JP2001321353A - Electric characteristic measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric characteristic measuring device suitable for a long-time monitoring or the measurement of bioelectric impedance of an infant. SOLUTION: A filter 7a filters the bioelectric impedance Xn to extract a steady component Xn0. The filter 7a extracts a component having a frequency, for example, less than 0.1 Hz (f0). A filter 7b filters the bioelectric impedance to extract a heart beat component Xn1. The filter 7b extracts a component having a frequency, for example, of 0.5 Hz (f1) or more and 4.0 Hz (f2) or less. A filter 7c filters the bioelectric impedance to extract a respiration component Xn2. The filter 7c extracts a component having a frequency, for example, of 0.1 Hz (f0) or more and less than 0.5 Hz (f1).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrical characteristic measuring apparatus capable of determining a subject's respiratory rate, heart rate, exercise rate and energy metabolism based on a bioelectrical impedance method.

[0002]

2. Description of the Related Art The inventor of the present invention has previously applied for an apparatus using an M-sequence signal as a bioelectrical impedance measuring apparatus (Japanese Patent Laid-Open No. 10-14898). In the invention, by performing a Fourier transform on the four-terminal A / D-converted signal, bioelectric impedance at many frequencies is measured to calculate information on the water content inside and outside the cell. Although not described in the specification, this apparatus outputs an M-sequence signal many times and performs synchronous addition of each signal in order to improve the SN ratio of the signal.

[0003] The prior art will be described below. 2. Description of the Related Art In recent years, research on the electrical characteristics of living organisms has been conducted for the purpose of evaluating the body composition of humans and animals. The electrical properties of living organisms vary significantly depending on the type of tissue or organ, for example,
In the case of humans, the electrical resistivity of blood is around 150 Ω · cm, whereas the electrical resistivity of bone and fat is 1 to 5 kΩ · cm.
cm. The electrical characteristics of the living body are called bioelectric impedance, and are measured by passing a small current between a plurality of electrodes attached to the body surface of the living body. The method of estimating the body water distribution, body fat percentage, and body fat mass of the subject from the bioelectric impedance obtained in this way is called the bioelectric impedance method ("Bioelectric impedance method as an evaluation method of body composition", Baumgartner , RN, etc.
Authors, "Bioelectric Impedance and Its Clinical Application", Medical Electronics and Biotechnology, Hiroshi Kanai, 20 (3) Jun 1982, "Estimation of Body Water Distribution by Impedance Method and Its Application",
Medical electronics and biotechnology, Makoto Haeno, 23 (6) 1985, "Long-term measurement of urinary bladder volume by impedance method", Ergonomics, Yasuo Kuchimachi, 28 (3) 1992, etc.) .

[0004] Bioelectric impedance is derived from the resistance of a living body to the current carried by ions in the body (resistance) and the reactance associated with various types of polarization processes created by cell membranes, tissue interfaces, or non-ionized tissue. Be composed. Capacitance, which is the reciprocal of reactance, causes a time delay in current rather than voltage, and creates a phase shift (phase shift). This value is the arctangent of the ratio of reactance to resistance (arctangent). It can be determined geometrically as a phase angle.

The bioelectric impedance Z, the resistance R, the reactance X and the electric phase angle φ depend on the frequency. At very low frequencies f _L , the bioelectrical impedance Z at the cell membrane-tissue interface is too high to conduct electricity. Thus, electricity flows only through the extracellular fluid and the measured bioelectrical impedance Z is purely a resistance R.

Next, as the frequency increases, the current penetrates the cell membrane, the reactance X increases, and the phase angle φ increases. The magnitude of the bioelectrical impedance Z is equal to the value of the vector defined by Z ² = R ² + X ² . The frequency at which both the reactance X and the phase angle φ are maximized is called a critical frequency f _C , which is one electrical characteristic value of a living body that is a conductive conductor. Beyond this critical frequency f _C , the cell membrane-tissue interface loses its capacitive capacity, and the reactance X decreases accordingly. At very high frequencies f _H , the bioelectrical impedance Z is again purely equivalent to the resistance R.

FIG. 5 is an electrical equivalent circuit diagram (equivalent circuit model) of the human body. In this figure, Cmk represents the cell membrane capacity, and Rik and Re represent the intracellular fluid resistance and the extracellular fluid resistance, respectively. At low frequencies f _L , the current is mainly flowing in the extracellular space, and the impedance Z is equal to the extracellular fluid resistance Re. At high frequencies f _H , the current passes through the cell membrane completely, and the cell membrane capacitance Cmk is substantially equivalent to being short-circuited. Accordingly, the impedance at high frequency f _H Z
Is the combined resistance Ri · Re / (Ri + Re), (1 / Ri
= Σ1 / Rik).

According to the method described above, the intracellular fluid resistance R
i and the extracellular fluid resistance Re can be determined, and based on these, the lean body mass of the subject can be estimated, and a change in body water distribution can be estimated based on a change in these resistances Re and Ri. As a bioelectrical impedance measuring device that performs measurement / estimation of each of these parameters by injecting a small sine wave current of a plurality of frequencies arbitrarily selected into a living body and digitally processing the obtained signal, there is a special table. 6-5
The thing described in 06854 is known.

In such a bioelectrical impedance measuring apparatus, it is known to measure the influence of the bioelectrical impedance measured by the subject's respiration or heartbeat because the bioelectrical impedance changes. For example, Tokuhyo Hei 8-5024
No. 30 discloses that, in order to measure the influence of respiration, the impedance change between a state in which breathing is stopped and a normal state of respiration is measured, and in order to measure the effect of heartbeat, the breathing is stopped. It describes measuring the peak-to-peak amplitude of the variable impedance signal in the closed state.

[0010]

However, the above-described measurement method for stopping breathing has a problem that it is not suitable for long-term monitoring or measurement of children. Conversely, there has been no idea to measure the state of respiration or heartbeat by utilizing the fact that bioelectric impedance measurement is affected by respiration or heartbeat. The present invention has been made in view of such a point, and an object of the present invention is to provide an electrical characteristic measuring device that is suitable for a long-term monitor and a measurement in a case of a child with respect to the state of respiration and heartbeat.

[0011]

According to the present invention, there is provided an electric characteristic measuring apparatus comprising: signal generating means for generating a measuring signal; and current measuring means for measuring a current flowing when the generated measuring signal is applied to a subject's body. A voltage measuring means for measuring a potential difference generated between predetermined surface portions of the subject's body, and a bioelectric impedance from a current value measured by the current measuring means and a voltage value measured by the voltage measuring means. A calculating means for calculating, and a heartbeat component extracting filter for extracting a heartbeat component from the bioelectrical impedance calculated by the calculating means.

The calculating means can calculate the heart rate of the subject by calculating the heart rate from the heart rate component extracted by the heart rate component extracting filter. The heartbeat component extraction filter can accurately extract a heartbeat component from bioelectric impedance by extracting a signal having a frequency of 0.5 to 4.0 Hz.

[0013] The electrical characteristic measuring apparatus of the present invention comprises: signal generating means for generating a measurement signal; current measuring means for measuring a current flowing when the generated measurement signal is applied to the body of the subject; Voltage measuring means for measuring a potential difference generated between predetermined surface portions, and calculating means for calculating bioelectric impedance from a current value measured by the current measuring means and a voltage value measured by the voltage measuring means, A respiratory component extraction filter for extracting a respiratory component from the bioelectrical impedance calculated by the calculating means.

The calculating means calculates the respiratory volume from the respiratory component extracted by the respiratory component extracting filter, so that the respiratory volume of the subject can be measured. The respiratory component extraction filter can accurately extract a respiratory component from bioelectric impedance by extracting a signal having a frequency of 0.1 to 0.5 Hz.

The calculating means calculates the amount of exercise or energy metabolism of the subject by calculating the amount of exercise or energy metabolism from the calculated heart rate and respiratory rate. The calculating means calculates the amount of exercise or energy metabolism as a linear combination of the heart rate and the amount of respiration, and thereby can accurately obtain the amount of exercise or energy metabolism by simple calculation.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. The case where the present invention is used for a bioelectrical impedance measuring device will be described in detail. FIG. 1 is a block diagram showing an electrical configuration of the measuring device. As shown in FIG. 1, a bioelectrical impedance measuring device of this example includes a keyboard 1 and a body B of a subject.
The probe current Ia is sent out as a measurement signal to thereby control the measurement processing unit 2 for digitally processing the voltage / current information obtained from the subject's body B, and each unit of the apparatus. CPU (Central Processing Unit) 3 for calculating quantities such as respiratory volume and heart rate from bioelectrical impedance of the human body based on the CPU 3
Display unit 4 for displaying the bioelectric impedance, respiratory volume, heart rate, and the like of body B of the subject calculated by
ROM 6, which stores a processing program of CPU 3,
A RAM 5 in which a data area for temporarily storing various data (for example, the height, weight, and sex of the subject, amounts of extracellular fluid and intracellular fluid, etc.) and a work area of the CPU 3 are set;
And a digital filter 7 for separating each of a constant component, a respiratory component, and a heartbeat component according to the frequency component of the bioelectric impedance calculated by the above.

The keyboard 1 is used by a measurer to input a measurement start switch for instructing a start of measurement, a human body characteristic item such as height, weight, gender and age of a subject, and to measure a total measurement time T and a measurement interval t. The operation data of each key supplied from the keyboard 1 is converted into a key code by a key code generation circuit (not shown), and
Supplied to

The measurement processing section 2 is attached to a PIO (parallel interface) 71, a measurement signal generator 72, a low-pass filter (hereinafter referred to as LPF) 73, a coupling capacitor 74, and a predetermined part of the body. An output processing circuit including a surface electrode Hc; and surface electrodes Hp, Lp, and L that are also attached to a predetermined part of the body.
c, coupling capacitors 80a, 80b, 90, differential amplifier 81, I / V converter (current / voltage converter) 9
1. L composed of an analog anti-aliasing filter
PFs 82 and 92, an A / D converter 83.93, and an input processing circuit including sampling memories (ring buffers) 84 and 94.

In the measurement processing section 2, the measurement signal generator 7
2 is equal to or more than 10 kΩ over the entire signal frequency range in which the output resistance is generated, and every time a signal generation instruction signal is supplied from the CPU 3 via the PIO 71 at a predetermined cycle t during the entire measurement time T, The longest linear code (maximal li
LPF7 that repeatedly generates the probe current Ia of the (near codes) series (M series) a predetermined number of times and uses the generated probe current Ia as a measurement signal to remove high-frequency noise.
3 and a coupling capacitor 74 that removes the DC component from flowing to the subject's body B so as not to flow to the surface electrode Hc. The value of the probe current Ia is, for example, 500 to
800 μA. The supply period of the signal generation instruction signal is set to a measurement interval t set by the measurer using the keyboard 1.
Matches. Further, in this example, the number of repetitions of the probe current (measurement signal) Ia is 1 to 256 per signal generation instruction signal. The number of repetitions may be arbitrarily set by the measurer using the keyboard 1.
The number of repetitions increases as the number of repetitions increases. However, although it is a minute current, it may adversely affect the human body when continuously applied to the human body for a long time. Therefore, the number of repetitions is preferably 1 to 256.

Here, the M-sequence signal will be described. The M-sequence signal is a code signal generally used in a spread-spectrum communication system or a spread-spectrum ranging system, and is the longest code sequence generated by a shift register or a delay element having a certain length. Say. A binary M-sequence generator that generates an M-sequence signal having a length of (2 ⁿ -1) bits (n is a positive integer) is composed of an n-stage shift register and a logical combination of the n-stage states. And a logic circuit (exclusive logic circuit) that feeds back to the input of the shift register. M at a certain sample time (clock time)
The output of the sequence generator and the state of each stage is a function of the output of the feedback stage at the immediately preceding sample time. In this embodiment, an M-sequence generator having eight stages (n = 8) of shift registers is used. Further, the frequency of the shift clock of the shift register is set to 2 MHz.

When an impulse signal is used, energy concentrates in a small time interval (0.1 μsec), whereas a probe current using an M-sequence signal contains many frequency components, Since the energy is dispersed to about 1 msec, it does not damage the living body, and occurs at a time interval sufficiently shorter than the pulse or respiratory cycle. Absent. Furthermore, for example, in the case of a rectangular wave signal with a duty of 50%, the amplitude of the frequency spectrum is large at low frequencies,
Since the frequency characteristic of the SN ratio deteriorates in the high frequency region because it is small at high frequencies, the M-sequence signal has a substantially flat frequency characteristic of the SN ratio because the amplitude of the frequency spectrum is substantially flat over the entire frequency region. is there. Note that M
For details of the sequence signal, see “Spread Spectrum Communication System” by RCDixon (p.56 to p.89).

FIG. 2 is a diagram schematically showing a state of use of the electric impedance measuring device of the present embodiment. FIG.
In the method, the surface electrode Hc (first electrode) is electrically conductively adhered to the side of the subject's right breast at the time of measurement, and the surface electrode Lc (second electrode) is placed on the left breast across the breast. Adhered to the side conductively by the adhesive method. Therefore, the measurement signal (probe current) Ia enters the body B from the right chest portion of the subject.

The surface electrode Hp (third electrode) is conductively attached to the inside of the first electrode Hc next to the right breast of the subject by an adhesive method, and the surface electrode Lp (fourth electrode) is
It is conductively attached to the inside of the second electrode Lc on the left side of the chest across the chest by an adhesive method. Each of the above surface electrodes Hp, L
p, Hc, and Lc are measurement cables 10c, 10d, and 1
Oa and 10b are connected to the bioelectrical impedance measuring device 100.

FIG. 3 is a diagram illustrating a digital filter 7 used in an embodiment of the present invention. Filter 7a ~
7c extracts a constant component, a heartbeat component, and a respiratory component of the bioelectric impedance output from the CPU 3, respectively. Since the bioelectric impedance is disturbed by the respiratory component and the heartbeat component and changes every moment, by separating the respiratory component and the heartbeat component into only the constant component, there is no change, that is, the respiratory component and the heartbeat component are affected. The bioelectrical impedance in a state where the measurement is not performed can be obtained. Furthermore, the respiratory volume and the heart rate can be obtained from the respiratory component and the heart rate component.

The filter 7a provides impedance data at the bioelectric impedance Xn (measurement time nT (T is time unit), ie, n-th impedance data (Ro, impedance at 50 kHz of the measurement signal frequency, and measurement signal frequency of 50 kHz, respectively). A constant component Xn0 is extracted by filtering a temporal variation of the impedance of f _C ))). The filter 7a extracts, for example, a component having a frequency lower than 0.1 Hz (f0). The extracted constant component is output to the CPU 3 in order to determine the amount of body fat, the amount of water in the body, and the like.

The filter 7b filters the temporal variation of the bioelectrical impedance Xn to filter the heartbeat component Xn.
1 is extracted. The filter 7b has, for example, a frequency of 0.
A component between 5 Hz (f1) and 4.0 Hz (f2) is extracted. The heartbeat component thus extracted is output to the CPU 3 in order to obtain a heart rate, an amount of exercise, an amount of energy metabolism, and the like.

The filter 7c filters the temporal variation of the bioelectrical impedance Xn to filter the respiratory component Xn.
2 is extracted. The filter 7c has, for example, a frequency of 0.
A component of not less than 1 Hz (f0) and less than 0.5 Hz (f1) is extracted. The respiratory component extracted in this way is output to the CPU 3 in order to determine the respiratory volume, the amount of exercise, the amount of energy metabolism, and the like.

The filters 7a to 7c may be digital filters or analog filters. Filter 7a
If an analog filter is used for 7 to 7c, the CPU 3
After the output from is converted to an analog signal, filtering is performed.

FIG. 4 is a diagram showing C used in one embodiment of the present invention.
FIG. 3 is a diagram illustrating a function of processing an output of a digital filter 7 in a PU 3. The CPU 3 calculates a body fat mass from the constant component extracted by the filter 7a and calculates a body fat mass from the heartbeat component extracted by the filter 7b. Respiratory volume calculating unit 53 for obtaining a respiratory volume from the obtained respiratory component
And an exercise / energy metabolism calculating unit 54 for obtaining an exercise or energy metabolism from the obtained heart rate and respiration.
It is mainly composed of The obtained body fat amount, heart rate, respiratory amount, exercise amount, and energy metabolism are stored in the RAM 5 and displayed on the display unit 4.

Next, the measurement signal processing will be described. FIG.
As shown in the figure, the surface electrode (high-potential output terminal) Hp and the surface electrode Hc are conductively affixed to the side of the right breast of the subject by an adhesive method, while the surface electrode Lp and the surface electrode Lc are connected to the left. Adhered conductively to the side of the chest by the adhesive method.

The differential amplifier 81 shown in FIG. 1 detects a potential (potential difference) between two surface electrodes Hp and Lp sandwiching the chest. That is, the differential amplifier 81 has the probe current I
When a is applied to the subject's body B, the voltage Vp between the subject's chests is detected and input to the LPF 82. This voltage Vp is a voltage drop between the surface electrode Hp and the surface electrode Lp due to the bioelectric impedance of the body B of the subject.

The LPF 82 removes high frequency noise from the voltage Vp and supplies it to the A / D converter 83. LPF
The cutoff frequency 82 is lower than half the sampling frequency of the A / D converter 83. Thereby, aliasing noise generated in the A / D conversion processing by the A / D converter 83 is removed. The A / D converter 83 converts the noise-removed voltage Vp into a digital signal at a predetermined sampling cycle every time the digital conversion signal Sd is supplied from the CPU 3, and converts the digitized voltage Vp to the sampling cycle. The data is supplied to the sampling memory 84 every time.

The I / V converter 91 has two surface electrodes H
The current flowing between c and Lc is detected and converted into a voltage. That is, when the probe current Ia is applied to the subject's body B, the I / V converter 91 detects the probe current Ia flowing between the subject's chests, converts the probe current Ia to the voltage Vc, and then converts the LPF into the voltage Vc.
92.

The LPF 92 removes high-frequency noise from the input voltage Vc and supplies it to the A / D converter 93.
The cutoff frequency of the LPF 92 is lower than half the sampling frequency of the A / D converter 93. In this case, A /
The aliasing noise generated in the A / D conversion processing by the D converter 93 is removed. The A / D converter 93 converts the noise-removed voltage Vc into a digital signal at a predetermined sampling cycle every time the digital conversion signal Sd is supplied from the CPU 3, and converts the digitized voltage Vc into a sampling cycle. The data is supplied to the sampling memory 94 every time.

The CPU 3 starts the measurement by the above-described measurement processing unit 2 according to the processing program stored in the ROM 6, and detects the detection voltages Vp and V at a predetermined sampling cycle.
After sampling c for a predetermined number of times, the following processing is performed in addition to the control for stopping the measurement. That is, the CPU 3
First, the voltages Vp and Vc, which are functions of time, stored in the sampling memories 84 and 94 are sequentially read out, and the voltages Vp (f) and Vc (f) (f Is converted to a frequency), and averaging is performed to calculate bioelectric impedance Z (f) {= Vp (f) / Vc (f)} for each frequency.

Next, based on the obtained bioelectrical impedance Z (f) for each frequency, the CPU 3 obtains an impedance locus D as shown in FIG. From the obtained impedance locus D, the bioelectric impedance R0 of the body B of the subject at a frequency of 0 and the bioelectric impedance R at a frequency of infinity are obtained.
∞ is calculated, and from the calculation result, the intracellular fluid resistance and the extracellular fluid resistance of the body B of the subject are calculated.

In an actual human body tissue, cells of various sizes are arranged irregularly. Therefore, an electrical equivalent circuit close to the actual one has a series of a capacitance and a resistance having a time constant τ = Cmk · Rik. It is represented by a distributed constant circuit in which the connection elements are distributed (FIG. 6: Re is the extracellular fluid resistance, Rik is the intracellular fluid resistance of each cell, and Cmk is the cell membrane capacity of each cell). Therefore, the impedance locus D of the human body is an arc whose center is higher than the real axis as shown in FIG.

Next, based on the calculated intracellular fluid resistance Ri and extracellular fluid resistance Re, and the human body characteristic data such as the height, weight, sex and age of the subject inputted from the keyboard 1, a processing program is performed in advance. The body fat percentage, fat weight, lean body mass, intracellular fluid volume, extracellular fluid volume, and the sum of these body water ( Volume).
Then, the calculated data is displayed on the display unit 4.

Next, the CPU 3 determines whether or not the total measurement time T has elapsed. If it is determined that the total measurement time T has elapsed, the CPU 3 terminates the subsequent measurement processing. After waiting for the time t corresponding to to elapse, the same measurement processing is started again. Then, the above process is repeated until the entire measurement time T has elapsed.

On the other hand, the obtained bioelectric impedance is output from the CPU 3 to the filters 7a to 7c. The filter 7a extracts a constant component from bioelectric impedance. The filter 7b extracts a heartbeat component from the bioelectrical impedance. The filter 7c extracts a respiratory component from the bioelectrical impedance.

The extracted constant component is used by the body fat mass calculating section 51 of the CPU 3 to calculate the body fat mass, the body water mass and the like. Since this constant component does not include a heartbeat component or a respiratory component, when this constant component is obtained, a bioelectric impedance that is not affected by the heartbeat component or the respiratory component can be obtained, and is not affected by the heartbeat component or the respiratory component. Can obtain the body fat amount, the body water amount and the like.

From the extracted heart rate component, the heart rate is obtained by the heart rate calculator 52 of the CPU 3. There is no particular limitation on the method of calculating the heart rate from the heart rate component. An appropriate coefficient may be multiplied, or a correspondence table between the heart rate component and the heart rate may be prepared, and the heart rate corresponding to the heart rate component may be calculated. Can be used.

Also, the CPU 3
The respiratory volume calculation unit 53 calculates the respiratory volume. The method for calculating the respiratory volume from the respiratory component is similar to the method for calculating the heart rate from the heartbeat component, and is not particularly limited.

The heart rate and the respiratory rate obtained in this way are stored in the RAM 5, used as needed, and output to the display unit 4. The heart rate and the respiratory rate are used by the exercise amount / energy metabolism calculation unit 54 to calculate the exercise amount and the energy metabolism. Here, as a method of calculating the amount of exercise and the amount of energy metabolism using the heart rate and the respiratory rate, a linear combination aX +
There is a method of obtaining by bY (X: heart rate, Y: respiratory rate). The amount of exercise and energy metabolism obtained in this way are stored in the RAM 16, used as needed, and output to the display unit 4.

As described above, in the bioelectrical impedance measuring apparatus, which is the electric characteristic measuring apparatus according to the present embodiment, it is possible to obtain a bioelectrical impedance that is not affected by a heartbeat component and a respiratory component, and to obtain a bioelectrical impedance that is not affected by a heartbeat component and a respiratory component. It is possible to obtain the amount of body fat and the amount of water in the body without being affected.
As a result, long-term monitoring can be performed. In the bioelectrical impedance measuring device, which is the electrical characteristic measuring device according to the present embodiment, the heart rate and the respiratory rate can be obtained from the extracted heart rate component and the respiratory component.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and the design can be changed within the scope of the present invention. Even if there is, it is included in the present invention.

[0047]

As described above, the electrical characteristic measuring apparatus of the present invention can obtain a bioelectrical impedance which is not affected by a heartbeat component or a respiratory component, and can be obtained without being affected by a heartbeat component or a respiratory component. The body fat amount, the body water amount, etc. can be obtained. As a result, it is possible to monitor for a long time and measure the bioelectric impedance of a child. In the bioelectrical impedance measuring device, which is the electrical characteristic measuring device according to the present embodiment, the heart rate and the respiratory rate can be obtained from the extracted heart rate component and the respiratory component.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of an electrical impedance measuring device according to an embodiment of the present invention.

FIG. 2 is a diagram schematically showing a state of use of the electrical impedance measuring device of the present embodiment.

FIG. 3 is a diagram illustrating a digital filter used in an embodiment of the present invention.

FIG. 4 is a diagram illustrating a function of processing output of a digital filter in a CPU used in an embodiment of the present invention.

FIG. 5 is a diagram illustrating an impedance locus of a human body.

FIG. 6 is an electrical equivalent circuit diagram showing cells in a tissue of a human body.

[Explanation of symbols]

Reference Signs List 1 keyboard 3 CPU (computing means) 4 display unit 5 RAM 6 ROM 7 digital filter 10 measurement cable 51 body fat mass calculation unit 52 heart rate calculation unit 53 respiration volume calculation unit 54 exercise / energy metabolism calculation unit 72 measurement signal generation (Part of signal generating means) 73 LPF (part of signal generating means) 81 Differential amplifier (part of voltage measuring means) 82 LPF (part of voltage measuring means) 84, 94 Sampling memory 91 I / V Transducer (part of current measuring means) 92 LPF (part of current measuring means) 100 Bioelectric impedance measuring device (electrical property measuring device) Hc surface electrode Lc surface electrode Hp surface electrode Lp surface electrode

Claims (8)

[Claims] 1. A signal generation means for generating a measurement signal; a current measurement means for measuring a current flowing when the generated measurement signal is applied to a body of a subject; Voltage measuring means for measuring a potential difference to be measured; calculating means for calculating bioelectric impedance from a current value measured by the current measuring means and a voltage value measured by the voltage measuring means; An electrical characteristic measuring device, comprising: a heartbeat component extraction filter for extracting a heartbeat component from bioelectric impedance. 2. The electrical characteristic measuring apparatus according to claim 1, wherein said calculating means calculates a heart rate from a heartbeat component extracted by said heartbeat component extraction filter. 3. The heartbeat component extraction filter, wherein:
3. The electrical characteristic measuring device according to claim 1, wherein a signal having a frequency of 4.0 Hz is extracted. 4. A signal generating means for generating a measurement signal; a current measuring means for measuring a current flowing when the generated measurement signal is applied to a subject's body; Voltage measuring means for measuring a potential difference to be measured; calculating means for calculating bioelectric impedance from a current value measured by the current measuring means and a voltage value measured by the voltage measuring means; A respiratory component extraction filter for extracting a respiratory component from bioelectrical impedance, comprising: 5. The electrical characteristic measuring device according to claim 4, wherein said calculating means calculates a respiratory volume from a respiratory component extracted by said respiratory component extracting filter. 6. The respiratory component extraction filter, wherein:
The electrical characteristic measuring apparatus according to claim 4, wherein a signal having a frequency of 0.5 Hz is extracted. 7. The electrical characteristic measuring apparatus according to claim 2, wherein the calculating means calculates a movement amount or an energy metabolism amount from the calculated heart rate and the respiratory amount. 8. The electrical characteristic measuring apparatus according to claim 7, wherein said calculating means calculates a momentum or an energy metabolism as a linear combination of the heart rate and the respiration.