readout device according to a first embodiment of the present invention. FIG. 2 is a schematic diagram showing an example of the configuration of a signal readout device according to the first embodiment of the present invention. FIG. 3 is a schematic diagram showing an example of the configuration of a signal readout device according to the first embodiment of the present invention. FIG. 4 is a schematic diagram showing an example of the configuration of a signal readout device according to the first embodiment of the present invention. FIG. 5 is a schematic diagram showing the configuration of a readout receiving unit in a signal readout device according to a second embodiment of the present invention. FIG. 6 is a schematic diagram showing an example of the configuration of a readout receiving unit in a signal readout device according to the second embodiment of the present invention. FIG. 7 is a diagram for explaining an example of a measurement system according to a third embodiment of the present invention. FIG. 8 is a diagram for explaining an example of a measurement system according to the third embodiment of the present invention. FIG. 9 is a diagram for explaining an example of a measurement system according to the third embodiment of the present invention. FIG. 10 is a diagram for explaining an example of a measurement system according to the third embodiment of the present invention.

[0010] First Embodiment A measurement system and a signal readout device according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG.

[0011] <Configuration of measurement system and signal readout device> As shown in Fig. 1, a measurement system 10 according to this embodiment includes a plurality of measurement terminals 11 worn by a user and a signal readout device 12. In the figure, dotted and dashed lines indicate the paths of propagating signals.

[0012] The measurement terminal 11 includes a biosignal acquisition unit 111, a circuit unit 112, a terminal receiving unit 113, and a terminal transmitting unit 114. The measurement terminal 11 also includes a receiving electrode unit 115 connected to the terminal receiving unit 113, and a transmitting electrode unit 116 connected to the terminal transmitting unit 114. At least two of the multiple measurement terminals, namely, measurement terminals 11_1 and 11_2, form a differential amplifier circuit.

[0013] The biological signal acquisition unit 111 comes into direct or indirect contact with the human body (living body) 1 and acquires a biological signal.

[0014] The terminal transmitting unit 114 transmits the signal obtained from the biological signal acquiring unit 111 or the amplified signal to the other measuring terminal 11_2 constituting the differential amplifier circuit via the transmitting electrode unit 116. For example, the terminal transmitting unit 114 modulates the signal and transmits it.

[0015] The terminal receiving section 113 receives a signal from the other measuring terminal 11_2 that configures the differential amplifier circuit via the receiving electrode section 115. For example, the terminal transmitting section 114 demodulates the received signal.

[0016] The circuit section 112 amplifies the signal by differential amplification based on the signal obtained from the biological signal acquisition section 111 and the signal obtained from the terminal receiving section 113 .

[0017] The signal readout device 12 includes a readout receiving unit 121 and a readout electrode unit 122. The signal readout device 12 may also include a storage unit 123.

[0018] The reading and receiving unit 121 receives the biosignal from the transmitting electrode unit 116 of the measuring terminal 11 via the reading electrode unit 122. At this time, the signal reading device 12 receives the biosignal in the form of a modulated signal used for transmitting and receiving the biosignal between the measuring terminals 11.

[0019] In the measurement terminal 11, it is desirable that the biosignal acquisition unit 111 be placed in direct contact with the human body (living body) 1 (for example, the user's skin) to measure the biosignal.

[0020] In the measurement terminal 11, the biosignal acquisition unit 111 may be placed in indirect contact with the skin via clothing 2 or the like to measure the biosignal. In this case, capacitive coupling is established between the biosignal acquisition unit 111 and the human body (living body) 1. As a result, a differential amplifier circuit is formed between the circuit of the measurement terminal 11_1 and the circuit of the other measurement terminal 11_2 via the human body (living body) 1, and signals other than DC components can be detected. Furthermore, the user can wear the measurement terminal 11 over the clothing 2 without having to put on or take off the clothing 2, improving convenience.

[0021] The terminal transmitter 114 may modulate the signal to efficiently use the human body (living body) 1 as a transmission path. Biological signals are typically sampled at 1 kHz or less for electrocardiograms and electroencephalograms, and at approximately 5 kHz or less for electromyograms. In this embodiment, interference between the biological signal and the transmission signal can be avoided by modulating at a higher frequency than these frequencies. Furthermore, by using a frequency (quasi-electrostatic field) with excellent transmission characteristics in the human body (living body) 1, approximately 1 MHz to 100 MHz, the modulated measurement signal can be efficiently transmitted within the human body (living body) 1. Furthermore, modulation methods such as AM modulation and FM modulation may be used. FM modulation is preferable because its transmission efficiency changes with human activity and is not affected by amplitude, as is the case with AM modulation. For modulation, a voltage-controlled oscillator (VCO) using a quartz crystal or varactor diode, a phase-locked loop (PLL) circuit, a multivibrator, or the like may be used.

[0022] The signal readout device 12 may be in direct or indirect contact with the human body (living body) 1. Here, when the signal readout device 12 is in indirect contact with the human body (living body) 1, it means that the signal readout device 12 is electrically connected by capacitive coupling via the clothing 2, the electrode coating, or the like. The signal readout device 12 may be placed in contact with the surface of the clothing 2, or may be placed in a pocket.

[0023] As described above, the signal readout device 12 receives the signal modulated by the measuring terminal 11. Therefore, the signal readout device 12 reads out the signal at a frequency (quasi-electrostatic field) of about 1 MHz to 100 MHz. This makes it possible to avoid interference between the measured biosignal and the readout signal, and to efficiently transmit the signal within the human body (living body) 1.

[0024] The signal readout device 12 may have an impedance near the readout electrode 122. Because the signal readout device 12 does not directly measure biosignals, it is sufficient to acquire only the transmission signal used for transmission and reception. The human body (living body) 1 can easily transmit (transmit) quasi-electrostatic fields, e.g., AC signals with frequencies of approximately 1 MHz to 100 MHz, and therefore can easily receive signals even through clothing 2. Assuming that the signal readout device 12 has a 1 cm square readout electrode 122 and transmits and receives signals through clothing 2 with a thickness of 1 mm, the capacitance formed between the signal readout device 12 and the human body (living body) 1 is approximately 1 pF, and the impedance at 10 MHz is approximately 16 kΩ. Therefore, by setting the input impedance of the signal readout device 12 to approximately 16 kΩ or several tens of times higher, for example, by setting the impedance to 10 kΩ or more and 100 kΩ or less, signal attenuation can be suppressed and reception can be suppressed.

[0025] The signal received by the signal readout device 12 is a signal obtained by modulating a biological signal, and is therefore demodulated by the readout receiving unit 121 and stored in the storage unit 123 .

[0026] When the transmission frequency differs for each measurement terminal 11, a bandpass filter corresponding to each frequency is used to limit the signal band input to each reading receiver 121, and the received (modulated) signal is demodulated, thereby making it possible to acquire a biological signal without using wireless communication such as BLE. Here, the reading receiver 121 of the signal reading device 12 may have a configuration similar to that of the terminal receiver 113 of the measurement terminal 11.

[0027] After demodulation or digital conversion, the data may be stored after undergoing signal processing.

[0028] 2, data may be converted into digital values ​​by an analog-to-digital converter (A / D converter) 124 or the like and then stored in a storage medium 3 such as an SD card or non-volatile memory, thereby enabling the device to be handy or portable.

[0029] Alternatively, when the signal readout device 12 is installed in a building or the like, the readout signal may be transmitted to an external storage medium or electronic device 4 via a network 5, as shown in Fig. 3. The network 5 may be a wired network (Internet, intranet, etc.) or a wireless communication network. Even when wireless communication is used, the number of pairings and the number of connected terminals can be reduced compared to when wireless communication is performed by each measurement terminal, and therefore bandwidth congestion and suppression of pairing are not hindered.

[0030] Furthermore, in the measurement system 10, the measurement terminal 11 no longer requires a wireless module, thereby significantly reducing power consumption. In the measurement terminal (wearable device) 11, wireless communication mainly accounts for the majority of power consumption. Therefore, by not using a wireless module, the measurement terminal (wearable device) 11 can be used for a long time. In addition, the battery capacity can be reduced, making the measurement terminal 11 lighter. This makes it possible to provide a measurement system that is highly convenient for users.

[0031] 4, the signal readout device 12 may further include an arithmetic circuit unit 125 to perform further circuit calculations on the received signal. The signal readout device 12 includes a readout electrode unit 122, two readout receiving units 121_1 and 121_2 connected to the readout electrode unit 122, and the arithmetic circuit unit 125 connected to the two readout receiving units 121_1 and 121_2. The storage unit 123 may be connected to the arithmetic circuit unit 125.

[0032] An example of the operation of the signal readout device 12 is described below: Two measuring terminals are configured to transmit and receive signals at different frequencies.

[0033] Modulated signals from the two measurement terminals are input to the readout electrode unit 122. A filter (not shown) arranged between the readout electrode unit 122 and the readout receiving units 121_1 and 121_2 branches the signal from one measurement terminal (one signal) and the signal from the other measurement terminal (the other signal) into the two readout receiving units 121_1 and 121_2, respectively.

[0034] The signals demodulated by the read receivers 121_1 and 121_2 (one signal and the other signal) are input to the arithmetic circuit unit 125. The arithmetic circuit unit 125 performs differential amplification on one signal as a positive-phase signal and the other signal as a negative-phase signal.

[0035] Common mode noise is superimposed on the signal transmitted from the measurement terminal. After the signal is demodulated by the readout receivers 121_1 and 121_2 of the signal readout device 12, the common mode noise is removed by a differential operation circuit (subtraction circuit), and only the desired biological signal can be read out.

[0036] When three or more measurement terminals are attached, for example, to save data for each limb lead in electrocardiogram measurement, three combinations are required so that the signal readout device 12 acquires potential differences from two of the left hand, right hand, and left foot. When acquiring these three patterns of potential differences, connecting the arithmetic circuit unit 125 makes it possible to remove common mode noise and output the limb leads, allowing data to be saved with high resolution. This allows for more precise analysis of biological signals, etc.

[0037] The measurement system and signal readout device according to this embodiment can receive and collect biosignals from a measurement terminal near a human body (living body) without using wireless communication such as BLE. This reduces the bandwidth required for transmitting and receiving biosignals within the measurement system, thereby preventing bandwidth congestion. Furthermore, pairing operations between multiple BLE devices are no longer necessary, improving usability and enabling comfortable health monitoring.

[0038] Second Embodiment A measurement system and a signal readout device according to a second embodiment of the present invention will be described with reference to FIGS. 5 and 6. FIG.

[0039] <Configuration of Measurement System and Signal Readout Device> Similar to the first embodiment, the measurement system according to this embodiment includes a plurality of measurement terminals and a signal readout device.

[0040] As shown in FIG. 5, the readout receiving section 121 in the signal readout device includes a demodulation circuit 1211 and a plurality of reception frequency setting sections 1212 .

[0041] In the readout receiving unit 121, demodulation of only one predetermined frequency band is performed at a predetermined time by switching between multiple receiving frequency setting units 1212 in a time-division manner using a switch 1213. By performing the switching operation in a short time, signals can be demodulated at multiple frequencies, and demodulated signals (dotted arrows in the figure) are output.

[0042] In the first embodiment, the number of read receivers required is equal to the number of measuring terminals, which results in an increase in power consumption and circuit area in the receiver circuit.

[0043] On the other hand, in this embodiment, signals from multiple measurement terminals are received at different frequencies by modulating the signals at different frequencies at each of the multiple measurement terminals. By using a common demodulation circuit 1211 and variably setting the frequency of the signal to be demodulated, signals from multiple measurement terminals can be demodulated by a single readout receiver 121. This reduces the power consumption of the receiver circuit and the circuit area.

[0044] 6 shows an example of a configuration applied to FM modulation of the read receiver 121 according to this embodiment. The read receiver 121 includes a phase detector / charge pump (PD / CP) 1214, an oscillator 1215, a filter 1216, and a plurality of voltage controlled resonant circuits 1217.

[0045] A modulated signal is input from the readout electrode section 122 to a phase detector / charge pump (PD / CP) 1214. A signal from an oscillator 1215 is also input to the PD / CP 1214.

[0046] The phases of both signals are compared by the PD / CP 1214, and the comparison result (phase difference) is output as a voltage from the charge pump. A low-frequency signal is obtained by passing the output voltage through a filter such as a loop filter.

[0047] This low-frequency signal is applied to the voltage-controlled resonant circuit 1217. The resonant frequency (set frequency) of the voltage-controlled resonant circuit 1217 changes in response to the applied voltage of the low-frequency signal, thereby changing the frequency of the oscillator 1215.

[0048] In the PD / CP 1214, when the frequency of the input signal from the oscillator 1215 matches the frequency of the received signal from the readout electrode 122, a low frequency signal is output as a demodulated signal (dotted arrow in the figure).

[0049] In this embodiment, the resonance point is voltage-controlled by applying demodulated signals to a plurality of voltage-controlled resonant circuits 1217, so that one voltage-controlled resonant circuit 1217 is always connected to the oscillator 1215. This allows a single receiving unit to demodulate a plurality of signals in a time-division manner, thereby reducing power consumption and circuit area.

[0050] In this embodiment, a switchable filter circuit, similar to the resonant circuit, may be arranged between the readout electrode 122 and the PD / CP 1214. This allows the received signal to be filtered in advance, thereby preventing locking at an unintended frequency. In this way, the demodulation operation can be stabilized. The switching frequency in this configuration is preferably equal to or higher than the required sampling rate of the biological signal being measured. For example, electrocardiograms require a sampling rate of approximately 100 to 1 kHz, so switching at a rate of 10 ms to 1 ms or more is desirable. Since electromyograms require faster sampling, such as 5 kHz, switching at a rate of 0.2 ms or more is desirable.

[0051] According to this embodiment, a single receiving unit in the signal readout device can receive and collect biosignals from a measurement terminal in the vicinity of a human body (living body) without using wireless communication such as BLE, thereby reducing the power consumption and circuit area of ​​the signal readout device.

[0052] Furthermore, it is possible to reduce the bandwidth required for transmitting and receiving biological signals within the measurement system 10, thereby suppressing bandwidth congestion. Furthermore, it is possible to eliminate the need for pairing operations between multiple devices such as BLE, improving usability and enabling health status monitoring to be achieved without discomfort.

[0053] <Third Embodiment> A measurement system according to a third embodiment of the present invention will be described with reference to Figures 7 to 10. In the measurement system according to this embodiment, the signal readout device according to the first embodiment or the signal readout device according to the second embodiment may be used.

[0054] <Configuration of the Measurement System> A handheld reading device may be used as an example of the measurement system according to this embodiment. As shown in FIG. 7 , a person other than the user, such as a medical professional (doctor or nurse), may hold the signal reading device 12 in their hand and bring it close to the user's body while wearing the measurement terminal 11. Because the signal reading device 12 is not affected by clothing, the user can wear the measurement terminal 11 in a predetermined position in advance to measure biosignals while wearing their clothes, ensuring privacy. For example, during a health checkup, other tests can be performed while wearing the measurement terminal 11, and an electrocardiogram can be measured during the waiting time, thereby improving work efficiency.

[0055] As another example of a measurement system, an environmentally-distributed measurement system may be configured to automatically read out signals by disposing a signal readout device 12 in a part of a building such as a house or a hospital, for example, on a floor 6 or a wall 7, as shown in Fig. 8. When a user wearing a measurement terminal 11 touches or approaches the signal readout device 12 installed on the floor or wall 7, a transmission signal emitted from the user's body may be received and a biosignal may be read out.

[0056] This allows the signal to be read automatically without the assistance of anyone other than the user when the measurement terminal 11 is worn by the user. For example, when the measurement terminals 11 are worn on both hands, the transmission signal propagates throughout the body, so the signal readout device 12 on the floor 6 may read the biosignal via the feet. When the measurement terminals 11 are worn on the feet or chest, the signal readout device 12 on the wall 7 may read the biosignal via another part of the body.

[0057] This allows signals to be collected without the user being aware of it, enabling long-term monitoring. At this time, the transmission signals of the measuring terminals 11 worn by each user are set to different frequencies, so users can be identified based on frequency information, thereby avoiding the risk of data confusion.

[0058] As another example of a measurement system, the signal readout device 12 may read signals using multiple readout electrode units 122. For example, as shown in FIG. 9 , multiple readout electrode units 122 may be arranged in an array in the signal readout device 12. The 1 MHz to 100 MHz frequency band (quasi-electrostatic field) used for signal transmission through the human body (living body) 1 is distributed only in the immediate vicinity of the transmission medium. Therefore, by arranging the readout electrode units 122 of the signal readout device 12 in an array, the signal amplitude transmitted to each readout electrode unit 122 can be monitored by each array, and the position of the array receiving the strongest signal can be determined as the user's position. In this way, the position of the user wearing the measurement terminal 11 can be obtained from the position of the readout electrode unit 122 that receives the biosignal among the multiple readout electrode units 122.

[0059] As another example of a measurement system, as shown in FIG. 10, multiple readout electrode units 122 of a signal readout device 12 may be placed at multiple positions on the floor 6, wall 7, etc., and the user's position may be determined by combining the signal strengths received by each readout electrode unit 122.

[0060] In the measurement system, the transmission signal is distributed locally, so that the signal is received with high signal strength only at the readout electrode unit 122 that is close to the user's position. The received signal strength decreases as the user's position moves away from the readout electrode unit 122. In the measurement system, the position of the readout electrode unit 122 where the signal is received with high signal strength may be determined to be the user's position.

[0061] For example, when a user moves away from the wall 7 on which the readout electrode 122 is located and moves to a location where the readout electrode 122 is located only on the floor 6, a signal (peak indicated by the dashed line in the figure) is read only from the readout electrode 122 located on the floor 6, resulting in a low readout signal strength. When a user moves near the wall 7 on which the readout electrode 122 is located and the floor 6, a signal (peak indicated by the dotted line in the figure) is read from the readout electrode 122 on the floor 6 and the readout electrode 122 on the wall 7, resulting in a high combined readout signal strength (peak indicated by the solid line in the figure). Furthermore, when a user uses a wheelchair, the measurement terminal 11 attached to the user's foot moves away from the floor 6, resulting in a low signal strength read from the readout electrode 122 on the wall 7. Furthermore, by placing at least one of the floor 6 and the wall 7 within a space where the user's location is to be determined, the signal strength can be used to determine whether the user is near the floor 6 or wall 7. Therefore, by placing multiple floors 6 and walls 7 within a space, the user's location can be determined without using GPS.

[0062] In this way, the position of the user wearing the measuring terminal 11 can be obtained from the strength of the signal obtained by combining the signals obtained by each of the plurality of readout electrode sections 122 .

[0063] Furthermore, in the measurement system, the distribution of signal levels changes as the user moves, allowing the user's location to be tracked over time. This allows the user's activity status to be monitored, which is useful for medical care, rehabilitation, etc. Furthermore, by visualizing the user's location, nurses and others can easily check the user's location information, making it easier to search for the user.

[0064] In the embodiments of the present invention, examples of the structure, dimensions, materials, etc. of each component in the configuration of the measurement system and signal readout device are shown, but the present invention is not limited to these examples. Any configuration may be used as long as the measurement system and signal readout device can exhibit their functions and effects.

[0065] It should be noted that the present invention is not limited to the above-described embodiments, and it is clear that many modifications and combinations can be made by a person having ordinary knowledge in the art within the technical concept of the present invention.

[0066] A part or all of the above-described embodiment or an example thereof can be described as, but is not limited to, the following supplementary notes.

[0067] (Supplementary Note 1) A measurement system comprising: a plurality of measurement terminals for measuring biosignals; and a signal readout device; the measurement terminals comprise a biosignal acquisition unit for acquiring biosignals, a terminal receiving unit, a receiving electrode unit connected to the terminal receiving unit, a terminal transmitting unit, and a transmitting electrode unit connected to the terminal transmitting unit; the signal readout device comprises a readout receiving unit and a readout electrode unit connected to the readout receiving unit; at least two of the plurality of measurement terminals form a differential amplifier circuit; the two measurement terminals are electrically connected via a living body; the biosignal is transmitted from the terminal transmitting unit of one of the two measurement terminals and received by the terminal receiving unit of the other measurement terminal; and when the readout electrode unit is positioned so as to be in direct contact with the living body or so as to be electrically connected by capacitive coupling, the readout receiving unit reads out the biosignal from the measurement terminal in a quasi-electrostatic field.

[0068] (Appendix 2) A measurement system as described in Appendix 1, which includes a plurality of readout electrode units and obtains the position of the user wearing the measurement terminal from the position of the readout electrode unit that receives the biological signal among the plurality of readout electrode units.

[0069] (Appendix 3) A measurement system as described in Appendix 1, which includes a plurality of readout electrode units and acquires the position of the user wearing the measurement terminal from the strength of a signal obtained by combining the biosignals acquired by each of the plurality of readout electrode units.

[0070] (Appendix 4) A signal reading device that reads out biosignals from at least two measurement terminals, among a plurality of measurement terminals, which have a terminal transmitting unit that measures the biosignals and transmits the biosignals via a transmitting electrode unit, and which form a differential amplifier circuit via a living body, and which comprises a readout receiving unit and a readout electrode unit connected to the readout receiving unit, and when the readout electrode unit is positioned so as to be in direct contact with the living body or so as to be electrically connected by capacitive coupling, the readout receiving unit reads out the biosignals from the measurement terminals in a quasi-electrostatic field.

[0071] (Supplementary Note 5) The signal readout device according to Supplementary Note 4, further comprising an impedance arranged in the vicinity of the readout electrode portion, the impedance being 10 kΩ or more and 100 kΩ or less.

[0072] (Supplementary Note 6) The signal readout device according to Supplementary Note 4 or Supplementary Note 5, further comprising an arithmetic circuit unit that reduces common-mode noise.

[0073] (Supplementary Note 7) The signal readout device according to any one of Supplementary Notes 4 to 6, wherein the readout receiving unit includes a single receiving circuit and switches the frequency of the readout biological signal by time division.

[0074] (Appendix 8) A signal reading device as described in Appendix 7, wherein the single receiving circuit comprises a demodulation circuit and a plurality of receiving frequency setting units, each of which sets a different receiving frequency, and by switching the connection between the demodulation circuit and one of the plurality of receiving frequency setting units, the demodulation circuit demodulates the read-out biological signal at a predetermined receiving frequency.

[0075] (Supplementary Note 9) A measurement system described in any one of Supplementary Note 1 to Supplementary Note 3, wherein each of the plurality of measurement terminals transmits and receives biological signals of different frequencies.

[0076] (Supplementary Note 10) The measurement system according to any one of Supplementary Note 1 to Supplementary Note 3 and Supplementary Note 9, wherein the measurement terminal includes a circuit unit, and the circuit unit performs differential amplification based on a signal obtained from the biological signal acquisition unit and a signal obtained from the terminal receiving unit.

[0077] (Supplementary Note 11) The measurement system according to any one of Supplementary Note 1 to Supplementary Note 3, Supplementary Note 9, and Supplementary Note 10, wherein the biological signal acquisition unit is arranged to be in direct contact with a living body or to be electrically connected to the living body by capacitive coupling, and acquires the biological signal.

[0078] (Supplementary Note 12) The measurement system according to any one of Supplementary Note 1 to Supplementary Note 3 and Supplementary Note 9 to Supplementary Note 11, wherein the terminal transmitting unit 114 modulates the biological signal with a quasi-electrostatic field.

[0079] The present invention can be applied to a measurement system for biological signals.

[0080] REFERENCE SIGNS LIST 10 Measurement system 11 Measurement terminal 111 Biosignal acquisition unit 113 Terminal receiving unit 114 Terminal transmitting unit 115 Receiving electrode unit 116 Transmitting electrode unit 12 Signal reading device 121 Reading receiving unit 122 Reading electrode unit

Claims

1. A measurement system comprising: a plurality of measurement terminals for measuring biosignals; and a signal readout device, wherein the measurement terminals comprise: a biosignal acquisition unit for acquiring biosignals, a terminal receiving unit, a receiving electrode unit connected to the terminal receiving unit, a terminal transmitting unit, and a transmitting electrode unit connected to the terminal transmitting unit, and the signal readout device comprises: a readout receiving unit and a readout electrode unit connected to the readout receiving unit, at least two of the plurality of measurement terminals form a differential amplifier circuit, and the two measurement terminals are electrically connected via a living body, the biosignal is transmitted from the terminal transmitting unit of one of the two measurement terminals and received by the terminal receiving unit of the other measurement terminal, and when the readout electrode unit is positioned so as to be in direct contact with the living body or so as to be electrically connected by capacitive coupling, the readout receiving unit reads out the biosignal from the measurement terminal in a quasi-electrostatic field.

2. The measurement system according to claim 1, comprising a plurality of said readout electrode units, and acquiring the position of the user wearing said measurement terminal from the position of the readout electrode unit among said plurality of said readout electrode units that receives said biosignal.

3. The measurement system according to claim 1, comprising a plurality of said readout electrode units, and acquiring the position of the user wearing the measurement terminal from the strength of a signal obtained by combining the biosignals acquired by each of said plurality of readout electrode units.

4. A signal readout device that reads out biosignals from at least two measurement terminals that form a differential amplifier circuit via a living body out of a plurality of measurement terminals, each having a terminal transmitter that measures the biosignal and transmits the biosignal via a transmitter electrode, the signal readout device comprising: a readout receiver; and a readout electrode unit that connects to the readout receiver; and when the readout electrode unit is positioned so as to be in direct contact with the living body or so as to be electrically connected by capacitive coupling, the readout receiver unit reads out the biosignal from the measurement terminal in a quasi-electrostatic field.

5. The signal readout device according to claim 4, further comprising an impedance arranged in the vicinity of said readout electrode portion, said impedance being 10 kΩ or more and 100 kΩ or less.

6. The signal readout device according to claim 4 or 5, further comprising an arithmetic circuit section for reducing common-mode noise.

7. A signal readout device according to claim 4 or claim 5, wherein the readout receiving section comprises a single receiving circuit, and the frequency of the readout biological signal is switched by time division.

8. A signal readout device as described in claim 7, wherein the single receiving circuit comprises a demodulation circuit and a plurality of receiving frequency setting units, wherein different receiving frequencies are set in the plurality of receiving frequency setting units, and wherein the demodulation circuit demodulates the readout biological signal at a predetermined receiving frequency by switching the connection between the demodulation circuit and one of the plurality of receiving frequency setting units.

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