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Analogue demodulation mode mixing biological impedance measuring method

A measurement method and bio-impedance technology, applied in diagnostic recording/measurement, medical science, sensors, etc., can solve the problem of inability to accurately reflect the electrical impedance information of biological organisms, the electrical impedance information of biological tissues cannot fully reflect the status of organisms, and cannot be analyzed, etc. question

Inactive Publication Date: 2007-08-29
TIANJIN UNIV
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Problems solved by technology

In order to obtain intracellular information, it is necessary to use the characteristics of high-frequency current flowing through the intracellular and extracellular fluids, so the electrical impedance information of biological tissues measured at a single excitation frequency cannot fully reflect the status of organisms
At present, the multi-frequency excitation mode is mostly used, that is, signals of different frequencies are used for excitation, and the biological impedance of this frequency is measured, but the human body is dynamic, and this method cannot analyze the information of the same life activity under different excitation frequencies, and different When the measurement frequency point is switched, the establishment time of the bioelectrical impedance information measurement at the new frequency is longer, so the data provided by this time-sharing measurement method cannot accurately reflect the electrical impedance information of the organism at a certain moment

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  • Analogue demodulation mode mixing biological impedance measuring method
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  • Analogue demodulation mode mixing biological impedance measuring method

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Embodiment Construction

[0029] In this embodiment, the angular frequencies of the frequency mixing current excitation signal are ω 1 and ω 2 .

[0030] for ω 1 frequency, V r1 output signal for reference signal 1, V r2 The output signal is the reference signal 2, and the two are orthogonal to form a virtual reference vector. The amplitude of the two reference signals is 1, which can be expressed as:

[0031] V r1 = sin ω 1 t, V r2 =cosω 1 t

[0032] Using the analog multiplication demodulation method respectively, the voltage V H and V L are the voltage signals on the measured impedance and the reference resistor respectively, according to the measurement method in Figure 2, measure the voltage V H and V L of V r1 and V r2 For the real and imaginary parts of the reference, the measured V Hout2 is 1.73 volts, V Hout1 1 volt, V Lout2 0.5 volts, V Lout1 is 0.87 volts, V can be obtained according to the following formula H and V L The magnitude and phase of , where, Φ H 、A H is the ...

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Abstract

The present invention relates to a frequency mixing biological impedance measuring method based on analog demodulation mode. Said invention adopts the frequency mixing current of high and low two frequencies to make excitation. Besides, said invention also provides the concrete steps of implementing said measuring method by combining virtual reference vector method and analog demodulation mode.

Description

technical field [0001] The invention belongs to the field of biological information detection, and in particular relates to a method for measuring biological electrical impedance by using an analog demodulation mode under a frequency mixing excitation mode. Background technique [0002] Bioelectrical impedance measurement technology is a non-destructive detection technology that uses the electrical properties (impedance, admittance, dielectric constant, etc.) and changes of biological tissues and organs to extract biomedical information related to human physiological and pathological conditions. In the early days, the single-frequency excitation mode was mainly used. According to the frequency impedance characteristics of biological tissues, the cell membrane capacitance is basically stable in the β dispersion range. As the frequency increases, the capacitive reactance of the membrane capacitance decreases, and the applied current bypasses the cell membrane at low frequencies...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): A61B5/053
Inventor 王超王化祥
Owner TIANJIN UNIV