KR20150113501A - Apparatus and method for measuring bio-impedance signal - Google Patents

Abstract

According to an embodiment of the present invention, disclosed is a device for measuring a bio-impedance signal which includes: an electrode unit which is attached to a certain part of a object, and includes a first electrode, a second electrode, a third electrode, and a fourth electrode; a current source for delivering a measurement current to the object using the first electrode, and the fourth electrode; a bio-impedance signal amplifying unit for outputting a bio-impedance signal of the object by amplifying the potential difference obtained using the second electrode, and the third electrode; a comparison unit for comparing a predetermined first level with a level of the bio-impedance signal outputted by the bio-impedance signal amplifying unit; and a control unit for controlling a level of the current to be measured based on a comparison result by the comparison unit.

Description

[0001] APPARATUS AND METHOD FOR MEASURING BIO-IMPEDANCE SIGNAL [0002]

The present invention relates to an apparatus and a method for measuring a bioimpedance signal of a subject. More particularly, the present invention relates to a bioimpedance signal measurement apparatus and method for measuring a bioimpedance signal of a target object by controlling a measurement current delivered to the target object.

U-Health, which combines IT and medical services to provide medical services such as prevention, diagnosis, and treatment of diseases at anytime and anywhere, has become an increasingly popular concern for the pursuit of high quality of life along with the worldwide well- It is getting bigger and bigger.

Utilizing the convergence of IT and medical technology, U-Health has created a platform for medical services in the daily life of home, school, office and so on, beyond the spatial limitation that medical service is done only in the hospital. In addition, through U-Health, the elderly, the disabled, and children will be able to regularly check their health status through various networks of wired and wireless in their daily life, and they will be able to maintain a high level of health through preventive measures. In addition, healthcare providers will be able to improve the quality of healthcare services by allowing them to review the status of their patients at any time.

A particularly important indicator in the medical field based on U-Health is the vital-sign, which represents the human metabolism. By constantly observing the vital sign, it is possible to identify the condition of the body, prevent various diseases in advance, and avoid the emergency situation.

In highly industrialized countries, cardiovascular disorders such as myocardial infarction, arteriosclerosis, and hypertension are common, which is one of the major causes of death. It is important to continuously measure the pulse wave velocity (PWV), which has a high correlation with cardiovascular disease, in order to prevent sudden death from such cardiovascular diseases.

As a method for measuring a pulse wave velocity of a subject, Patent No. 10-1056016 discloses a method of measuring a pulse wave transmission rate of a subject using a human electrocardiogram signal and a bio-impedance signal. However, the patent does not disclose the risk of the object due to the measuring current transmitted to the object in order to acquire the bioimpedance signal of the object.

In other words, while a typical user is expected to deliver a high intensity measurement current to a subject in order to measure the correct pulse wave velocity, a high intensity measurement current can be a danger to the subject. On the other hand, since it is difficult to measure an accurate pulse wave velocity using a measurement current having a very low intensity, it is necessary to appropriately adjust the intensity of a measurement current delivered to a target object.

An apparatus and method for measuring a bioimpedance signal according to an embodiment of the present invention aims at accurately obtaining a bioimpedance signal while preventing an object from being adversely affected by a measurement current.

In addition, an apparatus and method for measuring a bio-impedance signal according to an embodiment of the present invention aims at reducing power consumption of a current source that transmits a measurement current to a target object.

The apparatus for measuring bio-impedance signals according to an embodiment of the present invention includes:

An electrode unit including a first electrode, a second electrode, a third electrode, and a fourth electrode attached to a predetermined portion of the object; A current source for transmitting a measurement current to the object through the first electrode and the fourth electrode; A bio-impedance signal amplifying unit amplifying a potential difference obtained through the second electrode and the third electrode to output a bio-impedance signal of the target; A comparing unit comparing a magnitude of the bioimpedance signal outputted by the bioimpedance signal amplifying unit with a predetermined first magnitude; And a controller for adjusting the magnitude of the measurement current based on the comparison result by the comparison unit.

The controller may decrease the magnitude of the measurement current when the magnitude of the bioimpedance signal is larger than the first magnitude.

The controller may decrease the magnitude of the measurement current in units of a predetermined size.

Wherein the bioimpedance signal measurement apparatus further includes an envelope detection section that detects an envelope of the bioimpedance signal output by the bioimpedance signal amplification section, wherein the comparison section determines, based on the envelope detected by the envelope detection section, The magnitude of the bioimpedance signal can be determined.

The comparing unit may compare the magnitude of the bioimpedance signal with the first magnitude by a predetermined number of times during a predetermined time interval to determine whether the magnitude of the bioimpedance signal is greater than the first magnitude during the predetermined time interval .

Wherein the comparison unit obtains a result value indicating the comparison result of the magnitude of the bioimpedance signal and the first magnitude by the predetermined number of times and determines the magnitude of the bioimpedance signal of the bioimpedance signal based on the average value of the resultant value obtained by the predetermined number of times It can be determined whether the size is larger than the first size.

Wherein the comparing unit compares a magnitude of the bioimpedance signal output by the bioimpedance signal amplifying unit with a predetermined second magnitude, and when the magnitude of the bioimpedance signal is smaller than the second magnitude, The magnitude of the measurement current can be increased.

According to another embodiment of the present invention,

A keyboard pedestal for measuring a bio-impedance signal of a subject, comprising: a main body supporting an arm of the subject; An electrode unit including a first electrode, a second electrode, a third electrode, and a fourth electrode positioned on an upper surface of the main body to be attached to a predetermined portion of the arm; A current source for transmitting a measurement current to the arm through the first electrode and the fourth electrode; A bio-impedance signal amplifying unit amplifying a potential difference obtained through the second electrode and the third electrode to output a bio-impedance signal of the target; A comparing unit comparing a magnitude of the bioimpedance signal outputted by the bioimpedance signal amplifying unit with a predetermined first magnitude; And a controller for adjusting the magnitude of the measurement current based on the comparison result by the comparison unit.

According to another embodiment of the present invention, there is provided a method of measuring a bio-

A method for measuring a bioimpedance signal by a bioimpedance signal measurement apparatus, the method comprising the steps of: measuring a bioimpedance signal of a living body through a first electrode, a second electrode, a third electrode, Transmitting a measurement current to the object; Amplifying a potential difference obtained through the second electrode and the third electrode to output a bioimpedance signal of the subject; Comparing a magnitude of the bioimpedance signal with a predetermined first magnitude; And adjusting a magnitude of the measurement current based on the comparison result.

The apparatus and method for measuring a bioimpedance signal according to an embodiment of the present invention can precisely acquire a bioimpedance signal while preventing an object from being adversely affected by a measurement current.

In addition, the apparatus and method for measuring a bio-impedance signal according to an embodiment of the present invention can reduce power consumption of a current source that transmits a measurement current to a target object.

1 is a view for explaining the operation principle of a general bioimpedance signal measuring apparatus.
2 is a diagram showing a configuration of an apparatus for measuring a bioimpedance signal according to an embodiment of the present invention.
3 is a flowchart showing a procedure of a bioimpedance signal measurement method according to another embodiment of the present invention.
4 is a flowchart showing in detail the step S330 of FIG.
5 is a view showing a keyboard pedestal according to another embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

The term " part " used in this embodiment means a hardware component such as software, FPGA, or ASIC, and 'part' performs certain roles. However, 'minus' is not limited to software or hardware. The " part " may be configured to be in an addressable storage medium and configured to play back one or more processors. Thus, by way of example, and by no means, the terms " component " or " component " means any combination of components, such as software components, object- oriented software components, class components and task components, Subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays and variables. The functions provided in the components and parts may be combined into a smaller number of components and parts or further separated into additional components and parts.

1 is a view for explaining the operation principle of a general bioimpedance signal measuring apparatus. 1 is a diagram showing a part of a target object 1 modeled by an electric component. Particularly, the skin 2 and the blood vessel 3 of the arm portion of the object 1 are modeled.

The bioimpedance signal focuses on the fact that the impedance of the blood vessel 3 varies finely depending on the pulse wave in the blood vessel 3 and makes it possible to flow a minute current to a part of the subject 1, And is a signal generated by detecting the potential difference of the portion of the blood vessel 3 through which the current flows. That is, the bioimpedance signal means an electrical signal corresponding to a change in the impedance of the blood vessel 3 measured by the subject 1. Therefore, like the photorefractive blood flow measurement signal, a regular pole value synchronized with the peak value of the electrocardiogram signal, that is, the R peak value appears in the bioimpedance signal.

Referring to Fig. 1, a subject 1 includes a skin 2 and a blood vessel 3. A plurality of electrodes 32, 34, 36, and 38 for measuring a bioimpedance signal are attached to the surface of the skin 2 of the object 1. The skin 2 to which the plurality of electrodes 32, 34, 36 and 38 are attached can be modeled as a plurality of impedances Zs1, Zs2, Zs3 and Zs4 connected in parallel. The plurality of impedances Zs1, Zs2, Zs3 and Zs4 may comprise the contact impedance between the plurality of electrodes 32,34, 36,38 and the skin 2 and the impedance of the skin 2 itself.

The blood vessel 3 can be modeled by a serial connection of a constant impedance Zi irrespective of an impedance? Zi and a pulse wave depending on a pulse wave. Although the impedances Zs1, Zs2, Zs3, Zs4, Zi and Zi are shown in the form of resistors in FIG. 1, the impedances Zs1, Zs2, Zs3, Zs4, Zi, Can have both capacitance and inductance values.

A general bio-impedance signal measuring apparatus can generate a measuring current for measuring the bio-impedance signal of a target object in the current source 10. The measurement current passes through the impedances Zi and DELTA Zi included in the blood vessel 3 through the first electrode 32 and the fourth electrode 38. [ The second electrode (34) and the third electrode (36) can detect the potential difference generated by the measurement current and measure the bioimpedance signal through the measurement unit (20).

The plurality of impedances Zs1, Zs2, Zs3, and Zs4 included in the skin 2 may have the same impedance value or different impedance values. However, in a general bioimpedance signal measuring apparatus, the impedance value of a plurality of impedances (Zs1, Zs2, Zs3, Zs4) included in the skin 2 does not affect the measurement of the bioimpedance signal. This will be described later with reference to FIG.

2 is a diagram showing a configuration of an apparatus 100 for measuring a bioimpedance signal according to an embodiment of the present invention.

2, the bioimpedance signal measurement apparatus 100 includes a current source 110, an electrode unit 130, a bioimpedance signal amplification unit 150, a comparison unit 170, and a control unit 190. The bioimpedance signal measurement apparatus 100 may be implemented as an integrated microchip.

The bioimpedance signal measurement apparatus 100 may be connected to a portion 101 of the object through the electrode unit 130. 1, a portion 101 of the object may be a structure modeled by an electric component of skin and blood vessels of a subject, and may have a constant impedance Zi regardless of an impedance? Zi and a pulse wave, . ≪ / RTI >

The current source 110 generates a measurement current (it) that is transmitted to the portion 101 of the object. Current source 110 may include a local oscillator 112 and a voltage-to-current converter 114.

The local oscillator 112 is coupled to ground and can generate a local oscillation signal. The local oscillation signal may include an alternating voltage component having a constant frequency. In one embodiment, the local oscillation signal may have a frequency of about 10 kHz.

The voltage-to-current converter 114 may convert the local oscillation signal to the measurement current it. The voltage-to-current converter can generate a constant-magnitude alternating current having a constant frequency. In one embodiment, the measuring current, it, may have a frequency of about 10 kHz and have a magnitude of about 1 mA.

The electrode unit 130 transmits the measuring current it to the portion 101 of the object and detects the potential difference of the portion 101 of the object generated by the measuring current it transmitted to the portion 101. [ The electrode unit 130 may include a first electrode 132, a second electrode 134, a third electrode 136, and a fourth electrode 138.

The first electrode 132 and the fourth electrode 138 are connected to the current source 110 and can transmit the measurement current it to the portion 101 of the target object.

The second electrode 134 and the third electrode 136 can detect the potential difference of the portion 101 of the object generated based on the measurement current it.

The first electrode 132, the second electrode 134, the third electrode 136 and the fourth electrode 138 are fixed to the portion 101 of the object using an adhesive member such as a tape . In another embodiment, each of the first electrode 132, the second electrode 134, the third electrode 136, and the fourth electrode 138 may include an insulating sheet, a conductive sheet, and a tacky sheet.

In another embodiment, the bioimpedance signal measurement apparatus 100 may further include electrodes other than the first electrode 132, the second electrode 134, the third electrode 136, and the fourth electrode 138 . In this case, the bioimpedance signal measurement apparatus 100 can simultaneously measure the bioimpedance signal for various parts of the object, thereby shortening the measurement time and improving the accuracy of the measurement.

The bioimpedance signal amplifying unit 150 outputs the bioimpedance signal based on the potential difference of the portion 101 of the target object detected through the electrode unit 130. In one embodiment, the bio-impedance signal amplifier 150 may be implemented in the form of a differential amplifier. In this case, the bio-impedance signal amplifying unit 150 may be implemented in the form of an instrumentation amplifier or a general differential amplifier including one operational amplifier. Although not shown in FIG. 2, when the bio-impedance signal amplifier 150 is implemented in the form of a device amplifier, the bio-impedance signal amplifier 150 may include three operational amplifiers and a plurality of resistors. In this case, the bioimpedance signal amplifying unit 150 may have high input impedance and high common mode rejection ratio (CMRR) characteristics. Alternatively, the bioimpedance signal amplifying unit 150 can be implemented with only passive elements, and can be designed with low power, and a common mode rejection ratio (CMRR) can be improved through a chopping technique. Since the configuration of the device amplifier is disclosed in the prior art, a detailed description thereof will be omitted.

When the bioimpedance signal amplifying unit 150 is implemented in the form of a device amplifier, the input impedance of the bioimpedance signal amplifying unit 150 corresponds to the impedances (Zs1, Zs2, and Zs3 in Fig. 1) , Zs4). ≪ / RTI > In one embodiment, the input impedance of the bioimpedance signal amplifier 150 may have a value 20 times greater than the impedances (Zs1, Zs2, Zs3, and Zs4 in FIG. 2) included in the skin of the subject. Therefore, the influence of the impedances (Zs1, Zs2, Zs3, and Zs4 in Fig. 2) included in the skin of the subject in measuring the bioimpedance signal may be very small. As shown in Fig. 2, The impedances (Zs1, Zs2, Zs3, Zs4 in Fig. 2) included in the skin of the object can be omitted.

Although not shown in FIG. 2, the bio-impedance signal amplifier 150 may be connected to an envelope detector and a band-pass filter.

The envelope detection unit detects an envelope of the bioimpedance signal outputted by the bioimpedance signal amplification unit (150). When the measurement current is an alternating current having a constant frequency, the envelope detecting section can remove the alternating current component included in the bioimpedance signal. In one embodiment, the envelope detector may comprise a diode and a low-pass filter. The configuration of the envelope detector including the diode and the low-pass filter is disclosed in the prior art, and thus a detailed description thereof will be omitted.

The comparing unit 170 compares the magnitude of the bioimpedance signal outputted by the bioimpedance signal amplifying unit 150 or the magnitude of the envelope of the bioimpedance signal outputted by the envelope detecting unit described above with a predetermined first magnitude. The first size is the maximum value of the appropriate bioimpedance signal range, which can be arbitrarily set by the user.

Alternatively, the comparing unit 170 may compare the magnitude of the bioimpedance signal with the first magnitude by a predetermined number of times during a predetermined time interval, and determine whether the magnitude of the bioimpedance signal is greater than the first magnitude for a predetermined time interval . If the comparison unit 170 compares only the first magnitude of the bioimpedance signal at a certain point in time and the magnitude of the bioimpedance signal at that point in time is inaccurate due to noise or the like, And compares the magnitude of the bioimpedance signal with the first magnitude for a predetermined time interval.

Specifically, the comparator 170 obtains a result indicating a result of comparison between the magnitude of the bioimpedance signal and the first magnitude by a predetermined number of times, and calculates a magnitude of the bioimpedance signal based on the average value of the magnitude of the magnitude Is greater than the first size. For example, when the size of the bioimpedance signal is greater than the first size, the comparator 170 outputs 1 as a result value. When the size of the bioimpedance signal is smaller than the first size, can do. If the result values of 1, 0, 0, 1, and 1 are obtained, the comparing unit 170 compares the average value of the result values, that is, 3/5, with a predetermined reference value to determine whether the size of the bio- 1 size. When the predetermined reference value is set to 1/2, the comparing unit 170 may determine that the size of the bioimpedance signal is larger than the first size for a predetermined time interval.

Meanwhile, the comparison unit 170 may compare the size of the bioimpedance signal output by the bioimpedance signal amplification unit 150 or the size of the envelope of the bioimpedance signal output by the envelope detection unit with a predetermined second size . The second size is the minimum value of the appropriate bioimpedance signal range, which can also be arbitrarily set by the user.

The control unit 190 adjusts the magnitude of the measurement current based on the magnitude of the bioimpedance signal and the comparison result with respect to the first magnitude.

For example, when the size of the bioimpedance signal is larger than the first size, the controller 190 may decrease the magnitude of the measurement current. Since the magnitude of the bioimpedance signal is larger than the first magnitude, it means that the magnitude of the magnitude of the magnitude of the magnitude of the magnitude of the magnitude of the magnitude of the magnitude of the magnitude of the magnitude of the magnitude of the magnitude of the magnitude of the magnitude of the magnitude of the magnitude. The control unit 190 may reduce the magnitude of the measurement current by a predetermined unit of magnitude.

In addition, the controller 190 may adjust the measurement current based on the magnitude of the bioimpedance signal and the comparison result with respect to the second magnitude.

For example, when the size of the bioimpedance signal is smaller than the second size, the controller 190 may increase the size of the measurement current. The fact that the size of the bioimpedance signal is smaller than the second size means that the size of the measurement current delivered to the object is small, so that the controller 190 increases the size of the measurement current. The control unit 190 may increase the magnitude of the measurement current by a predetermined unit.

That is, the bioimpedance signal measurement apparatus 100 according to an embodiment of the present invention compares the size of the bioimpedance signal output by the bioimpedance signal amplification unit 150 with a predetermined first size or second size , It is possible to determine the magnitude of the measurement current that is safe for the object and can acquire the accurate bioimpedance signal. Accordingly, it is possible to prevent a measurement current of a large intensity from being applied to the object, and a large power consumption of the current source 110 can also be prevented.

3 is a flowchart showing a procedure of a bio-impedance signal measuring method according to an embodiment of the present invention. Referring to FIG. 3, the method for measuring a bio-impedance signal according to an embodiment of the present invention includes steps that are processed in a time-series manner in the bio-impedance signal measurement apparatus 100 shown in FIG. Accordingly, it is understood that the contents described above with respect to the bio-impedance signal measuring apparatus 100 shown in FIG. 2 are applied to the bio-impedance signal measuring method of FIG. 3, even if omitted from the following description.

In step S310, the bioimpedance signal measurement apparatus 100 measures a measurement current to a target object through a first electrode and a fourth electrode among a first electrode, a second electrode, a third electrode, and a fourth electrode attached to a predetermined portion of a target object . In one embodiment, the first electrode, the second electrode, the third electrode, and the fourth electrode may be fixed to a portion of the object using an adhesive member such as a tape. In another embodiment, each of the first electrode, the second electrode, the third electrode, and the fourth electrode may include an insulating sheet, a conductive sheet, and a tacky sheet.

In step S320, the bio-impedance signal measurement apparatus 100 amplifies the potential difference obtained through the second and third electrodes and outputs a bio-impedance signal of the target object. The bioimpedance signal measurement apparatus 100 may transmit the bioimpedance signal of the amplified object to the envelope detection unit.

In step S330, the bioimpedance signal measurement apparatus 100 compares the size of the bioimpedance signal with a predetermined first size. The first size may be arbitrarily set by the user.

In step S340, the bio-impedance signal measurement apparatus 100 adjusts the magnitude of the measurement current based on the comparison result. Specifically, when the size of the bioimpedance signal is larger than the first size, the bioimpedance signal measurement apparatus 100 can reduce the magnitude of the measurement current.

4 is a flowchart showing in detail the step S330 of FIG.

In step S410, the bioimpedance signal measurement apparatus 100 detects an envelope of the bioimpedance signal.

In step S420, the bioimpedance signal measurement apparatus 100 compares the size of the bioimpedance signal with the first size by a predetermined number of times during a predetermined time interval.

In step S430, the bio-impedance signal measurement apparatus 100 acquires a result value indicating a comparison result between the magnitude of the bio-impedance signal and the first magnitude by a predetermined number of times. The result value indicating the comparison result of the magnitude of the bioimpedance signal and the first magnitude may include 0 or 1.

In step S440, the bio-impedance signal measurement apparatus 100 determines whether the size of the bioimpedance signal is larger than the first size for a predetermined time interval based on the average value of the results obtained a predetermined number of times.

5 is a view showing a keyboard pedestal 500 according to another embodiment of the present invention. The bio-impedance signal measuring apparatus 100 according to an embodiment of the present invention may be implemented as the keyboard pedestal 500 shown in FIG.

The keyboard support 500 may include a body portion 505, a current source, an electrode portion 530, a bio-impedance signal amplification portion, a comparison portion, and a control portion. The current source, the bioimpedance signal amplifying unit, the comparing unit and the control unit may be implemented as a microchip integrated with the electrode unit 530, or may be located inside the main body unit 505.

The body portion 505 supports the arm of the object. The main body portion 505 is disposed on one side of the keyboard, and can support the arm of the target body when the target body desires to use the keyboard.

The electrode unit 530 includes a first electrode 532, a second electrode 534, a third electrode 536 and a fourth electrode 538 and includes a first electrode 532, a second electrode 534, The third electrode 536 and the fourth electrode 538 may be positioned on the upper surface of the main body 505 and attached to the arms of the target body.

The current source transmits the measurement current to the object through the first electrode 532 and the fourth electrode 538. The bioimpedance signal amplification unit amplifies the potential difference obtained through the second electrode 534 and the third electrode 536 And outputs a bioimpedance signal of the subject.

The comparison unit compares the size of the envelope of the bioimpedance signal output by the bioimpedance signal amplification unit or the bioimpedance signal output by the envelope detection unit with a predetermined first size.

The controller adjusts the magnitude of the measurement current based on the magnitude of the bioimpedance signal and the comparison result with respect to the first magnitude. For example, if the size of the bioimpedance signal is larger than the first size, the controller can reduce the magnitude of the measurement current. The controller may reduce the magnitude of the measurement current by a predetermined unit of magnitude.

According to the keyboard pedestal 500 according to another embodiment of the present invention, even if the object supports the arm on the keyboard pedestal 500 in order to use the keyboard, Can be automatically measured.

The above-described embodiments of the present invention can be embodied in a general-purpose digital computer that can be embodied as a program that can be executed by a computer and operates the program using a computer-readable recording medium.

The computer readable recording medium may be a magnetic storage medium such as a ROM, a floppy disk, a hard disk, etc., an optical reading medium such as a CD-ROM or a DVD and a carrier wave such as the Internet Lt; / RTI > transmission).

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

100: bioimpedance signal measuring device
110: current source
130:
150: Biometric Impedance Signal Amplification Unit
170:
190:
500: keyboard stand
505:
530:

Claims (9)

An electrode unit including a first electrode, a second electrode, a third electrode, and a fourth electrode attached to a predetermined portion of the object;
A current source for transmitting a measurement current to the object through the first electrode and the fourth electrode;
A bio-impedance signal amplifying unit amplifying a potential difference obtained through the second electrode and the third electrode to output a bio-impedance signal of the target;
A comparing unit comparing a magnitude of the bioimpedance signal outputted by the bioimpedance signal amplifying unit with a predetermined first magnitude; And
And a controller for adjusting the magnitude of the measurement current based on the comparison result by the comparison unit.
The method according to claim 1,
Wherein,
And decreases the magnitude of the measurement current when the magnitude of the bioimpedance signal is greater than the first magnitude.
3. The method of claim 2,
Wherein,
Wherein the measurement current is reduced in units of a predetermined size.
The method according to claim 1,
Wherein the bioimpedance signal measurement device comprises:
Further comprising an envelope detector for detecting an envelope of the bioimpedance signal output by the bioimpedance signal amplifier,
Wherein,
And the size of the bioimpedance signal is determined based on the envelope detected by the envelope detector.
5. The method of claim 4,
Wherein,
Wherein the bioimpedance signal generation unit compares the magnitude of the bioimpedance signal with the first magnitude at a predetermined number of times during a predetermined time interval to determine whether the magnitude of the bioimpedance signal is greater than the first magnitude during the predetermined time interval Signal measuring device.
6. The method of claim 5,
Wherein,
Wherein the bioimpedance signal is obtained by a predetermined number of times, and a result value indicating a result of comparison between the magnitude of the bioimpedance signal and the first magnitude is obtained by the predetermined number of times, 1 < / RTI > size of the bioimpedance signal.
The method according to claim 1,
Wherein,
And comparing the size of the bioimpedance signal outputted by the bioimpedance signal amplifying unit with a predetermined second size,
Wherein,
And increases the magnitude of the measurement current when the magnitude of the bioimpedance signal is smaller than the second magnitude.
A keyboard pedestal for measuring a bio-impedance signal of a subject,
A main body supporting an arm of the target object;
An electrode unit including a first electrode, a second electrode, a third electrode, and a fourth electrode positioned on an upper surface of the main body to be attached to a predetermined portion of the arm;
A current source for transmitting a measurement current to the arm through the first electrode and the fourth electrode;
A bio-impedance signal amplifying unit amplifying a potential difference obtained through the second electrode and the third electrode to output a bio-impedance signal of the target;
A comparing unit comparing a magnitude of the bioimpedance signal outputted by the bioimpedance signal amplifying unit with a predetermined first magnitude; And
And a controller for controlling the magnitude of the measurement current based on the comparison result by the comparison unit.
A method of measuring a bioimpedance signal by a bioimpedance signal measurement apparatus,
Transmitting a measurement current to the target object through the first electrode and the fourth electrode among a first electrode, a second electrode, a third electrode, and a fourth electrode attached to a predetermined portion of a target object;
Amplifying a potential difference obtained through the second electrode and the third electrode to output a bioimpedance signal of the subject;
Comparing a magnitude of the bioimpedance signal with a predetermined first magnitude; And
And adjusting a magnitude of the measurement current based on the comparison result.

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