A general method for eliminating electrical and magnetic interference in a measurement system

Abstract

The application discloses a new general method for eliminating electric and magnetic interference in measurement system. For electric measurement using differential amplifier, common mode signal is led out from differential amplifier and amplified as interference signal. After the amplified signal is sampled, it is used as interference template. The matching template component is searched in signal and then subtracted from the signal to eliminate interference and improve signal to noise ratio. For magnetic signal detection sensor using gradient coil structure, the center is grounded and two signal ends output mixed signal containing common mode component representing interference and measured signal. The common mode component is led out from differential amplifier as interference template to complete elimination of interference component in signal through the same template matching analysis and subtraction. The method for eliminating electromagnetic interference can be widely used in electric and magnetic signal measurement system.

Description

Technical Field

[0001] This application relates to the technical field of suppressing electrical and magnetic interference in the measurement of electrical and magnetic signals, and more specifically, to a general method for eliminating electrical and magnetic interference in a measurement system. Background Technology

[0002] The measurement and analysis of electrical and magnetic signals are essential components in scientific research and almost all applied fields. One of the most important indicators for evaluating the performance of an electromagnetic measurement system is the signal-to-noise ratio (SNR). Given a measurement signal, reducing noise is a key factor in improving the SNR. Generally, noise originates from two main sources: first, the noise of the signal source and the measurement circuit itself, especially the thermal noise from the random drift of electrons in the measurement circuit, which is related to ambient temperature; second, interference components generated by other external electrical and magnetic signal sources. The method described in this application aims to suppress interference components in the signal, also known as interference signals. These interference signals can be electrical components or electrical components induced in the measurement system by changes in the external magnetic field. In this discussion, noise and interference may be used interchangeably; unless otherwise stated, noise specifically refers to interference. Magnetic signals refer to signals whose magnetic induction amplitude varies with time, such as the magnetic resonance signals detected by an MRI scanner or the magnetic signals accompanying neural discharge activity measured by a magnetoencephalogram (MEG) scanner.

[0003] Typically, the textbook approach to handling electrical interference in electrical measurements involves using a dual-electrode system. The detected signal is then amplified by a preamplifier circuit consisting of a differential amplifier (or instrumentation amplifier) ​​with a high common-mode rejection ratio (CMRR). For example, electrocardiographs used clinically to measure electrocardiogram (ECG) signals commonly employ this input method. This is because the electrodes are typically placed closer to the signal source, allowing for the detection of the potential difference between the two electrodes. External interference, such as power frequency electromagnetic interference from ubiquitous power lines, originates from a location farther from the electrodes. This induces interference voltages of similar phase and amplitude on both electrodes, exhibiting a clear common-mode characteristic that is easily suppressed by a differential amplifier with high CMRR performance.

[0004] Nevertheless, common-mode interference still exists in the measured ECG signal. Therefore, standard ECG machines are always designed with a user-selectable 50Hz (or 60Hz, depending on the country of use) notch filter for further filtering.

[0005] Similar to the electrical measurements mentioned above, all magnetic signal measurement systems are inevitably susceptible to noise interference. In magnetic signal measurement, to suppress interference, a measurement probe with a gradient coil structure is usually used to detect the magnetic signal. The most common gradient coil is the figure-of-eight structure. Two circular coils of the same area and windings, placed close together in the same plane (planar gradient coil) or axially spaced (axial gradient coil), constitute a gradient antenna. The measured magnetic signal generates currents of the same magnitude but opposite directions in the two coils of the gradient coil, thereby canceling out common-mode interference. A typical application example of a planar figure-of-eight gradient antenna is the use of the Earth's magnetic field as a polarizing magnetic field to detect underwater oil spills in the Arctic region (L. Chavez et al., "Detecting Arctic oil spills with NMR: afeasibility study," Near Surface Geophysics 13(4), 409-416 (2015). Such an antenna system can sensitively detect weak geomagnetic magnetic resonance signals and effectively suppress environmental interference.

[0006] Clearly, the symmetry of a gradient antenna determines its ability to suppress common-mode magnetic interference. Common figure-eight antennas and their various variations exhibit axial symmetry in the plane in which the antenna lies. The same inventor in this application previously invented a centrally symmetric antenna for measuring quadrupole resonance signals (US Patent 11300644, Nuclear quadrupole resonance detection system and antenna), which is structurally easier to symmetric and has better common-mode interference suppression capabilities.

[0007] In some applications, to highlight the signal corresponding to one coil of a gradient antenna, an asymmetrical structure is often used, where the two coils have different diameters or different numbers of turns. The high-resolution magnetoencephalography (MEG) measurement device for young children invented by APEwing et al. (US20040002645A1_High-Resolution Magnetoencephalography System and Method) employs an asymmetrical axial gradient coil structure.

[0008] However, since gradient coils are not perfectly symmetrical in their fabrication, and considering the potential induction from the antenna-to-input amplifier connection in magnetic signal measurements, some common-mode interference will mix with the differential signal and enter the amplification process, thus reducing the signal-to-noise ratio. Therefore, in measurement circuits, appropriate filters are often designed based on the frequency characteristics of potential interference signals.

[0009] In multi-channel electrical signal measurement and multi-channel magnetic signal measurement, the orthogonal expansion decomposition of the signal space is used to distinguish between signals and interference. In signal processing and analysis, interference filtering is completed (US Patent 20140128002A1, Method and system for using orthogonal space projections to mitigate interference).

[0010] Furthermore, in the prior art, Chinese patent application CN109004911A (Charging and Discharging Device) discloses a differential amplifier with adjustable common-mode rejection and an amplifier circuit with improved common-mode rejection. This is achieved by estimating the common-mode voltage value of the input signal and adjusting the target common-mode voltage of the amplifier output using the estimated common-mode voltage value. Although this common-mode rejection method reduces common-mode interference in the mixed output signal to some extent and improves the signal-to-noise ratio of the output signal, it still cannot effectively reduce or completely eliminate common-mode interference signals mixed in the differential signal.

[0011] In summary, various existing anti-interference technologies, ranging from antenna structure and signal processing analysis to circuit design, have undergone extensive development and research. Currently, a solution is still lacking that can effectively eliminate common-mode interference in the output signal and improve the signal-to-noise ratio of the output signal during electromagnetic signal measurement. Summary of the Invention

[0012] The technical problem this application aims to solve is the interference problem inherent in existing electrical and magnetic signal measurement techniques. These problems arise either from electrode positions or trace connections in electrical measurements, or from the imperfect symmetry of gradient antennas in magnetic measurements, causing common-mode interference to mix with the original desired differential signal. This results in some common-mode interference always being mixed into the output signal, thus affecting the signal-to-noise ratio (SNR). This application provides a general method for eliminating electrical and magnetic interference in measurement systems. It can eliminate common-mode interference mixed in the differential signal, thereby obtaining the original desired signal with a high SNR, effectively solving the technical problem of unavoidable common-mode noise pollution in both electrical and magnetic signal measurements.

[0013] The technical solution adopted in this application to solve the above-mentioned technical problems is as follows:

[0014] A general method for eliminating electrical and magnetic interference in a measurement system is provided, the method comprising the following steps:

[0015] The central symmetrical point of the measurement gradient antenna is grounded, and the gradient antenna outputs a magnetic induction differential signal at both ends; or in electrical signal measurement, a differential signal is output through dual measurement electrodes.

[0016] The differential signal is output from the differential amplifier, and the common-mode signal is extracted.

[0017] The common-mode signal is amplified and sampled;

[0018] The sampled common-mode signal is used as a common-mode noise template. After the differential-mode signal output by the preamplifier is amplified and sampled again, the common-mode interference component corresponding to the common-mode noise template is identified; and

[0019] Remove the common-mode interference component from the differential-mode signal to obtain the original desired signal with a high signal-to-noise ratio after removing the common-mode interference component.

[0020] Further, the step of extracting the common-mode signal from the differential signal includes:

[0021] The preamplifier outputs a mixed signal; the expression for the mixed signal is: S mix (t)=S i (t)+S c (t)+N i (t), where S i (t) represents the desired differential signal component, S c (t) represents the mixture in the mixed signal S mix The common-mode interference component in (t), N i (t) represents inherent white noise;

[0022] The preamplifier outputs a total modulus output; the expression for the total modulus output is: S p (t)=S C (t)+N C (t), where S C (t) represents the common-mode interference component output from the preamplifier, N C (t) represents white noise mixed with the common-mode interference component;

[0023] Among them, the common-mode interference component S in the differential signal c (t) and the common-mode interference component S C (t) originating from the same interference source, the common-mode interference component S c (t) and the common-mode interference component S C (t) satisfies a linear relationship, the expression of which is:

[0024] S C (t)=k*S c (t);

[0025] Wherein, the coefficient k satisfies the following condition:

[0026] S i =Minimizing k→ Var{S mix (t)-k·S p (t)};The physical meaning of this mathematical optimization variance expression is that the total interference component S of the differential signal is c (t) is the common-mode component S C A scaling factor of (t); typically, due to S C (t)>S c (t), k is often less than 1;

[0027] The step of extracting the common-mode signal from the measurement signal further includes:

[0028] The coefficient k is determined based on the above conditions, and the common-mode interference component S in the signal is determined based on the coefficient k. c (t), where the common-mode interference component S C (t) serves as the common-mode noise template.

[0029] Furthermore, the step of removing the common-mode interference component from the differential-mode signal specifically includes:

[0030] Identify the common-mode interference component in the mixed signal that corresponds to the total total mode output, and remove the common-mode interference component from the mixed signal to obtain the original desired signal.

[0031] Furthermore, the method also includes:

[0032] The differential signal transmitted in the signal channel is filtered and amplified to convert the differential signal into a digital signal. The digital signal is then stored in a memory or output to an MCU so that the MCU can analyze and process the digital signal.

[0033] The common-mode signal transmitted in the common-mode channel is subjected to the same filtering and amplification process as the differential-mode channel, and the common-mode signal is converted into a digital signal. The digital signal is then stored in the memory or output to the MCU so that the MCU can analyze and process the digital signal.

[0034] The general method for eliminating electrical and magnetic interference in measurement systems proposed in this application has at least the following beneficial effects:

[0035] I. The general method for eliminating electrical and magnetic interference in the measurement system according to this application can use the common-mode signal output from the preamplifier as a common-mode noise template, identify the common-mode interference component corresponding to the common-mode noise template in the output mixed signal, and then remove the common-mode interference component in the mixed signal, thereby obtaining the original desired signal with high signal-to-noise ratio after eliminating common-mode interference. Therefore, it perfectly solves the technical problem in electrical and magnetic signal measurement where imperfect symmetry causes a part of the common-mode signal to become a differential signal and mix with the original desired signal, thus inevitably interfering with the original desired signal.

[0036] Second, the common-mode interference cancellation principle proposed in this application involves extracting the common-mode signal from the differential measurement of the magnetic signal, establishing a common-mode noise template using this signal, and identifying the corresponding common-mode interference component in the mixed signal using the template. This common-mode interference component is then removed from the mixed signal to obtain the original desired signal with a high signal-to-noise ratio. Therefore, only the central symmetrical point of the gradient coil needs to be grounded to provide a differential signal to the preamplifier. This eliminates the need for numerous additional electronic components, resulting in an extremely simple circuit structure, low cost, and excellent common-mode interference cancellation effect, making it highly valuable and promising for future applications. Attached Figure Description

[0037] The general method for eliminating electrical and magnetic interference in a measurement system according to this application will be described below with reference to the accompanying drawings and specific embodiments, wherein:

[0038] Figure 1 A flowchart of a general method for eliminating electrical and magnetic interference in a measurement system, provided as a preferred embodiment of this application;

[0039] Figure 2 for Figure 1 The flowchart shown is a detailed implementation of the step of extracting the common-mode signal from the differential signal, which is included in a general method for eliminating electrical and magnetic interference in a measurement system.

[0040] Figure 3 for Figure 1 The method shown includes optimized processing schemes for differential-mode and common-mode signals used to eliminate common-mode interference.

[0041] Figure 4 The circuit diagram of a first common-mode interference cancellation circuit provided in a preferred embodiment of this application is that a common-mode signal representing interference is output in a conventional differential amplifier;

[0042] Figure 5 The circuit diagram of a second common-mode interference cancellation circuit provided in a preferred embodiment of this application is designed for suppressing interference when measuring magnetic signals using a gradient antenna. Detailed Implementation

[0043] To make the objectives, technical solutions, and technical effects of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described in this specification are merely for explaining this application and are not intended to limit it.

[0044] To address the technical challenge in existing technologies where, in electrical and magnetic signal measurements, the imperfect symmetry of the measurement input circuit causes a portion of the common-mode signal to become a differential signal and mix with the original desired signal, inevitably interfering with the original desired signal, the innovation of this application lies in:

[0045] I. Based on the fact that the mixed signal transmitted in the signal channel and the common-mode signal representing interference transmitted in the common-mode channel both originate from the same noise source and have a specific linear relationship (that is, the difference in waveform characteristics between the two common-mode signals lies in their different amplitudes), the common-mode signal output from the preamplifier PreAMP is used as the noise template of the interference. The common-mode interference component corresponding to the common-mode noise template is identified in the mixed signal, and the common-mode interference component is removed from the mixed signal, thereby obtaining the original desired signal with a high signal-to-noise ratio after eliminating common-mode interference.

[0046] Second, the common-mode interference cancellation principle proposed in this application involves extracting the common-mode signal from the differential measurement of the magnetic signal, establishing a common-mode interference noise template, and using this template to identify the corresponding common-mode interference component in the mixed signal. Then, the common-mode interference component is removed from the mixed signal to obtain the original desired signal with a high signal-to-noise ratio. Therefore, only the central symmetrical point of the gradient coil needs to be grounded to provide a differential signal to the preamplifier and output a common-mode signal from it. This eliminates the need for a large number of additional electronic components, making the common-mode interference cancellation circuit of this application extremely simple in structure, low in cost, and with excellent common-mode interference cancellation effect.

[0047] The general method for eliminating electrical and magnetic interference in a measurement system according to this application is described in detail below with reference to the accompanying drawings and specific embodiments:

[0048] like Figure 1 As shown, since gradient coils cannot be perfectly symmetrical, in order to overcome the technical challenge of common-mode interference that is unavoidable in magnetic signal measurement, this application proposes a general method for eliminating electrical and magnetic interference in measurement systems. This method specifically includes the following steps:

[0049] In step S100, the central symmetrical point of the measurement gradient antenna is grounded, and the magnetic induction differential signal is output from both ends of the antenna; or in electrical signal measurement, the differential signal is output through dual measurement electrodes.

[0050] Step S200: Output the differential signal from the differential amplifier and extract the common-mode signal from the differential signal;

[0051] Step S300: The common-mode signal is amplified, filtered, and sampled in the same way as the differential signal;

[0052] Step S400: Using the sampled common-mode signal as an interference noise template, after amplifying and sampling the differential-mode signal output by the preamplifier PreAMP, the common-mode interference component corresponding to the interference noise template is identified; and

[0053] Step S500: Remove the common-mode interference component from the differential-mode signal to obtain the original desired signal with a high signal-to-noise ratio after eliminating the common-mode interference component.

[0054] like Figure 2 As shown, in a preferred embodiment, step S200 specifically includes:

[0055] Step S201: Output the mixed signal S through the preamplifier PreAMP. mix (t); the mixed signal S mix The expression for S(t) is: mix (t)=S i (t)+S c (t)+N i (t)(i.e., Formula 1).

[0056] Among them, S i (t) represents the desired differential signal component, S c (t) represents the mixture in the mixed signal S mix The common-mode interference component in (t), N i (t) represents inherent white noise;

[0057] Step S202, the total modulus output S from the preamplifier PreAMP is... p (t); The total modulus output S p The expression for S(t) is: p (t)=S C (t)+N C (t) (i.e., Formula 2). Where, S C (t) represents the common-mode interference component output from the preamplifier PreAMP, N C (t) represents the common-mode interference component S C (t) Mixed white noise.

[0058] Among them, the common-mode interference component S in the differential signal c(t) and the common-mode interference component S from the output of the preamplifier PreAMP C (t) comes from the same noise source, and the common-mode interference component S c (t) and the common-mode interference component S C (t) satisfies a linear relationship, the expression of which is:

[0059] S C (t)=k·S c (t)(i.e., Formula 3).

[0060] From the above equation, it can be seen that the common-mode interference component S c (t) and the common-mode interference component S C (t) represents a common-mode signal from the same interference source but with different amplitudes.

[0061] Based on formulas 1, 2, and 3 above, the following formula can be derived:

[0062] S mix (t)=S i (t)+k·S p (t)+N(t)=S i (t)+k·S C (t)+k·N C (t)

[0063] +N i (t)(i.e., Formula 4).

[0064] Since the common-mode interference in the interference source is uncorrelated with the desired signal, and generally speaking, the common-mode interference is orthogonal to the differential signal, therefore, in this application, the coefficient k can be obtained from the following mathematical optimization of the mixed signal S. mix (t) and the common-mode signal S proportional to k p The standard deviation of the difference (t) is used to obtain the result:

[0065] S i =Minimizing k→ Var{S mix (t)-k·S p (t)} (i.e., Formula 5);

[0066] That is, the mixed signal S mix (t) and the total modulus output S p The variance of the difference (t) multiplied by the coefficient k is minimized.

[0067] The physical meaning of this mathematically optimized variance expression (i.e., Equation 5) is that the common-mode interference component S in the differential signal... c (t) is the total mode disturbance S. CA scaling factor of (t). Typically, due to S... C (t)>S c (t), where the coefficient k is often less than 1. The k value obtained under the conditions of Formula 5 minimizes the common-mode component in the obtained signal, that is, it filters out common-mode interference.

[0068] In this application, step S200 above further includes:

[0069] Step S203: Determine the value of coefficient k based on mathematical optimization of the standard deviation, and determine the common-mode interference component S in the signal based on the value of coefficient k. c (t). Wherein, the common-mode interference component S C (t) serves as the template for interference noise.

[0070] In a preferred embodiment, step S500 specifically includes:

[0071] Identify mixed signal S mix The total modulus output S in (t) p (t) corresponds to the common-mode interference component S c (t), and remove the mixed signal S mix The common-mode interference component S in (t) c (t), thus obtaining the original desired signal.

[0072] like Figure 3 As shown, in a preferred embodiment, the above-described method for eliminating common-mode interference further includes:

[0073] Step S600: Before converting the differential-mode signal and the common-mode signal into digital signals, the differential-mode signal and the common-mode signal are amplified respectively.

[0074] In a preferred embodiment, the method for eliminating common-mode interference described above further includes:

[0075] Step S700: The differential signal transmitted in the signal channel is filtered and amplified to convert the differential signal into a digital signal. The digital signal is then stored in a memory or output to the MCU so that the MCU can analyze and process the digital signal.

[0076] The common-mode signal transmitted in the common-mode channel is subjected to the same filtering and amplification process as the differential-mode channel, and the common-mode signal is converted into a digital signal. The digital signal is then stored in the memory or output to the MCU so that the MCU can analyze and process the digital signal.

[0077] In this application, the differential signal refers to a signal from the dual measurement electrodes or a signal from the gradient antenna, wherein the central symmetrical point of the gradient antenna is grounded.

[0078] In summary, the general method for eliminating electrical and magnetic interference in a measurement system proposed in this application can output a mixed signal and a common-mode signal through a preamplifier (PreAMP). The common-mode signal output by the PreAMP is used as an interference noise template. By using interference noise template matching, the common-mode interference component corresponding to the interference noise template is identified in the mixed signal, and then removed from the mixed signal. This results in a high signal-to-noise ratio original desired signal with eliminated common-mode interference. Therefore, applying the method for eliminating common-mode interference proposed in this application can effectively solve the technical problem in electrical and magnetic signal measurements where imperfections cause some common-mode signals to become differential signals and mix with the original desired signal, inevitably interfering with the original desired signal.

[0079] Corresponding to the general methods described above for eliminating electrical and magnetic interference in measurement systems, such as Figure 4 As shown, this application also discloses a circuit implementation for outputting a common-mode signal corresponding to interference from a conventional differential amplifier.

[0080] like Figure 5 As shown, this application also discloses a common-mode interference cancellation circuit for eliminating magnetic interference in a magnetic signal measurement system. The electronic switch 114 isolates the connection between the excitation circuit (not shown) and the measurement circuit when the measuring device is used for excitation-measurement, such as magnetic resonance or quadrupole resonance signal measurement.

[0081] In summary, the improvements of this application compared to the prior art are reflected in at least the following aspects:

[0082] I. The method and apparatus for eliminating common-mode interference according to this application can use the common-mode signal output from the preamplifier as an interference noise template, identify the common-mode interference component corresponding to the common-mode noise template in the output mixed signal, and then remove the common-mode interference component in the mixed signal, thereby obtaining the original desired signal with high signal-to-noise ratio after eliminating common-mode interference. Therefore, it perfectly solves the technical problem in the measurement of electrical and magnetic signals that, due to imperfect symmetry, a part of the common-mode signal becomes a differential signal and mixes with the original desired signal, thus inevitably causing interference to the original desired signal.

[0083] Second, the common-mode interference cancellation principle proposed in this application involves extracting the common-mode signal from the differential measurement of the magnetic signal, using this common-mode signal to establish an interference noise template, and then using this common-mode noise template to identify the corresponding common-mode interference component in the mixed signal. This common-mode interference component is then removed from the mixed signal, thereby obtaining the original desired signal with a high signal-to-noise ratio. Therefore, only the central symmetrical point of the gradient coil needs to be grounded to provide a differential signal to the preamplifier, without the need for a large number of additional electronic components. This makes the common-mode interference cancellation circuit of this application extremely simple in structure, low in cost, and with good common-mode interference cancellation effect, possessing high application value and broad prospects.

[0084] It should be noted that the interfering template is subjected to white noise N C The influence of (t) can create a possible source of interference suppression error.

[0085] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many modifications based on the teachings of this application without departing from the spirit and scope of the claims, and all of these modifications are within the protection scope of this application. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on this application.

Claims

1. A general method for eliminating electrical and magnetic interference in a measurement system, characterized in that, Includes the following steps: In magnetic measurements, the central symmetrical point of the measuring gradient antenna is grounded, and the gradient antenna outputs a magnetic induction differential signal at both ends; or in electrical signal measurements, a differential signal is output through dual measuring electrodes. The differential signal is output from the differential amplifier, and the common-mode signal from the differential signal is extracted. The common-mode signal is amplified, filtered, and sampled. Based on the fact that the mixed signal transmitted in the signal channel and the common-mode signal representing interference transmitted in the common-mode channel both come from the same noise source and have a linear relationship, the sampled common-mode signal is used as an interference noise template, and the common-mode interference component corresponding to the interference noise template is identified in the differential-mode signal output by the preamplifier (PreAMP). as well as Remove the common-mode interference component from the differential-mode signal to obtain the original desired signal with a high signal-to-noise ratio after removing the common-mode interference component.

2. The general method for eliminating electrical and magnetic interference in a measurement system according to claim 1, characterized in that, The step of extracting the common-mode signal from the differential signal includes: The mixed signal S is output through the preamplifier (PreAMP). mix (t); the mixed signal S mix The expression for (t) is: S mix (t) = S i (t) + S c (t) + N i (t), where S i (t) represents the desired differential signal component, S c (t) represents the mixture in the mixed signal S mix The common-mode interference component in (t), N i (t) represents inherent white noise; The total modulus output S is obtained through the preamplifier (PreAMP). p (t); the total modulus output S p The expression for (t) is: S p (t) = S C (t) + N C (t), where S C (t) represents the common-mode interference component output from the preamplifier (PreAMP), N C (t) represents the common-mode interference component S. C (t) Mixed white noise; Wherein, the common-mode interference component S in the differential signal c (t) and the common-mode interference component S C (t) originating from the same interference source, the common-mode interference component S c (t) and the common-mode interference component S C (t) satisfies a linear relationship, the expression of which is: S c (t)= k·S C (t); Wherein, the coefficient k satisfies the following condition: S i =Minimizing k→ Var{S mix (t)-k·S p (t)};where, the mathematically optimized variance expression S i =Minimizing k→ Var{S mix (t)-k·S p The physical meaning of (t)} is that the common-mode interference component S in the differential signal is... c (t) is the common-mode interference component S C A scaling factor of (t); due to S C (t)>S c (t), k is usually less than 1; The step of extracting the common-mode signal from the differential signal further includes: The coefficient k is determined based on the above conditions, and the common-mode interference component S in the signal is determined based on the coefficient k. c (t), where the common-mode interference component S C (t) serves as the interference noise template.

3. The general method for eliminating electrical and magnetic interference in a measurement system according to claim 2, characterized in that, The step of removing the common-mode interference component from the differential-mode signal specifically includes: Identify the mixed signal S mix (t) and the total modulus output S p (t) corresponds to the common-mode interference component S c (t), and remove the mixed signal S mix The common-mode interference component S in (t) c (t) yields the original desired signal.

4. The general method for eliminating electrical and magnetic interference in a measurement system according to claim 1, characterized in that, The method further includes: The differential signal transmitted in the signal channel is filtered and amplified to convert the differential signal into a digital signal. The digital signal is then stored in a memory or output to an MCU so that the MCU can analyze and process the digital signal. The common-mode signal transmitted in the common-mode channel is subjected to the same filtering and amplification process as the differential-mode signal, converting the common-mode signal into a digital signal. The digital signal is then stored in the memory or output to the MCU for analysis and processing by the MCU.

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