Electromagnetic environment control method for performance detection of electrophysiological acquisition medical instrument

Abstract

This invention discloses an electromagnetic environment control method for performance testing of electrophysiological acquisition medical devices, belonging to the field of medical device testing technology. The method includes: S1, conducting an interference intensity scanning experiment on a pair of electromagnetically sensitive performance parameters in a microwave anechoic chamber, and performing quantitative electromagnetic interference modeling to obtain the relationship between interference field strength and performance parameter degradation increment; S2, fabricating a shield and testing its shielding effectiveness in a microwave anechoic chamber through a quantitative interference experiment, where the shielding effectiveness against electromagnetic interference is defined as its attenuation factor against the interference field strength; S3, testing the electromagnetically sensitive performance parameters in a testing environment that does not meet electromagnetic shielding requirements, using multiple shields that have completed quantitative shielding performance testing and an external interference electromagnetic field strength detection device to predict shielding effectiveness. This invention lowers the threshold for medical device testing and ensures testing efficiency and accuracy.

Description

Technical Field

[0001] This invention relates to the field of medical device testing technology, and in particular to an electromagnetic environment control method for performance testing of electrophysiological acquisition medical devices. Background Technology

[0002] In the field of medical device research and development and testing, electrophysiological (represented by electrocardiogram, electroencephalogram, and electromyography) acquisition equipment is a crucial and high-volume category of equipment, and the mandatory testing standards for it are constantly evolving. According to the standards, medical devices must undergo registration testing of all safety and performance indicators led by qualified testing institutions at the end of the research and development phase. Each product must also undergo factory testing of these parameters before leaving the factory, making it a vital part of a medical device company's quality management system. However, with the evolution of standards, the introduction of numerous performance indicators requiring precise quantitative testing presents challenges not only to testing institutions but also to manufacturers, especially for performance limit parameter testing under weak signal simulation conditions, where the test results are extremely sensitive to the electromagnetic environment of the testing site. Testing institutions generally possess the measurement capabilities of microwave anechoic chambers and electromagnetic shielding rooms, but due to the significant initial investment required, most manufacturing and R&D companies lack such stringent testing conditions. This has led to companies incurring substantial additional costs for batch outsourcing testing after the introduction of new standards in recent years. Furthermore, even for qualified testing institutions, the shielding conditions (spatial conditions) and the electromagnetic environment (temporal conditions) during specific tests vary. Real-time interference and background noise at the testing site cannot be strictly traced. Under these conditions, the obtained evaluation results are unstable and have low reliability. Therefore, a comprehensive solution is needed to lower the testing threshold and improve the stability and traceability of test results in the detection of precise electrophysiological performance parameters.

[0003] Taking the national standard GB9706.226-2021, "Basic Safety and Performance Requirements for Electroencephalogram (EEG) Machines," as an example, it specifies five categories of performance parameters to meet the needs of EEG acquisition and clinical diagnosis. Testing these parameters requires generating test signals at the amplitude level (μV level) of the EEG. To maximize the simulation of the actual effect when using the diagnostic equipment, the standard stipulates that all parameters must be tested with a patient cable connected. From the standard's testing methods, it tests the device's ability to quantify EEG signals and resist electromagnetic interference to a certain extent. However, because the target signal is very weak, and the standard mandates lead-line testing, its resistance, equivalent inductance, and distributed capacitance cannot be ignored. The presence of these parameters will exponentially increase the coupling of electromagnetic environmental noise into the acquisition device. If spatial electromagnetic interference reaches a certain level, the interference coupling will directly cause the performance parameters read by the testing system built according to the standard to exceed the specified limits, making it impossible to release the device for testing. The reason for this problem is the lack of a substantial solution for measuring and controlling spatial electromagnetic interference at the testing site.

[0004] Therefore, the key technical problem that this invention focuses on solving is to correct the detection results to a state without electromagnetic interference in an environment where it is practically impossible to completely shield electromagnetic interference, and to meet the mandatory standards for medical devices through certain detection methods, after rigorous verification. Summary of the Invention

[0005] The purpose of this invention is to provide an electromagnetic environment control method for performance testing of electrophysiological acquisition medical devices. By using a quantitative shielding room and electromagnetic environment monitoring equipment, the method enables the prediction of electromagnetically sensitive performance parameters in an environment with high shielding effectiveness.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] An electromagnetic environment control method for performance testing of electrophysiological acquisition medical devices, comprising:

[0008] S1. In a microwave anechoic chamber, an interference intensity scanning experiment is conducted on a certain performance parameter P1 that is sensitive to electromagnetic interference. A quantitative electromagnetic interference model is then performed on the performance parameter P1 to obtain the interference field strength E. i Relationship with the degradation increment ΔD of performance parameters:

[0009] D open =D ideal +ΔD=D ideal +f P1 (E i )

[0010] S2. Based on theoretical calculations and electromagnetic field simulations, a shielding body is fabricated, and its shielding effectiveness is tested in a microwave anechoic chamber through quantitative interference experiments. This test is used as the intrinsic parameter of the shielding body. Let the shielding effectiveness of the shielding body against electromagnetic interference be its response to interference field strength E. i Attenuation factor A c When there are multiple shielding elements, the measured attenuation factors are A. c1 A c2 ...A cn ;

[0011] S3. In a testing environment that does not meet electromagnetic shielding requirements, when testing performance parameters that are sensitive to electromagnetic interference, two or more shielding bodies that have completed quantitative shielding effectiveness testing are used, or an external interference electromagnetic field strength testing device and a shielding body are used, and the interference field strength at the performance parameter testing site is measured in real time to complete the prediction of arbitrary shielding effectiveness.

[0012] Furthermore, in step S3, two or more shielding bodies that have completed quantitative shielding performance testing are used to predict arbitrary shielding effectiveness, specifically including:

[0013] In an open electromagnetic environment, the target performance parameters are tested according to the testing standards, and their value is obtained as D. open ;

[0014] The equipment under test is placed inside a shielded enclosure whose shielding effectiveness has been precisely calibrated. The target performance parameters are then tested according to the testing standards, and the value is determined to be D. s1 ;

[0015] The equipment under test is then placed inside another shielded enclosure whose shielding effectiveness has been precisely calibrated. The target performance parameters are then tested according to the testing standards, and the value is determined to be D. s2 ;

[0016] If there are multiple shielding elements, continue measuring the performance parameter value D for each shielding element. sn ;

[0017] Let the desired performance index value under the ideal electromagnetic environment be set as D. ideal Then there is

[0018] D open =D ideal +ΔD=D ideal +f P1 (E i )

[0019]

[0020]

[0021]

[0022] Wherein, parameter D ideal and E i The value is obtained by the least squares method, yielding the calculated predicted value of this performance parameter under ideal electromagnetic conditions.

[0023] pass Introducing Arbitrary Shielding Effectiveness A cn Calculated and predicted values ​​of performance parameters under shielding effect.

[0024] Furthermore, in step S3, an external interference electromagnetic field strength detection device is used to measure the interference field strength at the testing site in real time, thereby predicting the shielding effectiveness of any object. Specifically, this includes:

[0025]

[0026] Among them, E i For the parameters obtained using the least squares method, A cn It is the pre-measured shielding effectiveness value, D sn The value D is from the measurement of this shielding structure. ideal The least squares method is used to obtain the result.

[0027] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects: The electromagnetic environment control method for performance testing of electrophysiological acquisition medical devices provided by the present invention, without relying on a relatively expensive dedicated electromagnetic shielding testing environment, utilizes a low-cost quantitative shielding body to calculate the test results after shielding, thereby enabling the prediction of the final performance parameters of electromagnetically sensitive performance parameters measured in an environment with high shielding effectiveness.

[0028] This invention requires only two or more shielding bodies that have undergone shielding effectiveness calibration to calculate the performance value of any shielding effectiveness testing environment, resulting in low cost. Alternatively, by combining real-time quantitative monitoring data of the spatial electromagnetic environment provided by calibrated instruments, a single measurement within the quantitatively effective shielding body is sufficient to calculate the performance value of any shielding effectiveness testing environment, balancing testing efficiency and data accuracy.

[0029] This invention avoids the large investment required to build high-efficiency electromagnetic shielding rooms, significantly reducing the hardware barriers to testing such medical devices and facilitating the construction of automated testing systems. By introducing quantitative shielding rooms and electromagnetic environment monitoring equipment, a metrology chain can be established within enterprises, allowing most of the precise performance parameter tests that previously relied on testing institutions to be handled independently by this invention. To ensure the rigor of standard implementation, prototype systems that have undergone formal testing by testing institutions can also undergo cross-validation of their final performance parameter results within this invention. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a flowchart of the electromagnetic environment control method for performance testing of electrophysiological acquisition medical devices according to the present invention. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] The purpose of this invention is to provide an electromagnetic environment control method for performance testing of electrophysiological acquisition medical devices. By using a quantitative shielding room and electromagnetic environment monitoring equipment, the method enables the prediction of electromagnetically sensitive performance parameters under a highly shielded environment.

[0034] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] Example 1

[0036] like Figure 1 As shown in the embodiment of the present invention, the electromagnetic environment control method for performance testing of electrophysiological acquisition medical devices includes:

[0037] S1. In a microwave anechoic chamber, an interference intensity scanning experiment is conducted on a certain performance parameter P1 that is sensitive to electromagnetic interference. A quantitative electromagnetic interference model is then performed on the performance parameter P1 to obtain the interference field strength E. i The relationship between the performance parameter degradation increment ΔD and the formula (generally determined by polynomial least squares fitting):

[0038] D open =D ideal +ΔD=D ideal +f P1 (E i )

[0039] When there are multiple performance parameters P that are sensitive to electromagnetic interference, quantitative modeling is required for each parameter.

[0040] S2. Under the guidance of theoretical calculations and electromagnetic field simulations, a shielding body is fabricated, and its shielding effectiveness is tested in a microwave anechoic chamber through quantitative interference experiments. This test is used as the intrinsic parameter of the shielding body. Let the shielding effectiveness of the shielding body against electromagnetic interference be its response to interference field strength E. i Attenuation factor A c When there are multiple shielding elements, the measured attenuation factors are A. c1 A c2 ...A cn ;

[0041] S3. In a testing environment that does not meet electromagnetic shielding requirements, when testing performance parameters that are sensitive to electromagnetic interference, two or more shielding bodies that have completed quantitative shielding effectiveness testing are used, or an external interference electromagnetic field strength testing device and a shielding body are used, and the interference field strength at the performance parameter testing site is measured in real time to complete the prediction of arbitrary shielding effectiveness.

[0042] Example 2

[0043] Based on Example 1, this example provides a method for calculating and predicting arbitrary shielding effectiveness when testing specific electromagnetic interference-sensitive performance parameters in a testing environment that does not meet electromagnetic shielding requirements (factory production lines or testing points without shielding rooms and microwave anechoic chambers)—using two or more shielding bodies that have completed quantitative shielding performance tests:

[0044] In an open electromagnetic environment, the target performance parameters are tested according to the testing standards, and their value is obtained as D. open ;

[0045] The equipment under test is placed inside a shielded enclosure whose shielding effectiveness has been precisely calibrated. The target performance parameters are then tested according to the testing standards, and the value is determined to be D. s1 ;

[0046] The equipment under test is then placed inside another shielded enclosure whose shielding effectiveness has been precisely calibrated. The target performance parameters are then tested according to the testing standards, and the value is determined to be D. s2 ;

[0047] If there are multiple shielding elements, continue measuring the performance parameter value D for each shielding element. sn ;

[0048] The interference field strength in an open electromagnetic environment can be approximated as E. i It remains constant across multiple measurements over a short period of time.

[0049] The performance index value to be determined under the ideal electromagnetic environment (no interference) is set as D. ideal Then there is

[0050] D open =D ideal +ΔD=D ideal +f P1 (E i )

[0051] Since measurements were taken two or more times within the shield, two or more additional equations can then be derived:

[0052]

[0053]

[0054]

[0055] In this equation, the only unknown is the parameter D. ideal and E i Since the number of equations is greater than the number of unknowns, the parameter D can be obtained using the least squares method. ideal and E i That is, the calculated and predicted value of this performance index under ideal electromagnetic conditions was derived, and then through... Introducing Arbitrary Shielding Effectiveness A cn Calculated and predicted values ​​of performance parameters under shielding effect.

[0056] In this embodiment, the more measurements are performed, the closer the calculated predicted value of the performance parameters will be to the actual measured value of the microwave anechoic chamber.

[0057] Example 3

[0058] Based on Examples 1-2, this example provides a method for calculating and predicting arbitrary shielding effectiveness when testing specific electromagnetic interference-sensitive performance parameters in testing environments that do not meet electromagnetic shielding requirements (factory production lines or testing points without shielding rooms and microwave anechoic chambers). This method involves using an external interference electromagnetic field strength detection device to measure the interference field strength at the performance parameter testing site in real time, and employing a shielding body.

[0059] Because of the introduction of interference electromagnetic field strength detection equipment, the equations can be directly derived.

[0060]

[0061] Among them, E i The parameters obtained using the least squares method are known conditions; A cn It is the pre-measured shielding effectiveness value, D sn The value D is from the measurement of this shielding structure. ideal It can be directly calculated, and at the same time, any shielding effectiveness A can be derived. cn Calculated and predicted values ​​of performance parameters under the shielding effect.

[0062] In summary, the electromagnetic environment control method for performance testing of electrophysiological acquisition medical devices provided by this invention constructs a locally shielded testing environment through a shielded body with precisely quantified shielding effectiveness. Process parameters are calculated and corrected, ultimately enabling the prediction of the performance parameters measured in an electromagnetically shielded testing environment with a preset shielding effectiveness. All standard-specified performance parameters are tested in an open environment and one or more quantitatively shielded environments. Optionally, the quantitative analysis of external interference in the testing environment can be combined with a quantitative function of electromagnetic interference attenuation to calculate and fit the measured values ​​of performance parameters sensitive to electromagnetic interference. Furthermore, the results of multi-point fitting curves can be used to calculate the performance parameter values ​​measured in a shielded room with any shielding effectiveness (or meeting the standard noise floor limit). This solves the problem in current factory inspections of electrophysiological acquisition medical devices where the performance testing of weak analog signal acquisition is significantly affected by complex on-site electromagnetic environments. Simultaneously, this invention effectively lowers the testing threshold for electromagnetic shielding in weak signal detection, eliminating the need for a laboratory-grade electromagnetic shielding room; only a simply designed enclosure is required, and quantitative measurement of shielding effectiveness can be performed in a laboratory environment.

[0063] To further improve the accuracy of calculation and prediction, this invention can conduct shielding environment tests with different shielding effectiveness, and use the least squares fitting of multi-point curves under overdetermined conditions to further reduce the impact of random errors in the detection. In addition, this invention can also monitor the electromagnetic interference intensity in the open environment in real time through the equipment, and combine it with a quantitative performance test inside the shielding body to directly and quantitatively calculate and predict the performance test results under ideal shielding test conditions.

[0064] The remaining technical features in this embodiment can be flexibly selected by those skilled in the art to meet different specific practical needs. However, it is obvious to those skilled in the art that these specific details are not necessary to implement the present invention. In other instances, to avoid obscuring the present invention, well-known components, structures, or parts are not specifically described, and all are within the scope of technical protection defined by the claims of the present invention.

[0065] Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of this invention should be within the protection scope of the appended claims. In the above description, numerous specific details have been set forth to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other instances, to avoid obscuring the invention, well-known techniques, such as specific construction details, operating conditions, and other technical conditions, have not been specifically described.

[0066] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for controlling the electromagnetic environment for performance testing of electrophysiological acquisition medical devices, characterized in that, include: S1, in a microwave darkroom, for a certain pair of electromagnetic interference sensitive performance parameters P1, interference intensity scanning experiment is carried out, the performance parameters P1 are quantitatively modeled by electromagnetic interference, and the interference field strength E i The relationship between the performance parameter degradation increment AD and the performance parameter degradation increment AD D open =D ideal +ΔD=D ideal +f P1 (E i ) S2. Based on theoretical calculations and electromagnetic field simulations, a shielding body was fabricated, and its shielding effectiveness was tested in a microwave anechoic chamber through quantitative interference experiments to obtain the intrinsic parameters of the shielding body; let the shielding effectiveness of the shielding body against electromagnetic interference be its response to interference field strength E. i Attenuation factor A c When there are multiple shielding elements, the measured attenuation factors are A. c1 A c2 ...A cn ; S3. In a testing environment that does not meet electromagnetic shielding requirements, when testing performance parameters that are sensitive to electromagnetic interference, two or more shielding bodies that have completed quantitative shielding effectiveness testing are used, or an external interference electromagnetic field strength testing device and a shielding body are used, and the interference field strength at the performance parameter testing site is measured in real time to complete the prediction of arbitrary shielding effectiveness.

2. The electromagnetic environment control method for performance testing of electrophysiological acquisition medical devices according to claim 1, characterized in that, In step S3, two or more shielding bodies that have completed quantitative shielding performance tests are used to predict arbitrary shielding effectiveness, specifically including: In an open electromagnetic environment, the target performance parameters are tested according to the testing standards, and their value is obtained as D. open ; The equipment under test is placed inside a shielded enclosure with precisely calibrated shielding effectiveness. The target performance parameters are then tested according to the testing standards, and the value is determined to be D. s1 ; The equipment under test is then placed inside another shielded enclosure whose shielding effectiveness has been precisely calibrated. The target performance parameters are then tested according to the testing standards, and the value is determined to be D. s2 ; If there are multiple shielding elements, continue to measure the target performance parameter value D for each shielding element. sn ; Let the desired performance index value under the ideal electromagnetic environment be set as D. ideal Then there is D open =D ideal +ΔD=D ideal +f P1 (E i ) Wherein, parameter D ideal and E i The value is obtained by the least squares method, yielding the calculated predicted value of this performance parameter under ideal electromagnetic conditions. pass Introducing Arbitrary Shielding Effectiveness A cn Calculated and predicted values ​​of performance parameters under shielding effect.

3. The electromagnetic environment control method for performance testing of electrophysiological acquisition medical devices according to claim 2, characterized in that, In step S3, an external interference electromagnetic field strength detection device is used to measure the interference field strength at the detection site in real time, thereby predicting the shielding effectiveness of any object. Specifically, this includes: Among them, E i For the parameters obtained using the least squares method, A cn It is the pre-measured shielding effectiveness value, D sn The target performance parameter value measured in this shielding measurement is D. ideal The least squares method is used to obtain the result.

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