A Physical Equivalent Circuit Design Method for Biological Fluids

Abstract

This application relates to a physical equivalent circuit design method for biological fluids. The method involves testing the biological fluid at a preset frequency to obtain impedance and phase test values. An initial equivalent circuit is established based on these impedance and phase test values. The initial parameter values ​​of the equivalent components in the initial equivalent circuit are then corrected using preset parameter relationships to obtain the physical parameter values ​​of the equivalent components. Finally, the physical equivalent circuit is constructed using the physical parameter values ​​and the types and connections of the equivalent components in the initial equivalent circuit. This allows the constructed physical equivalent circuit to replace biological fluid samples in testing biological detection and analysis instruments, effectively improving the performance testing efficiency of these instruments and consequently, significantly enhancing the research and development and manufacturing efficiency of biological detection and analysis instruments.

Description

Technical Field

[0001] This application belongs to the field of medical device testing technology, and in particular relates to a physical equivalent circuit design method for biological fluid. Background Technology

[0002] Biological detection and analysis instruments can be used to detect the concentration of a specific substance in human blood or tissue fluid, providing information for clinical diagnosis, treatment, prognosis, and health status. The research and development and manufacturing of biological detection and analysis instruments require extensive performance testing.

[0003] In the existing technology, during the research and development and manufacturing process of biological detection and analysis instruments, biological fluid samples such as blood or tissue fluid are generally used to test the detection performance of the instruments. For the detection of the concentration of certain substances, it is necessary to first catalyze the biological fluid sample with a catalyst, and then use the biological detection and analysis instrument to detect the specific response of the biological fluid sample to a preset frequency signal to detect the concentration of the specific substance in the biological fluid sample. The performance test result of the biological detection and analysis instrument is then determined based on the detected concentration of the specific substance. Since the biological fluid sample cannot be repeatedly tested after catalysis, it is impossible to determine whether the abnormal performance test result is due to a defect in the biological detection and analysis instrument itself or an abnormality in the biological fluid sample, resulting in low performance testing efficiency of the biological detection and analysis instrument.

[0004] Therefore, how to improve the performance testing efficiency of biological detection and analysis instruments is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this application is to provide a physical equivalent circuit design method for biological fluids. The physical equivalent circuit design method for biological fluids provided by this application can effectively improve the performance testing efficiency of biological detection and analysis instruments, and thus effectively improve the research and development and manufacturing efficiency of biological detection and analysis instruments.

[0006] The technical solution provided in this application is as follows:

[0007] A method for designing a physical equivalent circuit for a biological fluid, comprising:

[0008] The biological fluid was tested at a preset frequency to obtain the impedance and phase test values ​​of the biological fluid.

[0009] Based on the impedance and phase test values, an initial equivalent circuit of the biological fluid is established. The initial equivalent circuit includes the types, connection relationships, and initial parameter values ​​of multiple equivalent elements.

[0010] Based on the initial parameter values ​​and the preset parameter relationship, the physical parameter values ​​of multiple equivalent elements of the initial equivalent circuit are obtained;

[0011] Based on the physical parameter values, the types and connection relationships of the multiple equivalent elements of the initial equivalent circuit, a physical equivalent circuit of the biological fluid is constructed.

[0012] Preferably, the initial equivalent circuit of the biological fluid is established based on the impedance and phase test values. The initial equivalent circuit includes the types, connection relationships, and initial parameter values ​​of multiple equivalent elements, including:

[0013] Based on the impedance and phase test values, an initial equivalent circuit of the biological fluid, including the types and connection relationships of multiple equivalent elements, is constructed.

[0014] Based on the types and connection relationships of the multiple equivalent elements, the relationship between the impedance parameters of the initial equivalent circuit and the circuit parameters of the multiple equivalent elements is obtained;

[0015] Based on the impedance and / or phase test values ​​and the circuit parameter relationships, the initial parameter values ​​of the plurality of equivalent elements in the initial equivalent circuit are obtained.

[0016] Preferably, the preset parameter relationship is determined by the following method:

[0017] The impedance and phase experimental test values ​​of the experimental physical equivalent circuit are obtained by testing at a preset frequency. The experimental physical equivalent circuit is a circuit made based on the initial equivalent circuit of the experimental biological fluid.

[0018] Based on the initial parameter values ​​of multiple equivalent elements of the initial equivalent circuit of the experimental biological fluid and the circuit parameter relationship, the impedance and phase calculation values ​​are obtained.

[0019] The impedance and phase deviations are obtained based on the experimentally measured impedance and phase values ​​and the calculated impedance and phase values.

[0020] Based on the impedance and phase deviation, adjust the initial parameter values ​​of the equivalent elements of the initial equivalent circuit of the experimental biological fluid until the absolute values ​​of the impedance and phase deviation are less than the preset absolute value of the deviation. Then, use the adjusted initial parameter values ​​as the physical parameter values ​​of the equivalent elements of the initial equivalent circuit of the experimental biological fluid.

[0021] By changing the experimental biological fluid with different impedances and phase characteristics, the above steps are repeated to obtain multiple sets of initial parameter values ​​and physical parameter values ​​with corresponding relationships. A functional relationship is established based on the multiple sets of initial parameter values ​​and physical parameter values ​​with corresponding relationships, and the functional relationship is used as the preset parameter relationship.

[0022] Preferably, the initial equivalent circuit includes a first resistor, a second resistor, a first capacitor, and a second capacitor, wherein:

[0023] The first resistor and the first capacitor connected in series are connected in parallel with the second resistor.

[0024] The second capacitor is connected in parallel with the second resistor.

[0025] Preferably, the impedance parameter includes a real part and an imaginary part of the impedance, and the circuit parameter relationship includes a relationship for the real part of the impedance and a relationship for the imaginary part of the impedance. The step of obtaining the impedance parameter relationship between the initial equivalent circuit and the circuit parameter relationship of the multiple equivalent elements based on their types and connections includes:

[0026] Based on the types and connection relationships of the multiple equivalent elements, determine the first circuit impedance relationship between the impedance of the initial equivalent circuit and the real and imaginary parts of the impedance;

[0027] Based on the connection relationship of the plurality of equivalent elements, a second circuit impedance relationship is determined between the impedance of the initial equivalent circuit and the impedance of the plurality of equivalent elements.

[0028] Based on the types of the plurality of equivalent elements, determine the element impedance relationship between the impedance of each of the plurality of equivalent elements and the parameters of the corresponding equivalent element;

[0029] Based on the first circuit impedance relationship, the second circuit impedance relationship, and the component impedance relationship, the impedance real part relationship between the real part of the impedance and the parameters of the multiple equivalent components, and the impedance imaginary part relationship between the imaginary part of the impedance and the parameters of the multiple equivalent components are obtained.

[0030] Preferably, the impedance test value includes the real part impedance test value and the imaginary part impedance test value. The step of obtaining the initial parameter values ​​of the plurality of equivalent elements in the initial equivalent circuit based on the impedance and / or phase test values ​​and the circuit parameter relationship includes:

[0031] Based on the measured values ​​of the real part of the impedance, the measured values ​​of the imaginary part of the impedance, the relationship between the real part of the impedance and the relationship between the imaginary part of the impedance, the initial parameter values ​​of the multiple equivalent elements in the initial equivalent circuit are obtained.

[0032] Preferably, the impedance parameter further includes phase and magnitude, and the circuit parameter relationship further includes phase relationship and magnitude relationship. After obtaining the impedance real part relationship between the real part of the impedance and the parameters of the plurality of equivalent elements, and the impedance imaginary part relationship between the imaginary part of the impedance and the parameters of the plurality of equivalent elements, based on the first circuit impedance relationship, the second circuit impedance relationship, and the element impedance relationship, the method further includes:

[0033] Based on the real part of the impedance relationship and the imaginary part of the impedance relationship, the phase relationship between the phase and the parameters of the multiple equivalent elements, and the magnitude relationship between the magnitude and the parameters of the multiple equivalent elements are obtained.

[0034] Preferably, the impedance test value further includes a magnitude test value, and the step of obtaining the initial parameter values ​​of the plurality of equivalent elements in the initial equivalent circuit based on the impedance and / or phase test values ​​and the circuit parameter relationship includes:

[0035] Based on the magnitude test value, the phase test value, the phase relation, and the magnitude relation, the initial parameter values ​​of the multiple equivalent elements in the initial equivalent circuit are obtained.

[0036] Preferably, obtaining the initial parameter values ​​of the plurality of equivalent elements in the initial equivalent circuit based on the impedance and / or phase test values ​​and the circuit parameter relationship includes:

[0037] Based on the measured values ​​of the real part of the impedance, the measured values ​​of the imaginary part of the impedance, the measured values ​​of the phase, the measured values ​​of the magnitude, the relationship between the real part of the impedance, the relationship between the imaginary part of the impedance, the relationship between the phase, and the relationship between the magnitude, the initial parameter values ​​of the multiple equivalent elements in the initial equivalent circuit are obtained.

[0038] Preferably, the impedance real part relationship is as follows:

[0039]

[0040] Where R is the real part of the impedance, π is pi, f is the frequency, C1 is the capacitance of the first capacitor, C2 is the capacitance of the second capacitor, R1 is the resistance of the first resistor, and R2 is the resistance of the second resistor.

[0041] The specific relationship of the imaginary part of the impedance is as follows:

[0042]

[0043] Where X is the imaginary part of the impedance, π is pi, f is the frequency, C1 is the capacitance of the first capacitor, C2 is the capacitance of the second capacitor, R1 is the resistance of the first resistor, and R2 is the resistance of the second resistor.

[0044] Compared with existing technologies, this application provides a physical equivalent circuit design method for biological fluids. This method involves testing the biological fluid at a preset frequency to obtain impedance and phase test values. An initial equivalent circuit is established based on these impedance and phase test values. The initial parameter values ​​of the equivalent components in the initial equivalent circuit are then corrected using preset parameter relationships to obtain the physical parameter values ​​of the equivalent components. Finally, a physical equivalent circuit is constructed using these physical parameter values ​​and the types and connections of the equivalent components in the initial equivalent circuit. This allows the constructed physical equivalent circuit to replace biological fluid samples in testing biological detection and analysis instruments, effectively improving the performance testing efficiency of these instruments and consequently, significantly enhancing the research and development and manufacturing efficiency of biological detection and analysis instruments. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is a flowchart illustrating a physical equivalent circuit design method for a biological fluid disclosed in an embodiment of this application.

[0047] Figure 2 This is a circuit diagram of the initial equivalent circuit disclosed in the embodiments of this application. Detailed Implementation

[0048] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0049] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on or indirectly set on the other component; when a component is referred to as "connected to" another component, it can be directly connected to or indirectly connected to the other component.

[0050] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0051] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "a plurality of" or "several" means two or more, unless otherwise explicitly specified.

[0052] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0053] like Figure 1 As shown, this application provides a physical equivalent circuit design method for a biological fluid, including:

[0054] S2. Test the biological fluid at a preset frequency to obtain the impedance and phase test values ​​of the biological fluid;

[0055] In this embodiment, a test analyzer (such as an impedance analyzer) can be used to test biological fluids such as blood or tissue fluid at a preset frequency to obtain the impedance test value and phase test value of the biological fluid. The preset frequency can be a pre-set frequency or multiple different frequencies within a specific range. That is, the obtained impedance test value and phase test value of the biological fluid can be a set of data corresponding to the frequency or multiple sets of data corresponding to multiple different frequencies. The impedance test value can include the real part of the impedance, the imaginary part of the impedance, and the magnitude of the impedance.

[0056] S4. Based on the impedance and phase test values, establish the initial equivalent circuit of the biological fluid. The initial equivalent circuit includes the types, connection relationships and initial parameter values ​​of multiple equivalent components.

[0057] In this embodiment, the impedance and phase characteristics of the biological fluid can be analyzed first based on the impedance and phase test values ​​to construct an initial equivalent circuit of the biological fluid, including the types and connections of multiple equivalent components. Then, based on the types and connections of the multiple equivalent components, the relationship between the impedance parameters of the initial equivalent circuit and the circuit parameters of the multiple equivalent components can be obtained. Then, based on the impedance and / or phase test values ​​and the circuit parameter relationship, the initial parameter values ​​of the multiple equivalent components in the initial equivalent circuit can be obtained. If the equivalent components in the initial equivalent circuit are capacitors and resistors, the initial parameter values ​​are the capacitance value of the capacitor and the resistance value of the resistor.

[0058] S6. Based on the initial parameter values ​​and the preset parameter relationship, obtain the physical parameter values ​​of multiple equivalent elements of the initial equivalent circuit;

[0059] In this embodiment, since parasitic capacitance is easily generated when the physical equivalent circuit is tested at high frequency, or due to other reasons, there is a deviation between the initial parameter value of the initial equivalent circuit and the physical parameter value of the physical equivalent circuit. The initial parameter values ​​of multiple equivalent elements or a single equivalent element in the initial equivalent circuit can be corrected according to the preset parameter relationship, and then the physical parameter values ​​of multiple equivalent elements in the initial equivalent circuit can be obtained according to the corrected initial parameter values.

[0060] In this embodiment, the preset parameter relationship can be a function relationship established based on multiple sets of corresponding initial parameter values ​​and physical parameter values ​​determined by experimental verification using multiple biological fluid samples, and then used as the preset parameter relationship.

[0061] S8. Based on the physical parameter values, the types and connection relationships of multiple equivalent elements of the initial equivalent circuit, construct the physical equivalent circuit of the biological fluid.

[0062] Compared with existing technologies, this application provides a physical equivalent circuit design method for biological fluids. This method involves testing the biological fluid at a preset frequency to obtain impedance and phase test values. An initial equivalent circuit is established based on these impedance and phase test values. The initial parameter values ​​of the equivalent components in the initial equivalent circuit are then corrected using preset parameter relationships to obtain the physical parameter values ​​of the equivalent components. Finally, a physical equivalent circuit is constructed using these physical parameter values ​​and the types and connections of the equivalent components in the initial equivalent circuit. This allows the constructed physical equivalent circuit to replace biological fluid samples in testing biological detection and analysis instruments, effectively improving the performance testing efficiency of these instruments and consequently, significantly enhancing the research and development and manufacturing efficiency of biological detection and analysis instruments.

[0063] like Figure 2As shown, in one embodiment of this application, the initial equivalent circuit includes a first resistor R1, a second resistor R2, a first capacitor C1, and a second capacitor C2, wherein:

[0064] The first resistor R1 and the first capacitor C1 connected in series are connected in parallel with the second resistor R2.

[0065] The second capacitor C2 is connected in parallel with the second resistor R2.

[0066] In this embodiment, the first end of the first resistor R1 is connected to the first end of the second resistor R2 and the first end of the first capacitor C1 respectively; the second end of the first resistor R1 is connected to the first end of the first capacitor C1; and the second end of the first capacitor C1 is connected to the second end of the second resistor R2 and the second end of the second capacitor C2 respectively.

[0067] As one implementation method, in this embodiment of the application, step S4 includes:

[0068] S41. Based on the impedance and phase test values, construct an initial equivalent circuit for the biological fluid, including the types and connection relationships of multiple equivalent components.

[0069] In this embodiment, the impedance and phase characteristics of the biological fluid are analyzed based on impedance and phase test values. An initial equivalent circuit of the biological fluid, including the types and connections of multiple equivalent components, is constructed. The constructed initial equivalent circuit can be... Figure 2 The circuit shown.

[0070] S42. Based on the types and connection relationships of multiple equivalent elements, obtain the relationship between the impedance parameters of the initial equivalent circuit and the circuit parameters of multiple equivalent elements.

[0071] In this embodiment, the impedance parameter may include the real part and the imaginary part of the impedance, and the circuit parameter relationship may include the impedance real part relationship and the impedance imaginary part relationship, which can be based on... Figure 2Knowing that the initial equivalent circuit is a two-port network, based on the impedance and phase characteristics of the two-port network, the impedance of the initial equivalent circuit is determined to be a complex impedance including both the real and imaginary parts of the impedance. This leads to the first circuit impedance relationship of the initial equivalent circuit. Based on the series and parallel connections of multiple equivalent elements, the relationship between the total impedance of the equivalent circuit and the impedances of each equivalent element is determined, leading to the second circuit impedance relationship. According to the types of multiple equivalent elements, the element impedance relationship between the impedance of each equivalent element and the corresponding parameter of the equivalent element can be determined. For example, the element impedance relationship for a resistor is that the impedance of the resistor equals its resistance value; the element impedance relationship for a capacitor is the relationship between the impedance of the capacitor and its capacitance value. Based on the first circuit impedance relationship, the second circuit impedance relationship, and the element impedance relationships of each element, the relationship between the real part of the impedance and the parameters of multiple equivalent elements, as well as the relationship between the imaginary part of the impedance and the parameters of multiple equivalent elements, can be obtained.

[0072] In this embodiment, the impedance parameters may further include phase and magnitude, and the circuit parameter relationships may further include phase relationships and magnitude relationships. After obtaining the impedance real part relationship between the real part of the impedance and the parameters of multiple equivalent elements, and the impedance imaginary part relationship between the imaginary part of the impedance and the parameters of multiple equivalent elements, based on the first circuit impedance relationship, the second circuit impedance relationship, and the element impedance relationship of each element, the phase relationship between the impedance and the parameters of multiple equivalent elements, and the magnitude relationship between the impedance and the parameters of multiple equivalent elements, can be obtained based on the impedance real part relationship and the impedance imaginary part relationship.

[0073] S43. Based on the impedance and / or phase test values ​​and the circuit parameter relationship, obtain the initial parameter values ​​of multiple equivalent elements in the initial equivalent circuit.

[0074] In this embodiment, the impedance test value may include the real part impedance test value and the imaginary part impedance test value. The initial parameter values ​​of multiple equivalent elements in the initial equivalent circuit can be calculated based on the real part impedance test value, the imaginary part impedance test value, and the real part impedance relation and the imaginary part impedance relation.

[0075] In this embodiment, the impedance test value may also include the magnitude test value. The initial parameter values ​​of multiple equivalent elements in the initial equivalent circuit can be obtained based on the magnitude test value, phase test value, phase relationship formula and magnitude relationship formula.

[0076] In one embodiment of this application, the impedance parameter includes the real part of the impedance and the imaginary part of the impedance, and the circuit parameter relationship includes the impedance real part relationship and the impedance imaginary part relationship. Step S42 includes:

[0077] S421. Based on the types and connection relationships of multiple equivalent elements, determine the first circuit impedance relationship between the impedance of the initial equivalent circuit and the real and imaginary parts of the impedance.

[0078] In this embodiment, according to Figure 2 It can be seen that the initial equivalent circuit is a two-port network. Based on the impedance and phase characteristics of the two-port network, the impedance of the initial equivalent circuit is determined to be a complex impedance including both the real and imaginary parts. Therefore, the first circuit impedance relationship of the initial equivalent circuit is as follows:

[0079] Z = R + jX,

[0080] Where Z is the impedance of the initial equivalent circuit, R is the real part of the impedance, X is the imaginary part of the impedance, and j is the imaginary unit.

[0081] S422. Based on the connection relationship of multiple equivalent elements, determine the second circuit impedance relationship between the impedance of the initial equivalent circuit and the impedance of multiple equivalent elements.

[0082] In this embodiment, based on the series and parallel connection relationships of multiple equivalent elements, the relationship between the total impedance of the equivalent circuit and the impedance of each equivalent element can be determined. This allows for the determination of a second circuit impedance relationship between the impedance of the initial equivalent circuit and the impedances of the multiple equivalent elements. Specifically, the second circuit impedance relationship is as follows:

[0083]

[0084] Where Z is the impedance of the initial equivalent circuit, Z R1 Z is the impedance of the first resistor. C1 Z is the impedance of the first capacitor. R2 Z is the impedance of the second resistor. C2 The impedance of the second capacitor is given.

[0085] S423. Based on the types of multiple equivalent elements, determine the element impedance relationship between the impedance of each equivalent element and the parameters of the corresponding equivalent element.

[0086] In this embodiment, the element impedance relationship of the first resistor is the impedance Z of the first resistor. R1 The impedance of the second resistor is equal to the resistance value R1 of the first resistor. The component impedance relationship of the second resistor is also known as the impedance Z. R2 The impedance relationship between the first capacitor and the second capacitor is equal to the resistance value R2 of the first resistor. The specific formulas for these relationships are as follows:

[0087]

[0088] Among them, Z C1Let be the impedance of the first capacitor, j be the imaginary unit, π be pi, f be the frequency, C1 be the capacitance of the first capacitor, and C2 be the capacitance of the second capacitor.

[0089] S424. Based on the first circuit impedance relationship, the second circuit impedance relationship, and the component impedance relationship, obtain the impedance real part relationship between the real part of the impedance and the parameters of multiple equivalent components, and the impedance imaginary part relationship between the imaginary part of the impedance and the parameters of multiple equivalent components.

[0090] Based on the first circuit impedance relationship, the second circuit impedance relationship, and the component impedance relationship of each element, the impedance real part relationship between the real part of the impedance and the parameters of multiple equivalent elements, and the impedance imaginary part relationship between the imaginary part of the impedance and the parameters of multiple equivalent elements can be obtained. As one implementation embodiment, in this application, the impedance real part relationship is specifically as follows:

[0091]

[0092] Where R is the real part of the impedance, π is pi, f is the frequency, C1 is the capacitance of the first capacitor, C2 is the capacitance of the second capacitor, R1 is the resistance of the first resistor, and R2 is the resistance of the second resistor.

[0093] The specific relationship of the imaginary part of impedance is as follows:

[0094]

[0095] Where X is the imaginary part of the impedance, π is pi, f is the frequency, C1 is the capacitance of the first capacitor, C2 is the capacitance of the second capacitor, R1 is the resistance of the first resistor, and R2 is the resistance of the second resistor.

[0096] As one implementation method, in this embodiment, the impedance test value includes the real part impedance test value and the imaginary part impedance test value. Based on the impedance and / or phase test values ​​and the circuit parameter relationship, the initial parameter values ​​of multiple equivalent elements in the initial equivalent circuit are obtained, including:

[0097] Based on the measured values ​​of the real part and imaginary part of the impedance, the relationship between the real part and imaginary part of the impedance, the initial parameter values ​​of multiple equivalent elements in the initial equivalent circuit are obtained.

[0098] In this embodiment, based on the number of equivalent elements, one or more sets (e.g., two sets if the number of equivalent elements is 4) of impedance real part test values ​​and impedance imaginary part test values ​​are substituted into the impedance real part relation and impedance imaginary part relation to obtain the initial parameter values ​​of multiple equivalent elements in the initial equivalent circuit. For example, by substituting two sets of impedance real part test values ​​and impedance imaginary part test values ​​into the impedance real part relation and impedance imaginary part relation, the resistance value of the first resistor, the resistance value of the second resistor, the capacitance value of the first capacitor, and the capacitance value of the second capacitor in the initial equivalent circuit can be calculated.

[0099] In one embodiment of this application, the impedance parameters further include phase and magnitude, and the circuit parameter relationships further include phase relationship and magnitude relationship. After step S424, the following is also included:

[0100] S425. Based on the real part and imaginary part of impedance, obtain the phase relationship between the phase and the parameters of multiple equivalent elements, and the magnitude relationship between the magnitude and the parameters of multiple equivalent elements.

[0101] In this embodiment, the phase relationship between the phase and the real and imaginary parts of the impedance is as follows:

[0102]

[0103] Where P is the phase, R is the real part of the impedance, and X is the imaginary part of the impedance. Substituting the relationships between the real and imaginary parts of the impedance into the phase relationships between the phase and the parameters of multiple equivalent elements, we can obtain the phase relationships between the phase and the parameters of multiple equivalent elements, as follows:

[0104]

[0105] Where P is the phase, π is the mathematical constant pi, f is the frequency, C1 is the capacitance of the first capacitor, C2 is the capacitance of the second capacitor, R1 is the resistance of the first resistor, and R2 is the resistance of the second resistor.

[0106] In this embodiment, the relationship between the magnitude and the magnitudes of the real and imaginary parts of the impedance is as follows:

[0107]

[0108] Where |Z| is the magnitude, R is the real part of the impedance, and X is the imaginary part of the impedance. Substituting the relationships between the real and imaginary parts of the impedance into the relationships between the magnitude and the magnitudes of the real and imaginary parts of the impedance, we can obtain the relationships between the magnitude and the parameters of multiple equivalent elements, as follows:

[0109]

[0110] Where |Z| is the magnitude, π is the mathematical constant pi, f is the frequency, C1 is the capacitance of the first capacitor, C2 is the capacitance of the second capacitor, R1 is the resistance of the first resistor, and R2 is the resistance of the second resistor.

[0111] As one implementation method, in this embodiment of the application, the impedance test value further includes the modulus test value. Based on the impedance and / or phase test values ​​and the circuit parameter relationship, the initial parameter values ​​of multiple equivalent elements in the initial equivalent circuit are obtained, including:

[0112] Based on the magnitude test value, phase test value, phase relationship formula, and magnitude relationship formula, the initial parameter values ​​of multiple equivalent elements in the initial equivalent circuit are obtained.

[0113] In this embodiment, based on the number of equivalent elements, one or more sets (e.g., two sets if the number of equivalent elements is 4) of modulus test values ​​and phase test values ​​are substituted into the phase relation and modulus relation to obtain the initial parameter values ​​of multiple equivalent elements in the initial equivalent circuit. For example, by substituting two sets of modulus test values ​​and phase test values ​​into the phase relation and modulus relation, the resistance value of the first resistor, the resistance value of the second resistor, the capacitance value of the first capacitor, and the capacitance value of the second capacitor in the initial equivalent circuit can be calculated.

[0114] As one implementation method, in this embodiment of the application, the initial parameter values ​​of multiple equivalent elements in the initial equivalent circuit are obtained based on impedance and / or phase test values ​​and circuit parameter relationships, including:

[0115] Based on the measured values ​​of the real part of impedance, the imaginary part of impedance, the phase, the magnitude, the impedance real part relation, the impedance imaginary part relation, the phase relation, and the magnitude relation, the initial parameter values ​​of multiple equivalent elements in the initial equivalent circuit are obtained.

[0116] In this embodiment, a set of impedance real part test values, impedance imaginary part test values, phase test values, and magnitude test values ​​can be substituted into the impedance real part relation, impedance imaginary part relation, phase relation, and magnitude relation, respectively, to calculate the initial parameter values ​​of multiple equivalent elements in the initial equivalent circuit. For example, the resistance value of the first resistor, the resistance value of the second resistor, the capacitance value of the first capacitor, and the capacitance value of the second capacitor in the initial equivalent circuit can be calculated.

[0117] As one implementation method, in this embodiment of the application, the preset parameter relationship is determined by the following method:

[0118] S11. Obtain the impedance and phase experimental test values ​​of the experimental physical equivalent circuit at a preset frequency. The experimental physical equivalent circuit is a circuit made based on the initial equivalent circuit of the experimental biological fluid.

[0119] In this embodiment, one or more experimental biological fluids with different impedance and phase characteristics can be selected for the experiment. A testing analyzer (such as an impedance analyzer) is used to test the experimental biological fluids at a preset frequency to obtain the impedance and phase test values. The impedance test value includes the real part test value R, the imaginary part test value X, and the magnitude test value |Z| of the impedance. The phase test value is P. The test values ​​obtained from testing three experimental biological fluid (such as blood) samples, namely samples 1 to 3, are shown in Table 1 below.

[0120] Experimental test values R (real part) X (imaginary part) |Z| value / Ω P value / ° Sample 1 9783.562 -470.116781 9794.8535 -2.7505 Sample 2 19319.77 -3363.53202 19610.42 -9.876 Sample 3 29650.15 -9493.23919 31132.96 -17.752

[0121] Based on the impedance and phase experimental values ​​of the experimental biological fluid, an initial equivalent circuit for the experimental biological fluid is established. This initial equivalent circuit includes the types, connections, and initial parameter values ​​of multiple equivalent components. Based on this initial equivalent circuit, the physical equivalent circuit is fabricated, thus establishing the experimental equivalent circuit. Figure 2 The circuit shown has equivalent element types and connection relationships. Substituting the test values ​​in Table 1 into the impedance real part relationship, impedance imaginary part relationship, phase relationship, and magnitude relationship respectively, the resistance values ​​of the first resistor R1, the second resistor R2, the capacitance values ​​of the first capacitor C1 and the second capacitor C2 in the initial equivalent circuit are calculated, as shown in Table 2 below:

[0122] Initial parameter values C1 / pF C2 / pF R1 / Ω R2 / Ω Sample 1 4.43 2.597 278600 10060 Sample 2 2.733 4.738 140700 20450 Sample 3 4.430 3.807 59770 34570

[0123] Due to limitations in resistance and capacitance values ​​in practical applications, the actual components used are selected from the nominal resistors and capacitors that are closest to the initial parameter values ​​of the equivalent components. The parameter values ​​of the components used to construct the experimental equivalent circuit are shown in Table 3 below:

[0124] Physical parameter values C1 / pF C2 / pF R1 / Ω R2 / Ω Sample 1 4.4 2.5 278640 10000 Sample 2 2.7 4.7 140000 20500 Sample 3 4.4 3.8 59700 34800

[0125] Then, a test analyzer (such as an impedance analyzer) is used to test the experimental equivalent circuit at a preset frequency to obtain the impedance and phase test values ​​of the experimental equivalent circuit. Specifically, the magnitude test values ​​of the impedance and the phase test values ​​are shown in Table 4 below:

[0126] Test value name Phase experimental test values Modulus experimental test value Sample 1 -3.063 9680.927 Sample 2 -11.5867 19468.75 Sample 3 -20.5763 30335.78

[0127] S12. Based on the initial parameter values ​​of multiple equivalent elements and the circuit parameter relationship of the initial equivalent circuit of the experimental biological fluid, the impedance and phase calculation values ​​are obtained.

[0128] In this embodiment, the initial parameter values ​​of multiple equivalent elements in the initial equivalent circuit of the experimental biological fluid are substituted into the modulus relationship between the modulus and the parameters of the multiple equivalent elements to calculate the modulus of the impedance. The initial parameter values ​​of multiple equivalent elements in the initial equivalent circuit of the experimental biological fluid are substituted into the phase relationship to calculate the phase, as shown in Table 5 below.

[0129] Calculated value name Phase calculation value Modulus calculation value Sample 1 -2.66965648 9743.127 Sample 2 -9.82388285 19669.19 Sample 3 -17.811507 31337.14

[0130] S13. Obtain the impedance and phase deviations based on the experimentally measured values ​​and the calculated values ​​of impedance and phase.

[0131] In this embodiment, the modulus deviation (such as the relative error of the modulus) can be obtained by calculating the modulus experimental test value and the modulus calculated value, and the phase deviation (such as the relative error of the phase) can be obtained by calculating the phase experimental test value and the phase calculated value, as shown in Table 6 below:

[0132] Error Name relative error of modulus Phase relative error Sample 1 -0.64％ 14.73％ Sample 2 -1.02％ 17.94％ Sample 3 -3.20％ 15.52％

[0133] As can be seen from the table above, the relative error of the modulus and the relative error of the P-value and phase are relatively large, with the phase relative error being more significant. The largest phase relative error among the three samples reaches 17.94%.

[0134] S14. Based on the impedance and phase deviation, adjust the initial parameter values ​​of the equivalent elements of the initial equivalent circuit of the experimental biological liquid until the absolute values ​​of the impedance and phase deviation are less than the preset absolute value of the deviation. Use the adjusted initial parameter values ​​as the physical parameter values ​​of the equivalent elements of the initial equivalent circuit of the experimental biological liquid.

[0135] In this embodiment, based on the relative error of the modulus and the relative error of the phase, the initial parameter values ​​of the equivalent elements of the initial equivalent circuit of the experimental biological fluid are adjusted. The initial parameter values ​​of a single equivalent element or multiple equivalent elements can be adjusted so that the absolute values ​​of the impedance deviation and the absolute values ​​of the phase deviation are both less than the preset absolute values ​​of the deviation (e.g., 5%). The parameter values ​​after adjustment for samples 1 to 3 are shown in Table 7 below:

[0136]

[0137]

[0138] The adjusted component parameter values ​​in Table 7 are then used as the adjusted physical parameter values ​​of the equivalent components in the initial equivalent circuit of the experimental biological fluid. Based on the adjusted physical parameter values, component types, and connection relationships, the adjusted experimental equivalent circuit can be fabricated. After testing, the adjusted phase experimental test values ​​and adjusted modulus experimental test values ​​are obtained, as shown in Table 8 below:

[0139] Adjusted test value name Phase experimental test values Modulus experimental test value Sample 1 -2.72 9747.202 Sample 2 -9.783 19633.051 Sample 3 -17.8268 31247.315

[0140] The adjusted relative error of the modulus can be obtained by calculating the adjusted experimental values ​​of the modulus in Table 8 and the calculated values ​​of the modulus in Table 5. The adjusted relative error of the phase can be obtained by calculating the adjusted experimental values ​​of the phase in Table 8 and the calculated values ​​of the phase in Table 5, as shown in Table 9 below:

[0141] Adjusted error name relative error of modulus Phase relative error Sample 1 0.04％ 1.91％ Sample 2 -0.18％ -0.42％ Sample 3 -0.29％ 0.09％

[0142] As can be seen from the table above, after testing the experimental equivalent circuit made by adjusting the parameter values ​​of the components, the relative error of the adjusted modulus and the relative error of the adjusted phase are significantly reduced, both less than the preset absolute value of 5%. This allows the experimental equivalent circuit made by adjusting the parameter values ​​of the components to be able to replace biological fluids such as blood samples or tissue fluids for testing within the accuracy range.

[0143] S15. Replace the experimental biological liquid with different impedances and phase characteristics, and repeat the above steps to obtain multiple sets of initial parameter values ​​and physical parameter values ​​with corresponding relationships. Establish a functional relationship based on the multiple sets of initial parameter values ​​and physical parameter values ​​with corresponding relationships, and use the functional relationship as the preset parameter relationship.

[0144] In this embodiment, various experimental biological solutions with different impedances and phase characteristics are used, and steps S11 to S14 are repeated to obtain multiple sets of corresponding initial parameter values ​​and physical parameter values. A functional relationship is established based on these multiple sets of corresponding initial parameter values ​​and physical parameter values, and this functional relationship is used as a preset parameter relationship. For example, if three experimental biological solution samples with different impedances and phase characteristics are selected, and steps S11 to S14 are repeated, the corresponding initial parameter values ​​and physical parameter values ​​of the second capacitor C2 are shown in Table 10 below:

[0145] C2's capacitance Sample 1 Sample 2 Sample 3 Initial parameter values 2.5 4.7 3.8 Physical parameter values 1.7 3.8 2.7

[0146] According to Table 10, the initial parameter value (X) and the actual parameter value (Y) after excluding the influence of factors such as parasitic capacitance have the following functional relationship:

[0147] Linear function: Y = 0.7621X - 0.039(R) 2 =0.927), Logarithmic function: Y = 3.0519ln(X) - 1.071(R) 2 =0.9254), quadratic function: Y = -0.326X 2 +1.0375X - 0.5696(R) 2 =0.9282), which can be a linear function and / or a logarithmic function and / or a quadratic function as a preset parametric relationship.

[0148] In this embodiment of the application, steps S11-S15 may be performed before step S2.

[0149] The embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other.

[0150] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for designing a physical equivalent circuit for a biological fluid, characterized in that, include: The biological fluid was tested at a preset frequency to obtain the impedance and phase test values ​​of the biological fluid. Based on the impedance and phase test values, an initial equivalent circuit of the biological fluid is established. The initial equivalent circuit includes the types, connection relationships, and initial parameter values ​​of multiple equivalent elements. Based on the initial parameter values ​​and the preset parameter relationship, the physical parameter values ​​of multiple equivalent elements of the initial equivalent circuit are obtained; Based on the physical parameter values, the types and connection relationships of multiple equivalent elements of the initial equivalent circuit, a physical equivalent circuit of the biological fluid is constructed. The initial equivalent circuit of the biological fluid is established based on the impedance and phase test values. This initial equivalent circuit includes the types, connection relationships, and initial parameter values ​​of multiple equivalent components, including: Based on the impedance and phase test values, an initial equivalent circuit of the biological fluid, including the types and connection relationships of multiple equivalent elements, is constructed. Based on the types and connection relationships of the multiple equivalent elements, the relationship between the impedance parameters of the initial equivalent circuit and the circuit parameters of the multiple equivalent elements is obtained; Based on the impedance and / or phase test values ​​and the circuit parameter relationship, the initial parameter values ​​of the multiple equivalent elements in the initial equivalent circuit are obtained. The preset parameter relationship is determined by the following method: The impedance and phase experimental test values ​​of the experimental physical equivalent circuit are obtained by testing at a preset frequency. The experimental physical equivalent circuit is a circuit made based on the initial equivalent circuit of the experimental biological fluid. Based on the initial parameter values ​​of multiple equivalent elements of the initial equivalent circuit of the experimental biological fluid and the circuit parameter relationship, the impedance and phase calculation values ​​are obtained. The impedance and phase deviations are obtained based on the experimentally measured impedance and phase values ​​and the calculated impedance and phase values. Based on the impedance and phase deviation, adjust the initial parameter values ​​of the equivalent elements of the initial equivalent circuit of the experimental biological fluid until the absolute values ​​of the impedance and phase deviation are less than the preset absolute value of the deviation. Then, use the adjusted initial parameter values ​​as the physical parameter values ​​of the equivalent elements of the initial equivalent circuit of the experimental biological fluid. By changing the experimental biological fluid with different impedances and phase characteristics, the above steps are repeated to obtain multiple sets of initial parameter values ​​and physical parameter values ​​with corresponding relationships. A functional relationship is established based on the multiple sets of initial parameter values ​​and physical parameter values ​​with corresponding relationships, and the functional relationship is used as the preset parameter relationship.

2. The method according to claim 1, characterized in that, The initial equivalent circuit includes a first resistor, a second resistor, a first capacitor, and a second capacitor, wherein: The first resistor and the first capacitor connected in series are connected in parallel with the second resistor. The second capacitor is connected in parallel with the second resistor.

3. The method according to claim 1 or 2, characterized in that, The impedance parameter includes a real part and an imaginary part of the impedance, and the circuit parameter relationship includes a relationship for the real part of the impedance and a relationship for the imaginary part of the impedance. The step of obtaining the impedance parameter relationship between the initial equivalent circuit and the circuit parameter relationship of the multiple equivalent elements based on their types and connections includes: Based on the types and connection relationships of the multiple equivalent elements, determine the first circuit impedance relationship between the impedance of the initial equivalent circuit and the real and imaginary parts of the impedance; Based on the connection relationship of the plurality of equivalent elements, a second circuit impedance relationship is determined between the impedance of the initial equivalent circuit and the impedance of the plurality of equivalent elements. Based on the types of the plurality of equivalent elements, determine the element impedance relationship between the impedance of each of the plurality of equivalent elements and the parameters of the corresponding equivalent element; Based on the first circuit impedance relationship, the second circuit impedance relationship, and the component impedance relationship, the impedance real part relationship between the real part of the impedance and the parameters of the multiple equivalent components, and the impedance imaginary part relationship between the imaginary part of the impedance and the parameters of the multiple equivalent components are obtained.

4. The method according to claim 3, characterized in that, The impedance test values ​​include the real part of the impedance test values ​​and the imaginary part of the impedance test values. The step of obtaining the initial parameter values ​​of multiple equivalent elements in the initial equivalent circuit based on the impedance and / or phase test values ​​and the circuit parameter relationship includes: Based on the measured values ​​of the real part of the impedance, the measured values ​​of the imaginary part of the impedance, the relationship between the real part of the impedance and the relationship between the imaginary part of the impedance, the initial parameter values ​​of the multiple equivalent elements in the initial equivalent circuit are obtained.

5. The method according to claim 3, characterized in that, The impedance parameters further include phase and magnitude, and the circuit parameter relationships further include phase relationships and magnitude relationships. After obtaining the impedance real part relationship between the real part of the impedance and the parameters of the plurality of equivalent elements, and the impedance imaginary part relationship between the imaginary part of the impedance and the parameters of the plurality of equivalent elements, based on the first circuit impedance relationship, the second circuit impedance relationship, and the element impedance relationship, the method further includes: Based on the real part of the impedance relationship and the imaginary part of the impedance relationship, the phase relationship between the phase and the parameters of the multiple equivalent elements, and the magnitude relationship between the magnitude and the parameters of the multiple equivalent elements are obtained.

6. The method according to claim 5, characterized in that, The impedance test value also includes the modulus test value. The process of obtaining the initial parameter values ​​of multiple equivalent elements in the initial equivalent circuit based on the impedance and / or phase test values ​​and the circuit parameter relationship includes: Based on the magnitude test value, the phase test value, the phase relation, and the magnitude relation, the initial parameter values ​​of the multiple equivalent elements in the initial equivalent circuit are obtained.

7. The method according to claim 5, characterized in that, The step of obtaining the initial parameter values ​​of multiple equivalent elements in the initial equivalent circuit based on the impedance and / or phase test values ​​and the circuit parameter relationship includes: Based on the measured values ​​of the real part of the impedance, the measured values ​​of the imaginary part of the impedance, the measured values ​​of the phase, the measured values ​​of the magnitude, the relationship between the real part of the impedance, the relationship between the imaginary part of the impedance, the relationship between the phase, and the relationship between the magnitude, the initial parameter values ​​of the multiple equivalent elements in the initial equivalent circuit are obtained.

8. The method according to claim 3, characterized in that, The specific relationship for the real part of the impedance is as follows: in, This is the real part of the impedance. Pi For frequency, This is the capacitance value of the first capacitor. This is the capacitance value of the second capacitor. This is the resistance value of the first resistor. This is the resistance value of the second resistor; The specific relationship of the imaginary part of the impedance is as follows: in, This is the imaginary part of the impedance. Pi For frequency, This is the capacitance value of the first capacitor. This is the capacitance value of the second capacitor. This is the resistance value of the first resistor. This is the resistance value of the second resistor.

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