Biological signal transmission apparatus

An electrode 4 for detecting a biological signal and a loop antenna 3 are integrally mounted on a support 2 placed on the surface of a living body and a transmitter 5 is placed on the support 2. A biological signal detected on the electrode 4 is input through a connector 11 to electric circuitry 10 of the transmitter 5 and an electric signal processed by the electric circuitry 10 is output through connectors 12 and 13 to both ends of the loop antenna 3 from which the biological signal is emitted to a receiver. At this time, the opening face of the loop antenna 3 is in a direction almost perpendicular to the surface of a living body for improving sensitivity.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a biological signal transmission apparatus of a 
medical telemeter for transmitting a biological signal from a transmitter 
through an antenna to a receiver and in particular to a biological signal 
transmission apparatus using a loop antenna, a microstrip antenna as an 
antenna. 
2. Related Art 
A system for transmitting by radio a biological signal detected on an 
electrode placed on a subject to a nearby computer diagnostic apparatus, 
etc., via an antenna for diagnosis is known. Hitherto, various 
propositions have been made as a transmission apparatus used with such a 
system. 
In a proposition described in JP-A-60-97103U, two electrodes 502 and 503 
attached to a chest belt 501 and a transmitter main unit 504 placed on a 
wrist of a subject are connected by electrode leads 505 and 506, as shown 
in FIG. 34. An antenna line 507 from the transmitter main unit 504 is 
placed closely on the leads 505 and 506 in parallel therewith and an end 
of the antenna line 507 is buried in the chest belt 501. The electrode 
leads 505 and 506 and the antenna line 507 are insulated from each other 
and the end of the antenna line 507 is also electrically insulated so as 
not to touch the body surface of the subject. 
According to the proposition, the antenna line 507 is placed closely on the 
leads 505 and 506 and thus can be made 1 m or longer without disturbing 
any motion, and the efficiency of the transmitter 504 can be improved and 
miniaturized for enhancing portability of the transmitter. 
In a proposition described in JP-A-62-202804U, a pair of electrodes 201 and 
202 is placed in unit cases 203 and 204, which are opened at bottoms for 
exposing the electrodes 201 and 202, and both ends of an antenna line 205 
are connected to the electrodes 201 and 202, as shown in FIG. 35. The unit 
cases 203 and 204 are coupled by a connection cable 206 and the antenna 
line 205 is inserted into the connection cable 206. 
According to the proposition, the electrodes 201 and 202 placed in a pair 
of unit cases 203 and 204 are fitted to a heart rate detection part of a 
living body and a signal from the antenna line 205 is transmitted, so that 
the device is easily attached and detached and moreover can be placed 
without an oppressive feeling or a feeling of wrongness on the chest of 
the subject. 
In a proposition described in JP-A-63-32501U, a device comprises a pair of 
electrodes 301 and 302, a transmitter main unit 303 having electric 
circuitry for processing an electrocardiographic signal detected on the 
electrodes 301 and 302, and an antenna 304 for sending the resultant 
signal to a receiver by a radio wave, as shown in FIG. 36. The antenna 304 
is covered with water-repellent fibers and is put on the surface of a 
human body. 
According to the proposition, the antenna 304 is covered with 
water-repellent fibers and is connected to the transmitter main unit 303 
so that it is put on the surface of a human body. Thus, when the device is 
attached to a subject, clothes of the subject do not swell locally and 
moreover it is not feared that the electrode 301, 302 may be off the 
attachment point. Resultantly, sufficiently strong radio waves can be sent 
to the receiver in addition to ease of use. 
In a proposition described in JP-A-9-108194, a base sheet 401 placed on the 
anterior chest wall of a subject is formed like an L letter, a longwise 
portion 401a is put along the breast bone line of the subject, and a 
widthwise portion 401c is directed toward the heart side from a corner 
401b positioned near the xiphisternum of the subject, as shown in FIG. 37. 
The base sheet 401 is formed on a rear with an adhesion layer made to 
adhere to the anterior chest wall. A first electrode 402 is attached in 
the proximity of the corner 401b, a second electrode 403 is attached in 
the proximity of the upper end part of the longwise portion 401a, and a 
third electrode 404 is attached in the proximity of a side end part of the 
widthwise portion 401c. Further, a fourth electrode 405 is attached 
slantingly below the second electrode 403 and a fifth electrode 406 is 
attached above the third electrode 404. 
Of the five electrodes arranged as described above, .alpha. induction is 
detected between the electrodes 402 and 403 and .beta. induction is 
detected between the electrodes 403 and 404. .gamma. induction for 
ischaemia of side and front and rear walls in a high-potential direction 
weak in sensitivity only with .alpha. induction and .beta. induction is 
detected by means of the electrodes 405 and 406. The electrocardiographic 
signals induced to the electrodes are amplified and modulated by a circuit 
unit 407 attached to the base sheet 401 and are transmitted to the 
receiver through an antenna 408 attached along the longwise portion 401a. 
According to the proposition, the electrodes 402 to 406, the circuit unit 
407, and the antenna 408 are mounted integrally on the base sheet 401, so 
that the device is easily placed on the subject and action is not limited. 
In the examples in the related arts described above, the antennas are 
monopole antennas using the electricity length of a quarter the wave 
length. For example, assuming that the transmission frequency is 300 MHz, 
the wave length is 1 m and the antenna length becomes 25 cm. To place the 
monopole antenna so that it is not affected by a human body as much as 
possible, the monopole antenna may be placed in a direction perpendicular 
to the surface of a human body and distant from the human body. However, 
the antenna length is long (in this case, 25 cm), thus when the 
transmitter is placed on a human body, it disturbs the motion of the human 
body. If the transmitter is placed along the surface of the human body so 
as to facilitate the motion, radio waves radiated from the antenna are 
affected by the human body as described above, thus the gain is easily 
degraded. Also, although employing small and compact transmitter and 
electrode, there is still a problem that long using for standard limb lead 
(II) between electrodes disturb patient. 
SUMMARY OF THE INVENTION 
It is therefore an object of the invention to provide a small-sized 
biological signal transmission apparatus that can emit a biological signal 
detected on an electrode placed on the surface of a living body to a 
receiver with stable and good sensitivity and can be easily placed on the 
living body. 
According to an aspect of the present invention, there is provided a 
biological signal transmission apparatus comprising an electrode for 
detecting a biological signal, a support for supporting the electrode, the 
support being placed on a living body surface, a transmitter having 
electric circuitry for processing the biological signal detected on the 
electrode, and at least one loop antenna for emitting the biological 
signal processed by the electric circuitry to a receiver, the loop antenna 
being disposed so that an opening face is placed in a direction almost 
perpendicular to the living body surface. 
According to another aspect of the present invention, there is provided a 
biological signal transmission apparatus comprising an electrode for 
detecting a biological signal, a support for supporting the electrode, the 
support being placed on a living body surface, a transmitter having 
electric circuitry for processing the biological signal detected on the 
electrode, and two loop antennas for emitting the biological signal 
processed by the electric circuitry to a receiver, the loop antennas being 
disposed so that opening faces are placed in a direction almost 
perpendicular to the living body surface and are almost at right angles to 
each other. 
According to another aspect of the present invention, in the biological 
signal transmission apparatus, at least one of the loop antennas is 
contained in the transmitter. 
According to another aspect of the present invention, in the biological 
signal transmission apparatus, at least one of the loop antennas is 
divided into two parts, one loop antenna division part is placed in the 
support and the other is placed in the transmitter, and the transmitter is 
placed on the support, thereby putting the loop antenna division parts 
into one piece. 
According to another aspect of the present invention, in the biological 
signal transmission apparatus, the loop antenna is integral with the 
support and is connected at both ends to output of the electric circuitry 
through connection members and the transmitter is placed on the support. 
According to another aspect of the present invention, there is provided a 
biological signal transmission apparatus comprising an electrode for 
detecting a biological signal, a support for supporting the electrode, the 
support being placed on a living body surface, a transmitter having 
electric circuitry for processing the biological signal detected on the 
electrode, at least one loop antenna for emitting the biological signal 
processed by the electric circuitry to a receiver, the loop antenna being 
disposed so that an opening face is placed in a direction almost 
perpendicular to the living body surface, and a microstrip antenna having 
a radiation plate and a base plate opposed in parallel with the living 
body surface, the base plate being placed nearer to the living body 
surface. 
According to another aspect of the present invention, there is provided a 
biological signal transmission apparatus comprising an electrode for 
detecting a biological signal, a support for supporting the electrode, the 
support being placed on a living body surface, a transmitter having 
electric circuitry for processing the biological signal detected on the 
electrode, two loop antennas for emitting the biological signal processed 
by the electric circuitry to a receiver, the loop antennas being disposed 
so that opening faces are placed in a direction almost perpendicular to 
the living body surface and are almost at right angles to each other, and 
a microstrip antenna having a radiation plate and a base plate opposed in 
parallel with the living body surface, the base plate being placed nearer 
to the living body surface. 
In the biological signal transmission apparatus of the present invention, 
at least one of the loop antennas and the microstrip antenna is contained 
in the transmitter. 
In the biological signal transmission apparatus of the present invention, 
at least one of the loop antennas and the microstrip antenna is integral 
with the support and the loop antenna or the microstrip antenna is 
connected to output of the electric circuitry through a connection member 
and the transmitter is placed on the support.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the accompanying drawings, there are shown preferred 
embodiments of a biological signal transmission apparatus of the 
invention. FIG. 1 is a block diagram to show a configuration example of a 
first embodiment of the invention. FIG. 2 is a longitudinal sectional view 
to show the configuration of a living body placement section in FIG. 1. 
FIG. 3 is an exploded perspective view of the living body placement 
section shown in FIG. 2. FIG. 4 is an external perspective view of the 
living body placement section and a transmitter in FIG. 1. 
In FIG. 1, a living body placement section 1 comprises a loop antenna 3 and 
an electrode 4 integrally mounted on a flat support 2 formed of an 
insulating material. A transmitter 5 comprises electric circuitry 10 made 
up of an amplification section 6, a modulation section 7, a power supply 
section 8, and a transmission section 9. The electrode 4 and the 
amplification section 6 and the loop antenna 3 and the transmission 
section 9 are electrically connected through connectors 11, 12, and 13. 
Numeral 14 is an electrode placed on another part of a living body. The 
electrode 14 is connected to the amplification section 6 by a connector 
15. 
Power is supplied from the power supply section 8 to the amplification 
section 6, the modulation section 7, and the transmission section 9. When 
the support 2 is placed on the living body surface of a subject, a 
biological signal detected on the electrode 4 is amplified by the 
amplification section 6 and is modulated by the modulation section 7, then 
is sent from the transmission section 9 to the loop antenna 3. The 
biological signal is transmitted by radio from the loop antenna 3 to a 
receiver (not shown). 
In FIG. 2 and FIG. 3, the support 2 is formed of an insulating material 
like a square plate. The loop antenna 3 formed of a conductive material 
like a belt is placed along one side of the lower face of the support 2 
and the loop antenna 3 is folded at both ends back to the upper face of 
the support 2 so as to sandwich the support 2. Convex hooks 16 and 17 
forming a connector are fixed at both ends of the loop antenna 3. 
The electrode 4 passes through the support 2 from the lower face thereof, 
projects upward, and is fixedly secured in the portion of the support 2 
where the loop antenna 3 is not placed. Conductive water-containing gel 18 
is applied to the lower end face of the electrode 4. A hook 19 is attached 
to one end of the electrode 4 passing through the support 2 from the lower 
face thereof and projecting upward. An insulating sheet 20 covering the 
loop antenna 3 is bonded to the full lower face of the support 2 and the 
electrode 4 is exposed to the lower face through a hole 20a made in the 
insulating sheet 20. An adhesive 21 is applied to the lower face of the 
insulating sheet 20. The upper face of the support 2 is also covered with 
an insulating sheet 22 and the hooks 16, 17, and 19 pass through the 
insulating sheet 22 and project upward. 
The transmitter 5 is placed on and fixed to the described living body 
placement section 1, as shown in FIG. 4. At this time, the hooks 16, 17, 
and 19 are connected to the corresponding connectors (not shown) of the 
transmission section 9 and the amplification section 6 in the transmitter 
5. As shown in FIG. 30, when the living body placement section 1 is bonded 
to the surface of the living body of a subject via the adhesive 21, a 
biological signal detected on the electrode 4 is sent through the hook 19 
to the transmitter 5 and is processed by the electric circuitry 10 in the 
transmitter 5, then is sent through the hooks 16 and 17 to the loop 
antenna 3 from which the biological signal is transmitted to the receiver 
(not shown) by radio. 
First Embodiment 
Next, specific structures and materials of the parts of the first 
embodiment shown in FIG. 1 to FIG. 4 will be discussed in detail. The 
support 2 is several ten .mu.m to several mm thick, for example, and has 
reasonable rigidity for holding the living body placement section 1. In 
the above-described example, the support 2 is shaped like a square plate, 
but may be of any shape like a center-constricted plate, for example, as 
shown in FIG. 5. For example, the support 2 is formed of a material of 
paper or a macromolecular dielectric substance, such as vinyl chloride, 
polyurethane, polystyrene, polycarbonate, polypropylene, fluororesin, 
silicone resin, cellulose acetate, polyester, rayon, nylon, vinylon, epoxy 
resin, or ceramics. 
The loop antenna 3 is several .mu.m to several mm thick, for example, has a 
surrounding length of about several times the wavelength about a several 
tenths of the wave length, and is formed of an elongated conductive film. 
The planar shape is not limited; for example, the loop antenna 3 may be 
narrow as shown in FIG. 6 or may be wide as shown in FIG. 7. For example, 
metal, carbon, amacromolecular conductive substance, or resin to which 
conductive plating is given is used as the material of the loop antenna 3. 
The electrode 4 is fixed to the support 2 through the connector 11, is a 
conductive substance itself, and acts as an electrode for deriving a 
living body electricity phenomenon. It may be of any structure if it can 
be stably fixed to the hook 19 as the connector, for example, as shown in 
FIG. 8. The material of the electrode 4 may be a conductive substance 
similar to connector described later, and is not limited. For example, a 
macromolecular conductive substance, such as conductive rubber or 
water-containing resin, metal, such as copper, stainless steel, or 
aluminum, carbon, such as carbon fibers or graphite, resin to which 
conductive plating is given (for example, a conductive metal film of gold, 
silver, copper, nickel, aluminum, palladium, platinum, etc., is formed on 
the surface of a macromolecular insulating substance or a macromolecular 
conductive substance by means of sputtering evaporation, electrolytic 
plating, electroless plating, etc.,) is used as the material of the 
electrode 4. 
The water-containing gel 18 makes electric conduction between the electrode 
4 and a living body surface and preferably it has adhesion to aliving 
body. For example, gelatin, polyacrylic acid, its salt, karaya gum, any 
other water-soluble or water-dispersable acrylic-family polymer, 
water-soluble or water-dispersable polymer of polyacrylamide, polyvinyl 
alcohol, carboxymethyl cellulose, polyurethane, etc., or the like can be 
named as the base material for forming the gel layer. 
In the above-described example, the hooks 16, 17, and 19 are used as the 
parts forming the connectors 11, 12, and 13, but the scope of the 
invention is not limited to them. For example, a structure of a 
general-purpose electric connector, a contact-type connector, etc., may be 
used. A material similar to that of the electrode 4 described above can be 
used. 
The insulating sheets 20 and 22 are provided so that a human body and the 
loop antenna 3 do not come in direct contact with each other. They may be 
made of any material if the material has an insulating property; the 
material is not limited. 
The adhesive 21 is provided for strongly fixing the living body placement 
section 1 to a living body; preferably it is a substance not giving an 
impetus to the living body. For example, a known adhesive material 
excellent in intimate contact with the living body placement section 1, 
such as double-sided adhesive tape, an acrylic family, a rubber family, or 
a vinyl ether family, can be used. 
According to the embodiment, the loop antenna 3 is placed near the surface 
of a living body through the support 2 and moreover the opening face of 
the loop antenna 3 is almost at right angles to the living body surface, 
so that the sensitivity can be improved and the gain can be increased 
because of the known loop antenna characteristics. 
Second Embodiment 
FIG. 9 to FIG. 11 show a configuration example of a second embodiment of 
the invention. Parts identical with or similar to those previously 
described with reference to FIG. 1 to FIG. 4 are denoted by the same 
reference numerals in FIG. 9 to FIG. 11 and will not be discussed again in 
detail. 
In the second embodiment, the number of electrodes 4 is two and biological 
signals detected on electrodes 4a and 4b are sent through connectors 11a 
and 11b to an amplification section 6, as shown in FIG. 9. Other 
components and functions are almost similar to those of the first 
embodiment previously described with reference to FIG. 1 to FIG. 4. 
FIG. 10 is an exploded perspective view to show a configuration example of 
a living body placement section 1 and a transmitter 5 in FIG. 9. FIG. 11 
is an external perspective view of the living body placement section 1 and 
the transmitter 5 in FIG. 9. In FIG. 10, ends of conductive terminals 18c 
and 18d disposed on the lower face of a support 2 are electrically 
connected to caulking devices 31a and 31b respectively, and conductive 
water-containing gels 18a and 18b are attached to opposite ends of the 
conductive terminals 18c and 18d. The caulking devices 31a and 31b pass 
through the support 2 and project upward and are fixed to the support 2 
together with the conductive terminals 18c and 18d. 
A loop antenna 3 is placed on the lower face of the support 2 between the 
conductive terminals 18c and 18d and is folded at both ends back to the 
upper face of the support 2 so as to sandwich the support 2. An insulating 
sheet 20 for covering the loop antenna 3, the caulking devices 31a and 
31b, and the conductive terminals 18c and 18d is bonded to the space 
between the conductive water-containing gels 18a and 18b on the lower face 
of the support 2, and an adhesive 21 is applied to the lower face of the 
insulating sheet 20. 
The upper face of the support 2 is also covered with an insulating sheet 
22. Convex hooks 19a and 19b placed at the upper ends of the caulking 
devices 31a and 31b and convex hooks 16 and 17 fixed to both ends of the 
loop antenna 3 pass through the insulating sheet 22 and project upward. A 
transmitter 5 is made up of an upper lid 40a and a lower lid 40b making up 
a cabinet 40, a board 41 housed therein, and electric circuitry 10 mounted 
on the board 41. The board 41 is formed on a surface with four lands 42 
connected to the electric circuitry 10. It is fixed to the lower lid 40b 
through the lands 42 by a caulking device 43 and a concave hook 44. Also 
in the embodiment, as shown in FIG. 11, the transmitter 5 is placed on and 
fixed to a living body placement section 1 through the convex hooks 16, 
17, 19a, and 19b and the concave hook 44, and the functions and advantages 
similar to those of the first embodiment previously described with 
reference to FIG. 1 to FIG. 4 can be provided. The structures and 
materials of the members shown in FIG. 9 to FIG. 11 are almost similar to 
those of the first embodiment previously described with reference to FIG. 
1 to FIG. 4. 
In the second embodiment, the number of the electrodes 4 is two, but three 
or more electrodes 4 may be used. In this case, the electrodes 4 are 
placed at appropriate positions of the living body placement section 1 and 
are related to the connectors 11 and the amplification section 6 and a 
modulation section 7 in the electric circuitry 10, whereby a large number 
of biological signals can be derived and amplified, then transmitted from 
a transmission section 9, needless to say. 
As shown in FIG. 12, the electrodes 4 are replaced with a transducer 23, 
whereby the temperature, blood pressure, etc., of a living body can also 
be detected. 
Third Embodiment 
FIG. 13 is a longitudinal sectional view to show a configuration example of 
a third embodiment of the invention. Parts identical with or similar to 
those previously described with reference to FIG. 1 to FIG. 4 are denoted 
by the same reference numerals in FIG. 13 and will not be discussed again 
in detail. The third embodiment is characterized by the fact that a part 
of a loop antenna 3 is formed according to a thin film technology of silk 
print, etc. As shown in FIG. 13, through holes are made near two opposed 
sides of a support 2 and are filled with conductive material 24. The 
support 2 is formed on both faces with conductive thin films 25 according 
to the thin film technology and the upper conductive thin film 25 is 
divided into two portions. The upper and lower conductive thin films 25 
are electrically connected at both ends to the conductive material 24 with 
which the through holes are filled, forming the loop antenna 3. 
The upper and lower faces of the support 2 are covered with insulating 
sheets 20 and 22 for covering the conductive thin films 25 and the upper 
insulating sheet 22 is cut at the center for exposing the conductive thin 
film 25 at both ends thereof. When a transmitter 5 is placed on a living 
body placement section 1, a pair of conductive contact connectors 26 
projecting from the lower face of the transmitter 5 abuts the exposure 
parts of the conductive thin film 25 at both ends thereof for introducing 
a signal transmitted from the transmitter 5 into the loop antenna formed 
of the conductive thin films 25. A hook 19 fixed to an electrode 4 is 
coupled to a connector 11 like a concave hook to the transmitter 5, as in 
the first embodiment. 
According to the third embodiment, the manufacturing process is simplified 
and costs can be reduced as compared with the case where the loop antenna 
3 is formed as a thin-film separate body and is folded at both ends back 
to the support 2 and fixed as in the configuration examples of the first 
and second embodiments. 
In FIG. 13, an embodiment configured to include one electrode 4 is shown, 
but the third embodiment can also be applied to the case where the number 
of the electrodes 4 is two or more as in the configuration example of the 
embodiment shown in FIG. 9 and FIG. 10 and the embodiment where the 
electrode 4 is the transducer 23 as shown in FIG. 12; similar advantages 
can be provided. 
Fourth Embodiment 
FIG. 14 is a block diagram to show a configuration example of a fourth 
embodiment of the invention. FIG. 15 is an exploded perspective view to 
show a specific configuration example of a living body placement section 
in FIG. 14. FIG. 16 is an external perspective view of the living body 
placement section shown in FIG. 14 and a transmitter placed thereon. FIG. 
17 is a plan view to show the form of a modified example of a support in 
FIG. 15. FIG. 18 is a drawing to show the attachment structure o f an 
electrode in FIG. 17. 
In FIG. 14, a living body placement section 101 comprises division parts 
103a and 104a of two antennas 103 and 104 each divided into two parts and 
two electrodes 105a and 105b mounted on a flat support 102 formed of an 
insulating material. In the embodiment, the antenna 103 is a loop antenna 
and the antenna 104 is a microstrip antenna (MSA). A transmitter 106 
comprises electric circuitry 111 made up of an amplification section 107, 
a modulation section 108, a power supply section 109, and a transmission 
section 110 and other division parts 103b and 104b of the two antennas 103 
and 104. The electrodes 105a and 105b and the amplification section 107 
are connected through connectors 112a and 112b, one end of the part 103a 
of the antenna 103 and one end of the part 103b of the antenna 103 are 
connected through a connector 113a, and the opposite end of the part 103a 
of the antenna 103 and the transmission section 110 are connected through 
a connector 113b. The opposite end of the part 103b of the antenna 103 is 
connected to the transmission section 110. The part 104a of the antenna 
104 (MSA) is a base plate and the part 104b of the antenna 104 is a 
radiation plate. The base plate 104a is connected to the transmission 
section 110 through a connector 114 and the radiation plate 104b is 
directly connected to the transmission section 110. 
Power is supplied from the power supply section 109 to the amplification 
section 107, the modulation section 108, and the transmission section 110. 
When the support 102 is placed on the living body surface of a subject, 
biological signals detected on the electrodes 105a and 105b are amplified 
by the amplification section 107 and are modulated by the modulation 
section 108, then are sent from the transmission section 110 to the 
antennas 103 and 104. The biological signals are transmitted by radio from 
the antennas 103 and 104 to a receiver (not shown). 
In FIG. 15 and FIG. 16, the support 102 is formed of a dielectric material 
like a rectangular plate. The loop antenna 103 formed of a conductive 
material like a belt is divided into two parts. One loop antenna part 103a 
is placed on one side of the lower face of the support 102 and caulking 
devices 115a and 115b are inserted into both ends of the loop antenna part 
103a. The caulking devices 115a and 115b pass through the loop antenna 
part 103a from the lower face thereof and further pass through the support 
102 and project upward. Hooks 116a and 116b are fixed to the projection 
ends of the caulking devices 115a and 115b by caulking. The loop antenna 
part 103b is connected at one end to the hook 116a. The hook 116b is 
connected to the transmission section 110. 
As described above, the MSA 104 consists of the base plate 104a and the 
radiation plate 104b, which are opposed to each other in parallel. As 
shown in FIG. 15, the base plate 104a is fixed almost at the center of the 
lower face of the support 102 and is formed with a projection 141a at the 
center of one side opposite to the loop antenna part 103a. A caulking 
device 117 is inserted into the projection 141a; it passes through the 
base plate 114a from the lower face thereof and further passes through the 
support 102 and projects upward. A hook 118 for the base plate is fixed to 
the projection ends of the caulking device 117 by caulking. 
A pair of plate-like conductive terminals 121c and 121d is placed at both 
sides of the projection 141a of the base plate 104a in parallel with one 
side of the base plate 104a and are fixed to the lower face of the support 
102. Caulking devices 119a and 119b are inserted into opposed ends of the 
conductive terminals 121c and 121d; they pass through the conductive 
terminals 121c and 121d from the lower faces thereof and further pass 
through the support 102 and project upward. Hooks 120a and 120b for 
deriving electrocardiographic signals are fixed to the projection ends of 
the caulking devices 119a and 119b by caulking. Conductive 
water-containing gels 121a and 121b are attached to outer ends of the 
conductive terminals 121c and 121d. Further, the lower faces of the loop 
antenna part 103a, the base plate 104a, and the conductive terminals 121c 
and 121d are covered with an insulating sheet 122 and an adhesive 123 is 
applied to the lower face of the insulating sheet 122. 
The transmitter 106 is shaped like a square can as shown in FIG. 16 and 
contains a board (not shown) on which the electric circuitry 111 is 
mounted. On the board, the loop antenna part 103b and the radiation plate 
104b are placed at the positions corresponding to the loop antenna part 
103a and the base plate 104a in the living body placement section 101, as 
shown in FIG. 15. When the transmitter 106 is attached to the living body 
placement section 101, the hook 116a projecting from the top of the 
support 102 of the living body placement section 101 is fitted to one end 
of the loop antenna part 103b and the convex hooks 118, 120a, and 120b are 
connected to concave hooks 124, 125a, and 125b formed at predetermined 
positions of the board. The concave hooks 124, 125a, and 125b are 
connected to the electric circuitry 111. Further, the opposite end of the 
loop antenna part 103b is also connected to the electric circuitry 111. 
Next, specific structures and materials of the parts of the fourth 
embodiment shown in FIG. 14 to FIG. 18 will be discussed in detail. The 
support 102 is formed of a dielectric substance which is several ten .mu.m 
to several mm thick, for example, and has reasonable rigidity and 
dielectric constant for holding the living body placement section 101. In 
the above-described example, the support 102 is shaped like a rectangular 
plate, but may be of any shape like a hand drum, for example, as shown in 
FIG. 17. The support 102 may be formed of a material of a dielectric 
substance having a dielectric constant fitted to the use frequency and the 
shapes of the base plate 104a and the radiation plate 104b, for example, 
paper or a macromolecular dielectric substance, such as vinyl chloride, 
polyurethane, polystyrene, polycarbonate, polypropylene, fluoroplastics, 
silicone resin, cellulose acetate, polyester, rayon, nylon, vinylon, epoxy 
resin, or ceramics. 
The loop antenna 103 is several .mu.m to several mm thick, for example, has 
a surrounding length of about several times the wavelength to about 
several tenths of the wave length, and is formed of an elongated 
conductive film. The planar shape is not limited. For example, metal, 
carbon, a macromolecular conductive substance, or resin to which 
conductive plating is given is used as the material of the loop antenna 
103. 
The base plate 104a basically has a large area in the allowable range and a 
structure for making a signal emitted from the radiation plate 104b hard 
to be affected by a human body, etc. For example, metal, carbon, a 
macromolecular conductive substance, or resin to which conductive plating 
is given is used as the material of the base plate 104a. The shape of the 
base plate 104a also changes corresponding to the antenna characteristics. 
The radiation plate 104b is formed of a conductive film which is several 
.mu.m to several mm thick, for example, and has an area determined by 
frequency. In the above-described example, the radiation plate 104b is 
shaped like a rectangular plate, but may be of any shape. For example, 
metal, carbon, a macromolecular conductive substance, or resin to which 
conductive plating is given is used as the material of the radiation plate 
104b like the base plate 104a. 
The caulking devices 115a, 115b, 117, 119a, and 119b and the conductive 
terminals 121c and 121d are fixed to the support 102 through the hooks 
116a, 116b, 118, 120a, and 120b, are conductive substances themselves, and 
act as electrodes for deriving a living body electricity phenomenon and 
electrodes for transferring signals to the base plate 104a. They may be of 
any structure if it can be stably fixed to the hook 120 as the connector, 
for example, as shown in FIG. 18. The material may be a conductive 
substance and is not limited. For example, a macromolecular conductive 
substance, such as conductive rubber or water-containing resin, metal, 
such as copper, stainless steel, or aluminum, carbon, such as carbon 
fibers or graphite, resin to which conductive plating is given (for 
example, a conductive metal film of gold, silver, copper, nickel, 
aluminum, palladium, platinum, etc., is formed on the surface of a 
macromolecular insulating substance or a macromolecular conductive 
substance by means of sputtering evaporation, electrolytic plating, 
electroless plating, etc.,) is used as the material. 
In the above-described example, the hooks 116a, 116b, 118, 120a, and 120b 
are used as the parts forming the connectors 112c, 112d, 113c, 113d, and 
114, but the scope of the invention is not limited to them. For example, a 
structure of a general-purpose electric connector, a contact-type 
connector, etc., may be used. A material similar to that of the caulking 
devices 115a, 115b, 117, 119a and 119b described above can be used. 
The water-containing gel 121a, 121b makes electric conduction between the 
conductive terminal 121c, 121d and a living body surface and preferably it 
has adhesion to a living body. For example, gelatin, polyacrylic acid, its 
salt, karaya gum, any other water-soluble or water-dispersable 
acrylic-family polymer, polyacrylic-family polymer, water-soluble or 
water-dispersable polymer of polyacrylamide, polyvinyl alcohol, 
carboxymethyl cellulose, polyurethane, etc., or the like can be named as 
the base material for forming the gel layer. The length and breadth of the 
water-containing gels 121a, 121b to be attached to living body is the 
range from approximately 2 to 6 cm. But the shape of the water-containing 
gels are not limited as described shape, and any figure like a square, 
rectangle, circle, oval are applicapable. 
Preferably, the distance between nearest of water-containing gels 121a, 
121b is the range from approximately 1.0 to 7.5 cm to detect heat rate 
information and etc. And more specifically, it's preferable to make the 
distance approximately 2.0 to 7.5 cm to detect a small amplitude P wave of 
ECG sufficiently. 
The insulating sheet 122 is provided so that a human body and the radiation 
plate 104b and the base plate 104a making up the antenna do not come in 
direct contact with each other. It may be made of any material if the 
material has an insulating property; the material is not limited. 
The adhesive 123 is provided for strongly fixing the living body placement 
section 101 to a living body; preferably it is a substance not giving an 
impetus to the living body. For example, a known adhesive material 
excellent in intimate contact with the living body placement section 101, 
such as double-sided adhesive tape, an acrylic family, a rubber family, a 
silicone family, or a vinyl ether family, can be used. 
The transmitter 106 is attached to the living body placement section 101 as 
described above, whereby the loop antenna parts 103a and 103b are 
connected, forming one loop antenna 103, and the base plate 104a and the 
radiation plate 104b are connected through the circuit on the board, 
forming the MSA 104. When the described biological signal transmission 
apparatus is placed on a living body surface as shown in FIG. 30, the 
living body placement section 101 is bonded to the surface of the living 
body of a subject via the adhesive 123 and the water-containing gels 121a 
and 121b are attached at a first intercostal space left sternal border on 
a left chest along a position 800b in such a manner that the 
water-containing gels 121a and 121b are positioned through midclavicular 
line and are parallel to a clavicle, as shown in FIG. 38. Thus, there is 
obtained biological signals 801b which is highly corrective to ECG 
detected in the method of standard limb lead (II). In addition, the stable 
ECG having high correction with ECG of standard limb lead (II) can be 
obtained as ling as the living body placement section is attached to area 
within the range of 2.5 cm apart from the 800b, or second intercostal 
space and it's not always needed to position water-containing gels 121a 
and 121b through midclavicular line. 
Upon the attachment, as shown in FIG. 39, the water-containing gels 121a 
and 121b are attached on a chest defined between a xiphoid process and a 
navel through and perpendicular to a midsternal line so as to obtain 
biological signals 801a which is highly correlative to ECG detected in the 
method of standard limb lead (II). 
In addition, the stable ECG having high correlation to ECG of standard limb 
lead (II) can be obtained as long as the living body placement section is 
attached to area within the range of 2.5 cm apart from the 800a, and it's 
not always needed to position water-containing gels 121a and 121b through 
midsternal line. 
Biological signals detected on the conductive terminals 121c and 121d are 
sent through the hooks 120a and 120b to the transmitter 106 and are 
processed by the electric circuitry 111 in the transmitter 106, then are 
sent through the hooks 116a and 116b to the loop antenna 103 and through 
the hook 118 to the MSA 104 from which the biological signals are 
transmitted to the receiver (not shown) by radio. 
According to the embodiment, the biological signals detected on the 
electrodes 105a and 105b are transmitted by radio through the loop antenna 
103 and the MSA 104 different in characteristics, so that the directivity 
can be improved, the radiation capability can be enhanced, and the radio 
wave band width can be enlarged. The loop antenna 103 and the MSA 104 are 
each divided into two parts, one of which is placed in the support 102 and 
the other in the transmitter 106. Thus, the transmitter 106 can be 
miniaturized as compared with the case where the whole antennas are 
installed in the transmitter 106. 
In the embodiment, the two electrodes 105 are used, but similar functions 
and advantages can be provided if one electrode 105 is used. Two loop 
antennas 103 each divided into two parts (103a and 103b and 103c and 103d) 
may be provided in place of the MSA 104, as shown in FIG. 19 and FIG. 20. 
In this case, the 103a and 103c are placed in a direction orthogonal to 
each other and the 103b and 103d are placed in a direction orthogonal to 
each other, whereby the directivity can be improved. In this case, the 
hooks 116a and 116c are connected to ends of the loop antenna parts 103b 
and 103c and the hooks 116d and 116b are connected to the transmission 
section 110 of the electric circuitry 111. Opposite ends of the loop 
antenna parts 103b and 103c are connected to the transmission section 110 
of the electric circuitry 111. 
Fifth Embodiment 
FIG. 21 to FIG. 24 show a configuration example of a fifth embodiment of 
the invention and FIG. 25 to FIG. 27 show a configuration example of a 
sixth embodiment of the invention. Parts identical with or similar to 
those previously described with reference to FIG. 14 to FIG. 16 are 
denoted by the same reference numerals in FIG. 21 to FIG. 27 and will not 
be discussed again in detail. 
FIG. 21 is a block diagram to show a configuration example of the fifth 
embodiment of the invention. FIG. 22 is an exploded perspective view to 
show a specific configuration example of a living body placement section 
in FIG. 21. FIG. 23 is an external perspective view of the living body 
placement section shown in FIG. 22 and a transmitter placed thereon. FIG. 
24 is a schematic representation to show placement of antennas when the 
transmitter in FIG. 23 is placed on the living body placement section. 
The embodiment is characterized by the fact that one antenna 603 of two 
antennas 603 and 604 is divided into two parts, that one antenna division 
part 603a, an electrode 105, and the whole antenna 604 are placed on a 
support 102, and that the other antenna division part 603b is placed in a 
transmitter 106, as shown in FIG. 21. In the embodiment, one electrode 105 
is used and a connector 151 placed on another part of a living body is 
connected to an amplification section 107 through a connector 152, but two 
or more electrodes 105 may be used. In the embodiment, the antennas 603 
and 604 are MSAs, one antenna 603 is divided into two parts, and only the 
radiation plate 603b of the divided antenna 603 is placed in the 
transmitter 106. 
In FIG. 22, a radiation plate 604b like a semi-disk is fixed to the upper 
face of the support 102 formed of a dielectric material like a disk and a 
base plate 153 like a disk is fixed to the lower face of the support 102 
concentrically. A caulking device 154 is inserted into the radiation plate 
604b of the MSA 604 from the lower face thereof and a hook 155 for the 
radiation plate is fixed to the upper end of the caulking device 154 
projecting from the radiation plate 604b by caulking. 
A caulking device 156 is inserted into the base plate 153 from the lower 
face thereof and passes through the support 102 and projects upward. A 
hook 118 for the ground plate is fixed to the projection end by the 
caulking. The electrode 105 is inserted into the center of the support 102 
from the lower face thereof and passes through the support 102 and 
projects upward. A hook 120 for deriving an electrocardiographic signal is 
fixed to the projection end by the caulking. Further, conductive 
water-containing gel 121 is attached to the lower end of the electrode 
105. 
The upper face of the support 102 is covered with a disk-like insulating 
sheet 157 and the hooks 118, 120, and 155 pass through the insulating 
sheet 157 and project upward. Likewise, the lower face of the support 102 
is covered with a disk-like insulating sheet 122 and the electrode 105 and 
the water-containing gel 121 pass through openings 153a and 122a made in 
the centers of the base plate 153 and the insulating sheet 122 and project 
downward. 
On the other hand, the radiation plate 603b is placed in the transmitter 
106. When the transmitter 106 is placed on the support 102 through the 
hooks 118, 120, and 155, the radiation plate 603b is opposed to the base 
plate 153 placed on the support 102, forming one MSA 603. Since the 
radiation plate 604b and the base plate 153 are opposed to each other on 
the support 102, another MSA 604 is formed on the support 102. The two 
MSAs 603 and 604 share the base plate 153, as shown in FIG. 24. 
According to the embodiment, functions and advantages almost similar to 
those of the fourth embodiment can be provided. In the fifth embodiment, 
one electrode 105 is installed in a living body placement section 101, but 
if two electrodes 105 are installed, they are placed in a similar manner 
to that shown in FIG. 15. 
Sixth Embodiment 
FIG. 25 is a block diagram to show a configuration example of the sixth 
embodiment of the invention. FIG. 26 is an exploded perspective view to 
show a specific configuration example of a living body placement section 
in FIG. 26. FIG. 27 is an external perspective view of the living body 
placement section shown in FIG. 26 and a transmitter placed thereon. 
The embodiment basically has almost the same configuration as the fifth 
embodiment except that an antenna 103 not divided into two parts is placed 
in a transmitter 106 as shown in FIG. 25 or that two electrodes 105 are 
provided. The number of the electrodes 105 may be one. 
In FIG. 26 and FIG. 27, the antenna 103 is a loop antenna, an antenna 104 
is an MSA, the loop antenna 103 is placed in the transmitter 106, and a 
base plate 104a and a radiation plate 104b of the MSA 104 are placed in a 
living body placement section 101 and the transmitter 106 respectively. 
The attachment structure of the base plate 104a, the electrodes 105, and 
an insulating plate 122 is similar to that in the fourth embodiment shown 
in FIG. 15. When the transmitter 106 is placed on the living body 
placement section 101, the base plate 104a and the radiation plate 104b 
are opposed to each other, forming the MSA 104. 
According to the embodiment, functions and advantages almost similar to 
those of the fourth embodiment can be provided. In the sixth embodiment, 
the number of the electrodes 105 is two, but if one electrode 105 is used, 
it is placed in a similar manner to that shown in FIG. 22. 
Seventh Embodiment 
A seventh embodiment of the invention will be discussed. FIG. 28 is a block 
diagram to show a configuration example of the seventh embodiment of the 
invention. FIG. 29 is an exploded perspective view. In the embodiment, two 
loop antennas 103A and 103B and an MSA 104 are attached to a transmitter 
106. 
As shown in FIG. 28, a living body placement section 101 comprises a pair 
of electrodes 105a and 105b integrally mounted on a support 102. The 
transmitter 5 contains electric circuitry 111 made up of an amplification 
section 107, a modulation section 108, a power supply section 109, and a 
transmission section 110. The loop antennas 103A and 103B and the MSA 104 
are electrically connected to the electric circuitry 111. The 
amplification section 107 and the electrodes 105 are connected 
electrically and mechanically through connectors 112. 
Power is supplied from the power supply section 109 to the amplification 
section 107, the modulation section 108, and the transmission section 110. 
When the support 102 is placed on the living body surface of a subject, 
biological signals detected on the electrodes 105a and 105b are amplified 
by the amplification section 107 and are modulated by the modulation 
section 108, then are sent from the transmission section 109 to the loop 
antennas 103A and 103B and the MSA 104. The biological signals are 
transmitted by radio from the antennas 103A, 103B, and 104 to a receiver 
(not shown). 
As shown in FIG. 29, a board 731 is housed in a cabinet 773 consisting of 
an upper lid 773a and a lower lid 773b. The two loop antennas 103A and 
103B are installed so that their loop opening faces are orthogonal to the 
board face of the board 731 and are orthogonal to each other. The two loop 
antennas 103A and 103B are placed in the proximity of the margins of the 
board 731 and are connected to the electric circuitry 111. 
The board 731 is provided with lands 732a and 732b for guiding biological 
signals detected from water-containing gels 718a and 718b and transferred 
through conductive terminals 718c and 718d, caulking devices 731a and 
731b, and convex hooks 719a and 719b into the electric circuitry 111. The 
board 731 is fixed to the lower lid 773b in parallel with the bottom face 
thereof by means of caulking devices 733a and 733b inserted into holes 
made in the centers of the lands 732a and 732b and holes made in 
projections of the inside of the lower lid 773b from above and concave 
hooks 734a and 734b corresponding to the caulking devices 733a and 733b. 
When the apparatus is placed on a living body, the bottom face of the 
lower lid 773b becomes almost parallel with the living body surface, so 
that the opening faces of the two loop antennas 103A and 103B become 
almost orthogonal to the living body surface. 
Further, the MSA 104 consisting of a radiation plate 104b and a base plate 
104a placed in parallel on a dielectric support member 735 is installed on 
the board 731. As described above, the board 731 is fixed to the lower lid 
773b in parallel with the bottom face thereof. Thus, when the apparatus is 
placed on a living body, the radiation plate 104b and the base plate 104a 
become almost parallel with the living body surface. At this time, the 
base plate 104a is nearer to the lower lid 773b side than the radiation 
plate 104b is, and thus is nearer to the living body surface than the 
radiation plate 104b is. 
A battery storage section is provided in the rear face of the board 731 and 
a battery 734 is stored in the battery storage section. 
The support 102 is formed of an insulating material like a plate and is 
narrow at the center. Projections of the caulking devices 731a and 731b 
are inserted into the holes made in ends of the conductive terminals 718c 
and 718d placed on the lower face of the support 102 and are fixed to the 
support 102 together with the conductive terminals 718c and 718d by means 
of the convex hooks 719a and 719b. The conductive water-containing gels 
718a and 718b are attached to the opposite ends of the conductive 
terminals 718c and 718d. Insulating sheets 720a and 720b are attached to 
the bottom faces of the caulking devices 731a and 731b for electrically 
insulating from a living body. 
The structures and materials of the members in the embodiment are almost 
similar to those of the corresponding members used with the 
above-described embodiments. 
According to the embodiment, the two loop antennas 103A and 103B, which are 
orthogonal to each other, are excellent in directivity, and since the 
opening faces of the loop antennas 103A and 103B are orthogonal to the 
living body surface, the sensitivity improves and the gain can be 
increased. In addition, all the antennas 103A, 103B, and 104 are contained 
in the transmitter, thus the living body placement section 101 can be 
removed from the transmitter 106 so that only the living body placement 
section 101 can be made disposable; costs for use can be reduced. 
FIG. 31(a) shows radio wave directivity of a loop antenna 1001 and a 
monopole antenna 1002, affected by a human body. As shown here, when the 
opening face of the loop antenna is placed at right angles to the surface 
of a human body, remarkably excellent directivity is provided as compared 
with the case where the monopole antenna is placed in roughly parallel 
with the surface of the human body. FIG. 31(b) is side view of the 
arrangement of the loop antenna and the monopole antenna attached with the 
human body along with FIG. 31(a). FIG. 32(a) is an illustration to show 
directivity provided when the opening face of one loop antenna 1001 is 
placed at right angles to the surface of a human body. FIG. 32(b) is side 
view of the arrangement of one loop antenna attached with the human body 
along with FIG. 32(a). FIG. 33(a) is an illustration to show directivity 
provided when the opening faces of two loop antennas 1001 are placed at 
right angles to the surface of a human body and are orthogonal to each 
other. FIG. 33(b) is side view of the arrangement of two loop antennas 
attached with the human body along with FIG. 33(a). As shown here, if two 
loop antennas 1001 are provided, they make a complement to each other in 
directivity and are less affected by the human body. 
According to the biological signal transmission apparatus of the present 
invention, when the apparatus is placed on a living body, it can be placed 
so that the loop opening face of the loop antenna becomes almost at right 
angles to the living body surface. Thus, the loop opening face can hold a 
constant direction relative to the living body surface and the human body, 
etc., does not block the opening face, so that attenuation of radio waves 
because of the effect of the human body can be lessened, the gain can be 
improved, and stable directivity can be provided. 
According to the biological signal transmission apparatus of another 
embodiment, when the apparatus is placed on a living body, the loop 
opening faces of the two loop antennas become almost at right angles to 
the living body surface and are placed in a direction almost perpendicular 
to each other. Thus, the loop antennas make a complement to each other in 
directivity and the gain can be improved. 
According to the biological signal transmission apparatus of a further 
embodiment, at least one loop antenna is contained in the transmitter, 
thus the person on whom the apparatus is placed is not restrained as 
compared with an antenna placed on the outside such as a monopole antenna 
(.lambda./4 antenna). The manufacturing cost of the support supporting the 
electrode and placed on the living body surface can be reduced and can be 
made disposable. 
According to the biological signal transmission apparatus of another 
embodiment, at least one of the loop antennas is divided into two parts, 
one loop antenna division part is placed in the support and the other is 
placed in the transmitter, and the transmitter is placed on the support, 
thereby putting the loop antenna division parts into one piece. Thus, the 
transmitter can be miniaturized or the loop opening face can be enlarged 
as compared with the case where all loop antennas are installed in the 
transmitter. Since the loop antenna is closely fixed in the proximity of a 
living body with the opening face orthogonal to the living body surface, 
the gain is also improved. 
According to the biological signal transmission apparatus of the present 
invention, the loop antenna for emitting a biological signal is integral 
with the support supporting the electrode, on which the transmitter is 
placed, and when the support is placed on the living body surface, the 
opening face of the loop antenna becomes almost at right angles to the 
living body surface, thus attenuation of radio waves of the loop antenna 
can be lessened and the gain can be improved. 
According to a further embodiment the biological signal transmission 
apparatus of the present invention, the loop antenna disposed so that the 
opening face is placed in a direction almost perpendicular to the living 
body surface, and the microstrip antenna having a radiation plate and a 
base plate opposed in parallel with the living body surface, the base 
plate being placed nearer to the living body surface, are placed, so that 
attenuation of radio waves because of the effect of the human body can be 
lessened and the two antennas make a complement to each other in 
directivity, thus the gain can be improved. 
According to another embodiment the biological signal transmission 
apparatus of the present invention, two loop antennas are disposed so that 
the opening faces are placed in a direction almost perpendicular to the 
living body surface and are almost at right angles to each other, and a 
microstrip antenna having a radiation plate and a base plate opposed in 
parallel with the living body surface, the base plate being placed nearer 
to the living body surface, are provided, so that the three antennas make 
a complement to each other in directivity and the gain can be improved. 
According to yet a further embodiment the biological signal transmission 
apparatus of the present invention, at least one of the loop antennas and 
the microstrip antenna is contained in the transmitter, so that the person 
on whom the apparatus is placed is not restrained as compared with a 
monopole antenna, etc., placed on the outside. Further, the manufacturing 
cost of the support supporting the electrode and placed on the living body 
surface can be reduced. 
According to another embodiment of the present invention, the loop antenna 
or the microstrip antenna can be placed on the support occupying a larger 
area than the transmitter, so that the loop opening area of the loop 
antenna can be enlarged and the areas of the radiation plate and the base 
plate of the microstrip antenna can be made large. Thus, the gain and band 
width can be improved. 
According to another embodiment of the present invention, the microstrip 
antenna having a radiation plate and a base plate opposed in parallel with 
the living body surface, the base plate being placed nearer to the living 
body surface, is provided, so that the microstrip antenna placed in 
parallel with the living body surface can be thinned and a large 
projection such as a monopole antenna is removed from the living body 
surface. Since the base plate is placed between the radiation plate and 
the living body surface, the antenna performance is less affected by the 
living body. 
According to another embodiment of the present invention, the microstrip 
antenna is contained in the transmitter, whereby the patient is not 
restrained as compared with an antenna placed on the outside such as a 
monopole antenna. Further, the manufacturing cost of the support 
supporting the electrode and placed on the living body surface can be 
reduced. 
According to yet a further embodiment of the present invention, the 
microstrip antenna is integral with the support and is connected to output 
of the electric circuitry through a connection member and the transmitter 
is placed on the support. Thus, the radiation plate and the base plate can 
be placed on the support occupying a larger area than the transmitter, so 
that they can be formed largely and the gain and band width can be 
improved. 
According to positioning of biological signal transmission apparatus of the 
present invention, ECG wave which is highly correlative to ECG detected in 
the method of standard limb lead (II) can be obtained by positioning two 
electrodes in the vicinity of first and second intercostal space left 
sternal border parallel to clavicle on a left chest or at area defined 
between a xiphoid process and a navel perpendicular to a midsternal line 
on a chest that help diagnosis of ECG wave easily.