JP2003116802A - Electric characteristic measuring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric characteristic measuring system which can display a physical quantity based on a bioelectrical impedance as an interval estimate value, based on a bioelectrical impedance method. SOLUTION: A measuring signal generator 72 or the like generates a measuring signal, and charges the measuring signals to a subject through surface electrodes Hc and Lc which are conductively attached to surface areas at specified two locations being separated from each other of the subject. An I/V converter 91 or the like measures the current value of the measuring signal which is thrown into the subject. A differential amplifier 81 or the like measures the voltage value which is generated between the surface areas at the specified two locations being separated from each other of the subject. A CPU 3 calculates the bioelectrical impedance between the surface areas of the subject by the current value and the voltage value being respectively measured by the current and voltage measuring means, and calculates the physical amount based on the bioelectrical impedance. In addition, the CPU 3 output-controls the calculated physical quantity as the interval estimate value.

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 device, and more particularly, based on the bioelectrical impedance method,
The present invention relates to an electric characteristic measuring device capable of displaying a physical quantity based on bioelectrical impedance as an estimated section value.

[0002]

2. Description of the Related Art The present applicant has applied for a device using an M-sequence code as a bioelectrical impedance measuring device (Japanese Patent Laid-Open No. 10-14898). In the invention, the four-terminal A / D-converted signal is Fourier-transformed to measure the bioelectrical impedance at many frequencies to calculate the water content information inside and outside the cell.
Although not described in the specification for this device, the signal SN
In order to improve the ratio, the M-sequence signal is output many times and the signals are synchronously added.

The prior art will be described below. 2. Description of the Related Art In recent years, studies on electrical characteristics of living bodies have been conducted for the purpose of evaluating body composition of humans and animals. The electrical characteristics of the living body are remarkably different depending on the type of tissue or organ. For example, in the case of human, the electrical resistivity of blood is around 150 Ω · cm, whereas the electrical resistivity of bone and fat is 1 to 5 kΩ.・ C
There is also m. This electrical characteristic of the living body is called bioelectrical impedance, and is measured by passing a minute electric current between a plurality of electrodes mounted on the body surface of the living body.

A method for estimating body water distribution, body fat percentage, and body fat mass of a subject from the bioelectrical impedance thus obtained is called bioelectrical impedance method.
("Bioelectrical impedance method as an evaluation method of body composition", Baumgartner, RN, etc., "Bioelectrical impedance and its clinical application", Medical Electronics and Biotechnology, Kanai Hiroshi, 20 (3) Jun 1982, "Estimation of water distribution in the limbs 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 Kuchinomachi et al., 28 (3) 1992 etc.).

Bioelectrical impedance is derived from the resistance of an organism to the electrical current carried by the ions in the organism and the reactance associated with various types of polarization processes created by cell membranes, tissue interfaces, or non-ionized tissues. Composed. Capacitance, which is the reciprocal of the reactance, causes the current to lag the voltage rather than the voltage, creating a phase shift, which is the arctangent of the ratio of reactance to resistance (arctangent). It is quantified geometrically as a phase angle.

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

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

FIG. 6 is an electrical equivalent circuit diagram (equivalent circuit model) of the human body. In this figure, Cm represents cell membrane capacity, and Ri and Re represent intracellular fluid resistance and extracellular fluid resistance, respectively. At a low frequency f _L , the current mainly flows through the extracellular space, and the impedance Z becomes equal to the extracellular fluid resistance Re. At high frequency f _H , the electric current completely passes through the cell membrane, and the cell membrane capacity Cm is equivalent to being substantially short-circuited. Therefore, the impedance Z at high frequency f _H
Is equal to the combined resistance Ri · Re / (Ri + Re).

By the method described above, intracellular fluid resistance R
i and the extracellular fluid resistance Re can be determined, and based on these, the body fat state such as the body fat percentage, the fat weight, and the lean body mass and the body water distribution (intracellular fluid amount, extracellular fluid). It is possible to estimate the amount and total body water content). Further, changes in the body water distribution can be estimated by the changes in the resistances Re and Ri.

A bioelectrical impedance measuring apparatus for performing such estimation / estimation of each parameter by applying minute sinusoidal currents of a plurality of arbitrarily selected frequencies to a living body and processing the obtained signal by digital signal processing , Special table flat 6-50
The one described in Japanese Patent No. 6854 is known.

[0011]

The conventional bioelectrical impedance measuring devices are configured to display, for example, the body fat percentage as an estimated value, and the estimated value is the age, height, weight, etc. of the user. It is calculated from the bioelectrical impedance based on the body condition, but in reality, the most probable point estimation value in the population distribution is displayed.
However, when displayed by a measuring device which is a precision machine, the user tends to recognize the physical condition (for example, obese, lean, etc.) by using the estimated value as the true value of the user.

Since the estimated values of the body fat percentage and the like are calculated assuming a model, the changes over time can be measured relatively accurately, but the absolute value error is compared with the weight measured by a general scale. And big. According to the bioelectrical impedance method, an object of the present invention is to provide an electrical characteristic measuring device which allows a user to recognize the certainty of a physical quantity calculated based on the bioelectrical impedance and does not mislead the user. To provide.

[0013]

The electrical characteristic measuring device of the present invention comprises a signal generating means for generating a measuring signal, and a current measuring means for measuring a current flowing when the generated measuring signal is applied to the body of a subject. , A voltage measuring means for measuring a potential difference generated between predetermined surface parts of the body of the subject, a current value measured by the current measuring means and a voltage value measured by the voltage measuring means And a calculation means for calculating the estimated value and its certainty.

Since the certainty calculated by the calculating means is the section estimated value, the certainty of the estimated value can be displayed by a simple display. Further, since the probability that the calculation means calculates is the probability distribution of the estimated value, the probability of the estimated value can be displayed in a visually easy-to-see manner. Further, the computing means can know the bioelectrical characteristics of its position in the entire population by outputting the distribution of the population on which the computation is based.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The case where the electrical characteristic measuring apparatus of the present invention is applied to a bioelectrical impedance measuring apparatus will be described in detail.

FIG. 1 is a block diagram showing the electrical configuration of the bioelectrical impedance measuring apparatus according to this embodiment. The bioelectrical impedance measuring device includes a keyboard 1, a measurement processing unit 2, a CPU 3 (central processing unit), a display unit 4, a RAM 5, and a ROM 6.

The keyboard 1 is used to measure a measurement start switch for instructing the start of measurement by a measurer, input of human body characteristic items such as height, weight, sex and age of the subject, total measurement time T, measurement interval t, etc. It is composed of various keys for setting / changing the setting according to. 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 CPU 3.

The measurement processing unit 2 sends the probe current Ia to the body B of the subject as a measurement signal, and digitally processes the voltage / current information obtained from the body B of the subject. C
The PU 3 controls the entire bioelectrical impedance measuring apparatus, and calculates the bioelectrical impedance of the human body based on the processing result of the measurement processing unit 2, as well as various physical quantities relating to the body fat percentage and the body water distribution. Especially CPU
3 is the RAM 5 based on the calculated estimated value of the body fat percentage.
The width of the corresponding confidence interval is read from the estimated value table (see FIG. 2) stored in, and the display unit 4 controls the display.

The display unit 4 displays the bioelectrical impedance of the body B of the subject calculated by the CPU 3, the body fat percentage and the body water content. In particular, the display unit 4
Based on an instruction from the CPU 3, the section estimated value of the body fat percentage is displayed. In the present embodiment, the estimated value is displayed together with the confidence interval width ± α [%] of the confidence level of 95% (see FIG. 4).

The RAM 5 stores various data (eg, height, weight, sex of the subject, amount of extracellular fluid or intracellular fluid, etc.).
Is set, and a work area of the CPU 3 is set. In particular, the RAM 5 stores the personal data and the above-described estimated value table for creating the distribution (see FIG. 4B) of the relevant population according to the body condition such as the height and weight of the subject. The ROM 6 fixedly stores the processing program of the CPU 3.

FIG. 2 is a diagram illustrating an estimated value table. In this figure, the estimated value [%] of the body fat percentage calculated by the CPU 3 and the width [%] of the confidence interval displayed in pair with the estimated value are displayed. The width of this confidence interval depends on the corresponding estimate.

In this example, the width ± 5 [%] of the confidence interval is stored for the estimated value 20 [%]. Thereby, when the calculated estimated value of the body fat percentage is 21 [%], the CPU 3
Is the width of the confidence interval corresponding to the nearest estimated value 20 [%] ±
5 [%] is read out and the section estimation value “21 [%] ±
5 [%] ”(see FIG. 4A). Although the estimated values 20, 30, 40 [%] and the widths of the confidence intervals corresponding to them are stored in the example of FIG. , The width of the estimated value and the confidence interval can be made smaller, and can be set arbitrarily.

Next, the detailed configuration of the measurement processing unit 2 will be described. The measurement processing unit 2 is composed of an output processing circuit and an input processing circuit. The output processing circuit includes a PIO (parallel interface) 71, a measurement signal generator 72, a low pass filter (LPF) 73, and a coupling capacitor 74. The input processing circuit includes coupling capacitors 80a, 80b and 90, a differential amplifier 81, a current / voltage (I / V) converter 91, analog anti-aliasing filters LPFs 82 and 92, and an A / D converter. 83, 93, and sampling memories (ring buffers) 84, 94.

First, the output processing circuit will be described. The measurement signal generator 72 is a PIO 71 such as a bus line.
Connected to the CPU 3 via an output resistance of 10 kΩ or more over the entire region of the generated signal frequency. The measurement signal generator 72 is a CPU via the PIO 71.
The signal generation instruction from 3 is input, and the probe current Ia of the longest linear signal (M series: Maximum Linear Codes series) is repeatedly generated a predetermined number of times. Generated probe current Ia
Is input to the LPF 73.

Probe current I from the measurement signal generator 72
The high frequency noise component and the direct current component of a are removed by the LPF 73 and the coupling capacitor 74, and are sent to the surface electrode Hc as a measurement signal, and the body B of the subject is measured.
(See FIG. 3). The value of the probe current is, for example, 500 to 800 μA.

Further, in the present embodiment, the number of times the probe current Ia (measurement signal) is repeated is 1 to 256 times per signal generation instruction. The number of repetitions may be arbitrarily set by the measurer using the keyboard 1. The higher the number of repetitions, the higher the accuracy, but even if it is a minute current, it may adversely affect the human body when it is continuously applied to the human body for a long time. Therefore, it is preferably 1 to 256 times.

Here, the M-sequence signal will be described. M
The sequence signal is a code signal generally used in a spread spectrum communication system and a spread spectrum distance measuring system, and is the longest code sequence generated by a shift register or a delay element having a certain length.

A binary M-sequence signal generator for generating 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 an n-stage state. It is composed of a logic circuit (exclusive logic circuit) for returning the logical combination to the input of the shift register. The output of the M-sequence signal generator and the state of each stage at a certain sample time (clock time) are a function of the output of the feedback stage at the immediately preceding sample time.

Probe current Ia using this M-sequence signal
Despite having many frequency components, the energy is dispersed for about 1 msec, so that it does not damage the living body.
Further, since it occurs at a time interval sufficiently shorter than the pulse or respiratory cycle, it is not affected by these. In addition, since the amplitude of the frequency spectrum of the M-sequence signal is substantially flat over the entire frequency band, the frequency characteristic of the SN ratio is also substantially flat.

FIG. 3 is a diagram schematically showing a usage state of the bioelectrical impedance measuring device according to the present embodiment. Here, the connection between each of the output processing circuit described above and the input processing circuit described below and the body B of the subject will be briefly described. At the time of measurement, the surface electrode Hc is electrically conductively attached to the back part H of the subject by an adsorption method, and the surface electrode Lc is electrically conductively attached to the right instep part L by an adsorption method. Therefore, the measurement signal enters the body B from the right hand part of the subject.

The surface electrode Hp is conductively attached to the right hand back H of the subject by the suction method, and the surface electrode Lp is conductively attached to the right back L by the suction method. . At this time, the surface electrodes Hc and Lc are attached to a part farther from the center of the human body than the surface electrodes Hp and Lp. The surface electrodes Hp, Lp, Hc, Lc are connected to the bioelectrical impedance measuring device by a measuring cable 10.

Next, the input processing circuit will be described.
The surface electrode Hp is conductively attached to the back part H of the right side of the subject by the suction method, while the surface electrode Lp is
It is electrically conductively attached to the right instep L by a suction method.

The differential amplifier 81 (see FIG. 1) detects the potential (potential difference) between the two surface electrodes Hp and Lp. That is, when the measurement signal is sent to the body B of the subject, the differential amplifier 81 detects the voltage Vp between the right limb of the subject and L
Input to PF82. This voltage Vp is a voltage drop due to the bioelectrical impedance of the body B of the subject between the surface electrode Hp and the surface electrode Lp.

The LPF 82 removes high frequency noise from the voltage Vp and supplies it to the A / D converter 83. LPF
The cutoff frequency of 82 is lower than half the sampling frequency of the A / D converter 83. As a result, aliasing noise generated in the A / D conversion processing by the A / D converter 83 is removed.

Each time the CPU 3 supplies the digital conversion signal Sd, the A / D converter 83 converts the noise-removed voltage Vp into a digital signal at a predetermined sampling period, and digitizes the voltage Vp. Are supplied to the sampling memory 84 every sampling cycle.

Next, the surface electrode Lc (see FIG. 3) is attached to the right instep L of the subject by the suction method.
The surface electrode Lc and the coupling capacitor 90 (see FIG. 1) are connected by a coaxial cable (not shown), and the shield portion of the coaxial cable is grounded.

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 measurement signal (probe current Ia) is sent to the body B of the subject, the I / V converter 91 detects the probe current Ia flowing between the right limbs of the subject, converts it into the voltage Vc, and then the LPF 92. Supply to.

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. Also in this case, A /
The aliasing noise generated in the A / D conversion processing by the D converter 93 is removed.

Each time the CPU 3 supplies the digital conversion signal Sd, the A / D converter 93 converts the noise-removed voltage Vc into a digital signal at a predetermined sampling period, and digitizes the voltage Vc. Are supplied to the sampling memory 94 every sampling cycle. A mentioned above
The measurement by the / D converters 83, 93 and the like is started in response to an instruction from the CPU 3 after a predetermined time elapses from when the measurement signal is sent to the body B of the subject until the transient phenomenon stabilizes.

The CPU 3 controls the output processing circuit according to the processing program stored in the ROM 6 to continuously send the measurement signal to the body B of the subject, and controls the input processing circuit to initially wait for the measurement. To After that, the detected voltages Vp and Vc are sampled a predetermined number of times at a predetermined sampling cycle, and then various physical quantities such as bioelectrical impedances described below are calculated.

First, the voltages Vp and Vc, which are functions of time, stored in the sampling memories 84 and 94 are sequentially read out and subjected to Fourier transform, respectively, to obtain the voltages Vp (f) and Vc (f) (which are functions of frequency). (f is the measurement frequency)
After the conversion, the averaging is performed to calculate the bioelectrical impedance Z (f) [= Vp (f) / Vc (f)] for each frequency.

Next, the CPU 3 plots the bioelectrical impedance Z (f) for each frequency, and further performs curve fitting by making use of a calculation method such as the least squares method to obtain the impedance locus D (see FIG. 5). Ask for.
Further, from the obtained impedance locus D, the bioelectric impedance R0 of the body B of the subject at the time of frequency 0 and the bioelectric impedance R∞ at the time of infinite frequency are calculated,
From the calculation results, the intracellular fluid resistance and the extracellular fluid resistance of the body B of the subject are calculated.

Further, based on the calculated intracellular fluid resistance and extracellular fluid resistance, and the human body characteristic data such as the height, weight, sex and age of the subject inputted from the keyboard 1, etc. Using the built-in body composition estimation formula, the body fat percentage, fat weight, lean body mass, intracellular fluid volume, extracellular fluid volume of the subject's body B and the total body water content (body fluid volume) And calculate the physical quantity.
In the present embodiment, the calculated body fat percentage is displayed by numbers and a graph on display unit 4 (for example, LCD) having a display controller (see FIG. 4).

Next, the operation of the bioelectrical impedance measuring device according to this embodiment will be described. First, prior to the measurement, as shown in FIG. 3, two surface electrodes Hc and Hp are used.
On the right hand part H of the subject, two surface electrodes Lp, Lc
Is attached to the right instep L of the subject by the suction method. At this time, the front surface electrodes Hc and Lc are
Attach it to a part farther from the center of the human body than p and Lp.

Next, the measurer (or the subject himself) turns on the measurement start switch of the keyboard 1. C
The PU 3 first sends a signal generation instruction signal to the measurement signal generator 72 after performing a predetermined initial setting. This initial setting includes the total number of samples in the impedance locus D (see FIG. 5) described above, the sampling cycle of the A / D converters 83 and 93, the process of calculating the generation timing of the digital conversion signal Sd, and the like.

As a result, the measurement signal generator 72 repeatedly generates the probe current Ia (measurement signal) a predetermined number of times,
A measurement signal is transmitted to the surface electrode Hc (see FIG. 3) attached to the back H of the subject through the LPF 73, the coupling capacitor 74, and the measurement cable 10 that is a double shielded wire. As a result, a measurement signal of about 500 to 800 μA flows through the body B of the subject from the surface electrode Hc.

When the measurement signal Ia is applied to the body B of the subject, in the differential amplifier 81 of the measurement processing unit 2, the voltage Vp generated between the right limb to which the surface electrodes Hp and Lp are attached.
Is detected and supplied to the A / D converter 83 via the LPF 82. On the other hand, in the I / V converter 91, the surface electrode H
After the probe current Ia flowing between the right limbs to which c and Lc are attached is detected and converted into the voltage Vc, the LPF 9
It is then supplied to the A / D converter 93 via 2. At this time, C
From the PU3, the A / D converter 8 is supplied every sampling cycle.
The digital conversion signal Sd is supplied to 3, 93.

Each time the A / D converter 83 receives the supply of the digital conversion signal Sd, it converts the voltage Vp into a digital signal and supplies it to the sampling memory 84. The sampling memory 84 sequentially stores the digitized voltage Vp. On the other hand, in the A / D converter 93, each time the digital conversion signal Sd is supplied, the voltage Vc is converted into a digital signal and supplied to the sampling memory 94. The sampling memory 94 sequentially stores the digitized voltage Vc.

The CPU 3 uses the probe current (measurement signal) I
When the number of repetitions of a reaches a preset number, the measurement is stopped, and then the voltage Vp, which is a function of time, stored in the sampling memories 84 and 94 is first stored.
The voltages Vp (f) and Vc (f), which are functions of frequency, are sequentially read out by Vc and subjected to Fourier transform processing.
(F is a frequency) and then averaged to obtain bioelectrical impedance Z (f) (= Vp (f) /
Vc (f)) is calculated.

Next, the CPU 3 performs curve fitting based on the calculated bioelectrical impedance Z (f) for each frequency by a calculation method such as the least squares method to obtain the impedance locus D shown in FIG. From the obtained impedance locus D, the bioelectrical impedance R0 of the body B of the subject at time 0 and the bioelectrical impedance R∞ at infinite frequency (the X-axis coordinate value of the point where the arc of the impedance locus D intersects the X-axis). Equivalent to) and
The intracellular fluid resistance and extracellular fluid resistance of the body B of the subject are calculated from the calculation results.

Further, the CPU 3 pre-processes a program based on the calculated intracellular fluid resistance and extracellular fluid resistance, and the human body characteristic data such as the height, weight, sex and age of the subject input from the keyboard 1. Using the body composition estimation formula incorporated in the body, the body fat percentage, fat weight, lean body weight, intracellular fluid resistance, extracellular fluid resistance of the subject's body B and the total body water content ( The amount of body fluid) is calculated. Then, each calculated data is stored in the RAM 5 and displayed on the display unit 4. In the present embodiment, the CPU 3 calculates, based on the calculated estimated value of the body fat percentage,
The width of the relevant confidence interval is read from the estimated value table stored in the RAM 5.

FIG. 4 is a view for explaining a display example of the accuracy of the body fat percentage displayed by the bioelectrical impedance measuring device according to this embodiment. Based on the calculated estimated value and the width of the read confidence interval, the CPU 3 calculates from FIG.
As illustrated in “Your body fat percentage is 21 [%] ± 5
[%]is. The estimated section value is displayed on the display unit 4 in the format of "."
As illustrated in (b), the distribution of the estimated value that the subject corresponds to the distribution of the population is displayed in a graph format. As a result, the subject can correctly recognize the interval estimated value as the statistical data without being restricted only by the estimated value as the statistical data.

Next, the CPU 3 judges whether or not the total measurement time T has passed, and if it is concluded that the time has passed, then
The subsequent measurement process ends. If it has not elapsed, the same measurement process is started again after waiting for the time t corresponding to the measurement interval to elapse. The above process is repeated until the total measurement time T has elapsed. Although the embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and changes in design within the scope not departing from the gist of the present invention, etc. There may be.

For example, in the above-described embodiment, the current value applied to the subject is measured via the front surface electrode Hc and the front surface electrode Lc, and the surface at two predetermined positions is measured via the front surface electrode Hp and the front surface electrode Lp. The voltage value generated between the parts is measured. The present invention is not limited to this, and for example, the current value and the voltage value may be measured by the surface electrode Hc and the surface electrode Lc (so-called two-terminal method),
The number of surface electrodes is not a limitation of the present invention. Also,
The place where the electrode is attached is not limited to the hands and feet.

In the above embodiment, the CPU 3 calculates the bioelectrical impedance as the bioelectrical parameter, and calculates the body fat percentage by calculating the impedance locus, the extracellular fluid resistance and the intracellular fluid resistance. . The present invention is not limited to this, even if the bioelectrical admittance is calculated, and the body fat percentage is calculated by calculating the admittance locus, the temporal change amount such as the extracellular fluid resistance and the intracellular fluid resistance, and a part thereof. Good.

In the above embodiment, the bioelectrical impedance measuring device calculates the body fat percentage from the calculated bioelectrical impedance. The present invention is not limited to this, and can be applied to, for example, the one in which the estimated value is calculated by a statistical method such as the body water distribution described above. Further, although the CPU 3 performs the Fourier transform processing in the above-described embodiment, the present invention is not limited to this, and an arithmetic method for converting a function shown in the time domain into a function shown in the frequency domain is used. Anything will do.

Further, in the above embodiment, the case where the height, weight, sex and age of the subject are input as the human body characteristic items has been described, but the sex, age, etc. may be omitted if necessary. Alternatively, items such as race may be added. The calculated bioelectric parameter of the human body may be output to the printer. Further, a pulse wave sensor or a sensor capable of detecting the breathing cycle may be attached to the human body, and the measurement timing may be set by the output signal of each sensor.

In the above embodiment, the calculation result is displayed on the display unit, but the calculation result may be printed directly on the printer. From the above, the electrical characteristic measuring apparatus of the present invention is the measuring signal supplying means (the measuring signal generator 72).
Etc.), current measuring means (I / V converter 91 etc.), voltage measuring means (differential amplifier 81 etc.), and computing means (CPU3).
It is composed of

The measurement signal supply means generates a measurement signal,
A measurement signal is input to the subject via surface electrodes Hc and Lc that are electrically conductively attached to two predetermined surface portions of the subject that are separated from each other. The current measuring means measures the current value of the measurement signal input to the subject. The voltage measuring means measures a voltage value generated between two predetermined surface portions of the subject which are separated from each other. The calculation means calculates the bioelectrical impedance between the surface parts of the subject based on the current value and the voltage value respectively measured by the current and voltage measuring means, and calculates the physical quantity based on the bioelectrical impedance. Here, the arithmetic means controls the output of the calculated physical quantity as an estimated section value.

[0060]

As described above, according to the electrical characteristic measuring apparatus of the present invention, the statistically calculated estimated value of the body fat percentage or the like and its certainty can be displayed, and the user can display it. It is possible to correctly recognize the certainty of the numerical values to be equalized.

[Brief description of drawings]

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

FIG. 2 is a diagram illustrating an estimated value table.

FIG. 3 is a diagram schematically showing a usage state of the bioelectrical impedance measuring device according to the embodiment of the present invention.

FIG. 4 is a diagram illustrating a display example of the accuracy of the body fat percentage displayed by the bioelectrical impedance measurement device according to the present embodiment.

FIG. 5 is a diagram illustrating an impedance locus.

FIG. 6 is an electrical equivalent circuit diagram (equivalent circuit model) of a human body.

[Explanation of symbols]

1 keyboard 2 Measurement processing unit 3 CPU 4 Display 5 RAM 6 ROM 10 Measurement cable 71 PIO 72 Measurement signal generator 73 LPF 74, 80a, 80b, 90 Coupling capacitor 81 Differential amplifier 82,92 LPF 83,93 A / D converter 84,94 sampling memory Hc, Lc, Hp, Lp surface electrode

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Claims (4)

[Claims] 1. 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 body of a subject, and a current generating means generated between predetermined surface parts of the body of the subject. Voltage measuring means for measuring the potential difference, and a calculating means for calculating the estimated value of the bioelectric property and its certainty from the current value measured by the current measuring means and the voltage value measured by the voltage measuring means, An electrical characteristic measuring device comprising: 2. The probability that the calculation means calculates is
The electrical characteristic measuring device according to claim 1, wherein the electrical characteristic measuring device is a section estimated value. 3. The probability that the calculation means calculates is
The electrical characteristic measuring device according to claim 1, wherein the electrical characteristic measuring device is a probability distribution of estimated values. 4. The electrical characteristic measuring apparatus according to claim 1, wherein the calculation unit outputs a distribution of a population which is a source of calculation.