Abstract:
A biological information acquisition telemetry system includes: a transmit device, attached to a part of a living body and configured to acquire a biological signal to transmit the biological signal as a radio signal; a relay device, configured to perform space diversity reception, the relay device including: a first receiver, configured to wirelessly receive the radio signal from the transmit device; a first transmitter, configured to transmit the radio signal received by the first receiver; and an attachment unit, adapted to hold the first receiver and the first transmitter and attach the first receiver and the first transmitter to the living body; and a center apparatus, including: a second receiver, configured to receive the radio signal from the first transmitter of the relay device; a processor, configured to generate biological information based on the radio signal received by the second receiver; and a display, configured to display the biological information generated by the processor.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates to a biological information acquisition telemetry system used to acquire biological information. 
         [0002]    A related-art system is a system of the type wherein each electrode for acquiring a signal from a living body is attached to the living body, a lead wire is extended from the electrode for introducing a biological signal into a radio relay device, and the biological signal is transmitted from the radio relay device to a center apparatus. 
         [0003]    However, in the related-art system, the electrode and the radio relay device are connected by the lead wire and thus if an attempt is made to obtain biological information of a subject in a moving state (for example, an exercise condition), the electrode is come off or contact of the electrode becomes unstable because of the length of the lead wire, and it becomes difficult to acquire stable biological information. Since the lead wire is placed so as to trail on the surface of the living body, the subject cannot do extreme exercise and insufficient biological information can only be acquired. 
         [0004]    A system described in JP-2007-143959 is known as a related-art system solving the problem described above. In the related-art system described in JP-2007-143959, a biological signal detected by a sensor is transmitted to a relay device through a wireless network and then is transmitted from the relay device to a center apparatus through the wireless network. 
         [0005]    However, this related-art system requires a wireless network and biological information cannot be acquired out of doors, where the wireless network is not provided. Generally, it is desirable to thin a sensor (reduce the thickness of the sensor from the body surface) for miniaturization and weight reduction. However, if the sensor is miniaturized and is reduced in weight, there is a problem in that a radio wave is absorbed in the living body and a biological signal cannot well be transmitted. 
         [0006]    Also in the relay device, a null point where the sensitivity of an antenna vanishes may occur depending on the positional relationship with the sensor or the distance between the antenna and the living body, a state in which a radio signal cannot be received appropriately, and it becomes necessary for the subject to do the same action, exercise, more than once as the position of the relay device is changed, to obtain a biological signal, leading to a heavy burden on the subject. 
       SUMMARY 
       [0007]    It is therefore an object of the invention to provide a biological information acquisition telemetry system for making it possible to miniaturize and reduce in weight a transmit device for acquiring a biological signal from a living body and acquire stable biological information while the transmit device allows a subject to do action and exercise sufficiently. 
         [0008]    In order to achieve the object, according to the invention, there is provided a biological information acquisition telemetry system comprising: 
         [0009]    a transmit device, attached to a part of a living body and configured to acquire a biological signal to transmit the biological signal as a radio signal; 
         [0010]    a relay device, configured to perform space diversity reception, the relay device comprising:
       a first receiver, configured to wirelessly receive the radio signal from the transmit device;   a first transmitter, configured to transmit the radio signal received by the first receiver; and   an attachment unit, adapted to hold the first receiver and the first transmitter and attach the first receiver and the first transmitter to the living body; and       
 
         [0014]    a center apparatus, comprising:
       a second receiver, configured to receive the radio signal from the first transmitter of the relay device;   a processor, configured to generate biological information based on the radio signal received by the second receiver; and   a display, configured to display the biological information generated by the processor.       
 
         [0018]    The transmit device may include a sensor configured to acquire the biological signal from the living body. 
         [0019]    The transmit device may be integrally provided with the sensor and an electrode for being in contact with a part of the living body. 
         [0020]    The relay device may include: two antennas; and spacers for placing the antennas with a distance from the living body. 
         [0021]    The transmit device may include an antenna having a loop shape and placed with a distance from the living body. 
         [0022]    The first receiver of the relay device may include: a first receiving portion and a second receiving portion, configured to receive the radio signal from the transmit device, respectively; and a processing portion, configured to compare electric field intensity of the radio signal received by the first receiving portion and electric field intensity of the radio signal received by the second receiving portion, and configured to adopt one of the radio signal received by the first receiving portion and the radio signal received by the second receiving portion which has the electric field intensity higher than that of the other. 
         [0023]    The first transmitter of the relay device may include an antenna having a shape of a quadratic curve away from a surface of the living body. A tip of the antenna may extend straightly from the surface of the living body. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]      FIG. 1  is a block diagram to show the configuration of a biological information acquisition telemetry system according to the present invention. 
           [0025]      FIG. 2  is a functional block diagram of a transmit device included in the biological information acquisition system. 
           [0026]      FIGS. 3A ,  3 B and  3 C are drawings to show the appearance of the transmit device;  FIG. 3A  is a front view;  FIG. 3B  is a rear view; and  FIG. 3C  is a bottom view. 
           [0027]      FIG. 4  is a sectional side view of the transmit device. 
           [0028]      FIG. 5  is a plan view of the transmit device in a state in which a chassis panel on the front of the transmit device is removed. 
           [0029]      FIG. 6  is a plan view of an electrode module for an electrocardiogram, connected to the transmit device. 
           [0030]      FIG. 7  is a sectional side view to show a transmit device of the type wherein no electrode is included on the back. 
           [0031]      FIG. 8  is a plan view of an angle sensor connected to the transmit device. 
           [0032]      FIG. 9  is a plan view of a respiratory waveform sensor connected to the transmit device. 
           [0033]      FIG. 10  is a plan view of an SpO2 transmit device included in the biological information acquisition telemetry system according to the invention and an SpO2 sensor connected to the SpO2 transmit device. 
           [0034]      FIGS. 11A and 11E  are perspective views to show the use state of the SpO2 transmit device and the SpO2 sensor. 
           [0035]      FIG. 12  is a plan view of a relay device included in the biological information acquisition telemetry system according to the invention. 
           [0036]      FIG. 13  is a plan view of the relay device in a state in which a front panel of a chassis of the relay device is removed. 
           [0037]      FIG. 14  is a functional block diagram of a part of the relay device. 
           [0038]      FIG. 15  is a functional block diagram of a part of the relay device. 
           [0039]      FIG. 16  is a front view of the relay device in a state in which an attachment unit is attached to the relay device. 
           [0040]      FIG. 17  is a perspective view of the relay device in a state in which a living body wears the relay device to which an attachment unit is attached. 
           [0041]      FIG. 18  is a perspective view of the relay device in a state in which a living body wears the relay device to which an attachment unit is attached. 
           [0042]      FIG. 19  is a drawing to show the transmission timings of a biological signal transmitted by the biological information acquisition telemetry system according to the invention. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0043]    A biological information acquisition telemetry system according to an embodiment of the invention will be discussed with reference to the accompanying drawings. Identical components in the accompanying drawings are denoted by the same reference numerals and duplicate description will not be given.  FIG. 1  shows the biological information acquisition telemetry system according to the embodiment of the invention. The biological information acquisition system includes transmit devices  100 , a relay device  200 , and a center apparatus  300 . 
         [0044]    As shown in  FIG. 2 , the transmit device  100  includes a sensor  102  for acquiring a biological signal by utilizing an electrode  101  to be in contact with a living body. If the transmit device  100  is a transmit device for detecting an electromyogram signal, or the like, the electrode  101  is integral with a chassis. 
         [0045]    The transmit device  100  includes an amplifier  103 , a CPU (Central Processing Unit)  104 , a CPLD (Complex Programmable Logic Device)  105 , a FSK (Frequency Shift Keying) transceiver  106 , and an antenna (internal lead wire antenna)  107  made of a lead wire. The circuit components receive a power from a power supply  100  having a battery (lithium ion battery) and containing a charging circuit. The amplifier  103  amplifies a biological signal sent from the sensor  102  and feeds the amplified biological signal into the CPU  104 . The CPU  104  converts the fed analog biological signal into a digital biological signal and sends the biological signal to the FSK transceiver  106  at a predetermined timing. The CPLD  105  reproduces a clock from a preamble pattern of reception data sent from the relay device  200  and feeds the clock into the CPU  104  for detecting the transmission timing. Here, TDMA (Time Division Multiple Access) is adopted and transmission is executed according to a preset time slot. 
         [0046]    The FSK transceiver  106  FSK-modulates sampling data of the biological signal sent from the CPU  104 , upconverts the signal into a predetermined radio frequency (medical radio E band), and transmits the signal from the antenna  107 . The FSK transceiver  106  also receives a radio signal sent from the relay device  200  through the antenna  107 , downconverts the signal, and sends the signal to the CPLD  105 . The FSK transceiver  106  can use two frequencies and transmits according to the setup one frequency. 
         [0047]    The transmit device  100  has the circuits, etc., housed in a chassis  110  shaped like a plane provided by joining a semicircle to a quadrangle as shown in  FIGS. 3A to 3C  and  4 . In the chassis  110 , a rechargeable battery  111  is placed at the center and an analog unit board  112  including the sensor  102 , the amplifier  103 , the power supply  108 , etc., is placed in the portion to the living body side from the battery  111  at the operating time. Further, an RF-CPU unit board  113  including the CPU  104 , the CPLD  105  and the FSK transceiver  106  is placed on opposite side to the analog unit board  112  with the battery  111  between. 
         [0048]    A board connection connector  114  for connecting the analog unit board  112  and the RF-CPU unit board  113  is placed therebetween. Further, an external connection connector  115  for connecting the electrode  101  provided on the outside of the chassis  110  is provided. Two antennas  107  each having a length of a quarter wavelength relative to a useful frequency are shaped like a loop along the margin of the chassis  110  on the top of the REF-CPU unit board  113 , the side at a distance from the living body, as shown in  FIG. 5 , which is a plan view of the transmit device  100  with the RF-CPU unit board  113  side of the chassis  110  opened, and the transmission distance is enhanced although the two antennas  107  are whip antennas. The two antennas  107  are fixed with an adhesive  116  at appropriate positions. 
         [0049]    There are types of transmit devices  100  having sensor functions for an electromyogram, an electrocardiogram, acceleration (uniaxial and triaxial), a DC (external input), an angle, a respiratory waveform, SpO2 (oxygen saturation of arterial blood), etc., and the electrode  101  and the sensor  102  are changed corresponding to each of the types. 
         [0050]    The transmit device  100  shown in  FIGS. 3A to 3C  and  4  is the type having the electromyogram sensor function, and three electrodes  101  project on a back  110 R of the chassis  110 . To use the transmit device  100 , double-side tape of the same shape as the back  110 R of the chassis  110 , formed with holes corresponding to the three electrodes  101  is attached on the back  110 R, the required parts of a living body are wiped with alcohol, and the back  110 R of the chassis  110  is attached on the living body with the double-side tape. The sensor  102  includes a related-art configuration for an electromyogram. 
         [0051]    The transmit device  100  for an electrocardiogram uses an electrode module provided by connecting three electrode terminals  120  to separate lead wires  121  and connecting the lead wires  121  to a plug  122  as shown in  FIG. 6 . The plug  122  is joined to the external connection connector  115  of the chassis  110 , the three electrode terminals  120  are jointed to the three electrodes (living body electrodes)  101  each having a conductive gel, etc., and the electrodes  101  are attached on the required positions of the chest of a living body. The transmit device  100  for an electrocardiogram is not provided with the electrodes  101  on the back  110  of the chassis  110  and has an almost flat face as shown in  FIG. 7 . Double-side tape of the same shape as the back  110 R of the chassis  110  is put on the back  110 R, the required parts of a living body are wiped with alcohol, and the back  110 R of the chassis  110  is put on the living body with the double-side tape. The sensor  102  includes a related-art configuration for an electrocardiogram. 
         [0052]    The transmit device  100  for acceleration (uniaxial and triaxial) includes a related-art sensor  102  containing an acceleration detection mechanism in the chassis  110 . An electrode for coming in contact with a living body does not exist. The transmit device  100  is not provided with the electrodes  101  on the back  110 R of the chassis  110  either and has a structure as shown in  FIG. 7 . To use the transmit device  100 , double-side tape of the same shape as the back  110 R of the chassis  110  is put on the back  110 R, the required parts of a living body are wiped with alcohol, and the back  110 R of the chassis  110  is attached on the living body with the double-side tape. 
         [0053]    The transmit device  100  for a DC introduces an external signal into the external connection connector  115  with an input cord and does not include the sensor  102 . An electrode for coming in contact with a living body does not exist. The back  110 R of the chassis  110  is as shown in  FIG. 7 . The use method is similar to that of the transmit device  100  for acceleration (uniaxial and triaxial). 
         [0054]    The transmit device  100  for an angle has two detectors  131  as shown in  FIG. 8  and uses a sensor to send a signal from the detector  131  through a lead wire  132  to a plug  133 . The plug  133  is joined to the external connection connector  115  of the chassis  110  and the two detectors  131  are put up and down or from side to side through a joint, whereby measurement is conducted. The transmit device  100  for an angle does not have an electrode for coming in contact with a living body. The back  110 R of the chassis  110  is as shown in  FIG. 7 . To use the transmit device  100 , double-side tape of the same shape as the back  110 R of the chassis  110  is put on the back  110 R, the required parts of a living body are wiped with alcohol, and the back  110 R of the chassis  110  is put on the living body with the double-side tape. 
         [0055]    The transmit device  100  for a respiratory waveform is provided with a detector  141  of a thermistor as shown in  FIG. 9 , for example, and uses a sensor to send a signal from the detector  141  through a lead wire  142  to a plug  143 . The sensor  102  takes out a signal for temperature change provided by the detector  141  of the thermistor. The transmit device  100  for a respiratory waveform does not have an electrode for coming in contact with a living body. The back  110 R of the chassis  110  is as shown in  FIG. 7 . To use the transmit device  100 , the detector  141  of the thermistor is fixed to the entrance of a nostril and the lead wire  142  is fixed to the face, etc., as required. Double-side tape of the same shape as the back  110 R of the chassis  110  is put on the back  110 R, the required parts of a living body are wiped with alcohol, and the back  110 R of the chassis  110  is put on the living body with the double-side tape. 
         [0056]    A sensor including a detector  151  having a light receiving element and a light transmitting element connected to a plug  153  through a lead wire  152  is connected to an external connection connector  115  of a transmit device  100 A for SpO2, for example, as shown in  FIG. 10 . The internal configuration of the transmit device  100 A is as shown in  FIG. 2 . A related-art configuration for SpO2 is used as a sensor  102 . The transmit device  100 A is housed in a housing case  162  attached to a head band  161  as shown in  FIGS. 11A and 11B  for use. The detector  151  is attached in the vicinity of the center of a forehead and is firmly bound with the head band  161 . A sheet fastener  163  is provided over a predetermined length from both ends of the headband  161 , and the transmit device  100 A housed in the housing case  162  is fixed to the back of a head, for example ( FIG. 11B ). 
         [0057]    The relay device  200  has a back along an R shape so as to be fitted to the abdomen or the lumbar area of a living body as shown in  FIG. 12 . In the center of the surface of the relay device  200 , two transmission boards  211  and a transmission-reception radio board  212  and a transmission-reception control board  213  of a two-layer structure are included in a box-like chassis  210  made flat, as shown in  FIG. 13 . 
         [0058]    The circuit configuration of the transmission-reception radio board  212  and the transmission-reception control board  213  is as shown in  FIG. 14 . The relay device  200  includes a first receiver  220 A and a second receiver  220 B for a space diversity reception technique. The first receiver  220 A and the second receiver  220 B are of the same configuration and therefore the first receiver  220 A will be discussed as a representative. The first receiver  220 A includes a reception antenna  221 A of a λ/4 dipole antenna made of a lead wire and a low-noise amplifier  222 A and inputs and amplifies a radio signal. 
         [0059]    Output of the low-noise amplifier  222 A is branched to BPFs (band pass filters)  224 A and  225 A by a divider  223 A. The BPFs  224 A and  225 A correspond to two used radio frequencies and allow different predetermined frequency components to pass through. 
         [0060]    Outputs of the BPFs  224 A and  225 A are fed into FSK transceivers  226 A and  227 A and are downconverted and FSK-demodulated and are sent to a CPLD  228 . The CPLD  228  performs processing of comparing the electric field intensities of the reception signals received from the first receiver  220 A and the second receiver  220 B and adopting the reception signal of the higher electric field intensity and in addition, reproducing a reception clock from a preamble pattern of the reception signal, etc. 
         [0061]    A first CPU  231  and a second CPU  232  are connected to the CPLD  228 . The first CPU  231  performs operation control of the  5  elements in the relay device  200  and the second CPU  232  performs TDMA reception processing in cooperation with the CPLD  228 . Here, for example, dual partitioning of eight time slots about one frequency is executed; a signal can be received from eight transmit devices  100  about one frequency and with two frequencies, a signal can be received from  16  transmit devices  100 . 
         [0062]    The circuit components receive a power from a power supply  236  having a battery (lithium ion battery)  235 . The signal received from the CPLD  228  and a receiver synchronous pattern and a status indicating the state of the apparatus to be set in a preamble pattern are sent to the two transmission boards  211 . Transmission circuits provided in the two transmission boards  211  are of the same configuration and are shown in  FIG. 15  although they differ in used transmission frequency. 
         [0063]    That is, the signal sent from the CPLD  228  arrives at an FSK transceiver  241  and a CPU  242  controls the FSK transceiver  241  so as to transmit signals received from the eight transmit devices  100  by conducting TDMA communications. The FSK transceiver  241  performs FSK modulation and up-conversion and each signal is transmitted from a transmission antenna  243  of a λ/4 dipole antenna made of a lead wire. 
         [0064]    The relay device  200  is provided on a top board with a power switch  251 , a check LED  252 , a check switch  253 , a transmission power changeover switch  254 , and a mark switch  255  as shown in  FIG. 12 . The user can know an operable state by turning on the power switch  251  and operating the check switch  253  to light the check LED  252  green. The mark switch  255  is operated, whereby a reception event can be caused to occur in an operation state for executing reception. 
         [0065]    The chassis  210  of the relay device  200  is formed on both sides with belt holes  209  shown in  FIG. 13  and belts  261  and  262  are attached to the belt holes  209  as shown in  FIGS. 16 to 18 . A reception stopper  263  and an insertion stopper  264  each having a length adjustment part are provided at the tips of the belts  261  and  262 . The belts  261  and  262  are provided with L-shaped antenna bags  265 . Each of the antenna bags  265  is a bag with a corner of the L letter formed as an entrance, and a spacer  266 made of an elastic body of sponge, etc., is contained in the bag. When a living body wears the relay device  200 , the reception antenna  221 A,  221 B is opposed to the surface of the living body with the spacer  266  between so that the reception antenna is placed with a distance from the surface of the living body. It was acknowledge by experiment that if the spacer  266  is more than 3 cm in thickness, preferred reception is made possible. 
         [0066]    Each of the belts  261  and  262  is provided with a belt hook  267  for fixing an antenna cord for connecting the reception antenna  221 A,  221 B and the low-noise amplifier  222 A,  222 B. Two transmission antennas  243  connected to the two transmission boards  211  project from both sides of the chassis  210  of the relay device  200  and are bent like a quadratic curve away from the surface of the living body with the tip of each antenna extending straightly from the surface of the living body. Accordingly, the degree of absorption of a transmitted radio signal in the living body is lowered and good transmission is made possible. A cushion  268  is put on the back of the relay device  200 . When a living body wears the relay device  200 , the cushion  268  is fitted to the living body and prevents large swinging caused by exercise, etc. The relay device  200  can also be used as it is put on the abdomen or the lumbar area of a living body as shown in  FIG. 13 ; the relay device  200  can also be used as it is removed from a living body with the belts  261  and  262  extended as shown in  FIG. 16 . 
         [0067]    As shown in  FIG. 1 , the center apparatus  300  includes an antenna  301 , a radio reception processor  302 , a central controller  303 , a display  304 , and an input  305 . The radio reception processor  302  receives a signal corresponding to two transmission frequencies of the relay device  200 , receives a TDMA communication signal, FSK-demodulates the signal to reproduce a biological signal corresponding to each time slot, and feeds the biological signal into the central controller  303 . 
         [0068]    The central controller  303  is a processor for processing the data of the biological signal, generating an electromyogram waveform, an electrocardiogram waveform, an acceleration waveform (uniaxial and triaxial), a DC waveform, an angle waveform, a respiratory waveform, an SpO2 waveform, etc., and displaying each waveform on the display  304 . The user can enter a command such as a display switch command given to the central controller  303  through the input  305 . The elements except the antenna  301  or the radio reception processor  302  can also be implemented as a personal computer, etc. 
         [0069]    In the biological information acquisition telemetry system described above, for example,  16  transmit devices for an electromyogram are provided as the transmit devices  100 , the eight transmit devices are set to those using a first frequency, and the remaining eight transmit devices are set to those using a second frequency. The time slots are allocated so that the time slots used for the eight transmit devices  100  using the first frequency do not overlap. The time slots are allocated so that the time slots used for the eight transmit devices  100  using the second frequency do not overlap. 
         [0070]    The transmit devices  100  are each powered on and are attached on the required parts of a living body as previously described. The relay device  200  with power on is set on the abdomen of the living body and measurement is started. Of course, the center apparatus  300  is also powered on and is placed in an operable state 
         [0071]    Each of the transmit devices  100  reproduces a clock from a preamble pattern contained in a transmission signal sent from the relay device  200  and detects the timing (position) of a synchronous signal at the top of the eight time slots. The synchronous signal SYN is reproduced as shown in  FIG. 19 . Since the time slots are allocated to the transmit devices  100 , each of the transmit devices  100  FSK-modulates the acquired biological signal for transmission at the predetermined manieth time slot from the pulse of the synchronous signal SYN. The biological signal is sent from each of the corresponding transmit devices  100  at time slots #T 1 , #T 2 , . . . , #T 8  in  FIG. 19 . 
         [0072]    The relay device  200  performs diversity reception of a coming radio signal, reproduces a reception clock from the preamble pattern of the reception signal, takes out the biological signal at each time slot, restores the signal to one frame of eight time slots, and adds a receiver synchronous pattern and a status indicating the state of the apparatus and transmits. 
         [0073]    The center apparatus  300  receives the biological signal placed at the eight time slots according to two frequencies, takes out the biological signal from the time slots using the receiver synchronous pattern, processes the data of the taken-out biological signal to generate an electromyogram waveform in response to the biological signal, and displays the electromyogram waveform on the display  304 . 
         [0074]    Thus, according to the embodiment, the biological signal is transmitted from the transmit device  100  to the relay device  200 , whereby the subject can do exercise, etc., as desired in a state in which the subject wears the transmit device  100  and the relay device  200 , and biological information in a moving state can be acquired. In this case, the two antennas  107  of the transmit device  100  are shaped like a loop along the margin of the chassis  110  on the top of the RE-CPU unit board  113 , the side at a distance from the living body, and the transmission distance is enhanced for contributing to reliable transmission of the biological signal. 
         [0075]    In the relay device  200 , space diversity reception is performed, the reception antenna  221 A,  221 B is opposed to the surface of the living body with the spacer  266  between so that the reception antenna is placed with a distance from the surface of the living body to enable preferred reception, and biological information can be reliably acquired. Further, the TDMA communication system is adopted, so that the biological signals can be acquired at a time from the transmit devices  100 , the biological signals in the parts or the biological signals according to a plurality of parameters can be obtained, and the activity state of the living body can be analyzed. 
         [0076]    In the biological information acquisition telemetry system according to an aspect of the invention, the biological signal acquired by the sensor is transmitted as a radio signal from the transmit device, the radio signal is received in the relay device according to the space diversity reception system, and the received signal is relayed and transmitted through the radio line, so that the receiver sensitivity of the signal transmitted from the transmit device in the relay device becomes high and it is made possible to acquire biological information appropriately. 
         [0077]    In the biological information acquisition telemetry system according to an aspect of the invention, the transmit device includes the electrode for coming in contact with the living body and the sensor in one piece, so that noise to the biological signal obtained from the electrode does not superpose through the lead wire and can be decreased and stable biological information can be acquired. 
         [0078]    In the biological information acquisition telemetry system according to an aspect of the invention, the relay device further includes two antennas for performing space diversity reception and the spacer for placing the antennas with a distance from the living body, so that it is made possible to receive a radio signal and stable biological information can be acquired. 
         [0079]    In the biological information acquisition telemetry system according to an aspect of the invention, the antenna provided with the transmit device is shaped like a loop on the side with a distance from the living body, so that a transmission radio wave is hard to absorb in the living body and stable biological information can be acquired.