Radio frequency electromagnetic field immunity test method

Abstract

The invention relates to the technical field of electromagnetic compatibility, and discloses a wireless radio frequency electromagnetic field immunity test method, which comprises the following steps of S1, generating a continuous wave radio frequency signal in a frequency band of 80MHz-6GHz through a programmable radio frequency signal generation device; s2, constructing an orthogonal polarization electromagnetic field in the radiation test area; s3, three-dimensional space field intensity distribution is monitored in real time based on the 16-channel digital probe array, and a space field intensity distribution cloud picture is generated; s4, synchronously monitoring performance parameters of the tested equipment through an optical coupler isolation acquisition channel; s5, using a slope type field intensity incremental method to increase the field intensity at a step length less than or equal to 1V / m; and S6, establishing a field intensity-performance incidence matrix, generating a three-dimensional electromagnetic vulnerability distribution map, and outputting an immunity grade index. A multi-system interference scene in a real complex electromagnetic environment can be simulated through a programmable radio frequency signal generating device and a time division multiplexing mechanism in combination with carrier frequency hopping and modulation depth gradual change.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic compatibility, and in particular to a method for testing wireless radio frequency electromagnetic field immunity. Background Art

[0002] With the popularization of wireless communication technology and the widespread use of intelligent devices, the electromagnetic environment in which electronic devices operate has become complex, characterized by the coexistence of multiple frequency bands and the interweaving of multiple modulation methods. Radio frequency electromagnetic field interference can cause device malfunctions and communication interruptions. Therefore, electromagnetic compatibility (EMC) testing, as a core method for evaluating device immunity, has a scientifically sound technical solution that directly impacts device reliability in real-world scenarios.

[0003] In existing technologies, testing methods for radio frequency electromagnetic field immunity are mainly based on simulating a single interference scenario using a single modulation mode. Existing test systems have difficulty achieving real-time switching and coordinated superposition of different modulation modes, nor can they dynamically simulate complex electromagnetic interference characteristics such as carrier frequency hopping, modulation depth gradients, and burst pulse interference. This single test mode leads to significant differences between the test environment and the actual electromagnetic environment. In actual applications, equipment may face cross-interference from multiple modulation signals and the superposition of transient burst pulses at the same time. However, traditional methods cannot effectively reproduce such scenarios, making it difficult to fully explore the potential sensitive risks of equipment under the coordinated effects of multiple interferences.

[0004] The above-mentioned existing technologies have at least the following technical problems: the traditional immunity test method lacks the ability to simulate multiple modulation modes, resulting in potential electromagnetic sensitivity risks of the equipment in complex electromagnetic environments. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a wireless radio frequency electromagnetic field immunity testing method, which solves the problem that traditional immunity testing methods lack multi-modulation mode composite simulation capabilities, resulting in potential electromagnetic sensitivity risks of equipment in complex electromagnetic environments.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: A wireless radio frequency electromagnetic field immunity testing method comprises the following steps:

[0007] S1. Generate a continuous wave radio frequency signal in the 80 MHz-6 GHz frequency band through a programmable radio frequency signal generator, and load at least three modulation modes in real time through a time division multiplexing mechanism, wherein the modulation modes include periodic switching of AM, FM, and PM modulation;

[0008] S2. Construct an orthogonally polarized electromagnetic field within the radiation test area, using a horizontally polarized antenna group to cover the 80MHz-3GHz frequency band and a vertically polarized antenna group to cover the 1GHz-6GHz frequency band. Continuous coverage of the entire frequency band is achieved through an antenna switching matrix with nanosecond-level switching speeds.

[0009] S3, based on a 16-channel digital probe array to monitor the three-dimensional field intensity distribution in real time, combined with the built-in standard field intensity reference source for dynamic calibration, to generate a spatial field intensity distribution cloud map;

[0010] S4. Synchronously monitor the performance parameters of the device under test through the optically isolated acquisition channel, including bit error rate, response time, and communication protocol status;

[0011] S5: Use a ramp-type field strength increase method to increase the field strength in steps of ≤1V / m. When an abnormal device performance is detected, a fallback test with a step size of 0.5V / m is automatically triggered, and the validity of the abnormality is determined based on a two-out-of-three voting mechanism.

[0012] S6. Establish a field strength-performance correlation matrix, generate a three-dimensional electromagnetic vulnerability distribution map, and output the immunity level index.

[0013] By adopting the above technical solution, the periodic switching and multi-feature superposition of AM, FM, and PM modulation modes are realized through a programmable RF signal generator and a time-division multiplexing mechanism. The orthogonal polarization antenna group and the high-speed switching matrix are used to construct an orthogonal electromagnetic field with continuous coverage of a wide frequency band (80MHz-6GHz). The 16-channel digital probe array is used to monitor the three-dimensional field strength distribution in real time and dynamically calibrate it. The multi-protocol performance parameters of the equipment are synchronously collected through the optical coupler isolation channel. The ramp-type field strength increase and the three-out-of-two voting mechanism are used to accurately determine the effectiveness of the anomaly. Finally, the three-dimensional electromagnetic vulnerability map and the immunity level index are generated through field strength-performance correlation analysis. This solves the problem of missed detection of potential sensitive hidden dangers of equipment due to insufficient multi-modulation composite simulation capabilities in traditional testing, and realizes high-precision, full-scene quantitative evaluation of immunity in complex electromagnetic environments.

[0014] Preferably, the modulation mode switching includes carrier frequency hopping, modulation depth gradual change and burst pulse superposition with a duration of 1ms-10s. Each modulation mode lasts for at least 10 modulation cycles, and each test cycle includes two modes: forward sweep and reverse sweep.

[0015] Preferably, the three-dimensional spatial field strength monitoring includes collecting field strength data at a spatial resolution of 10 cm and calculating a field strength uniformity calibration factor in real time.

[0016] Preferably, the abnormality validity determination requires that the equipment performance abnormality lasts for ≥100ms, and the abnormality signal is triggered at least twice in three consecutive detections, in order to be determined as a valid failure event.

[0017] Preferably, the ramp-type field strength increasing method includes setting the initial field strength value, adaptively adjusting the step length, and judging the test termination condition. When no abnormality is detected within 5 consecutive increasing steps, the current frequency band test is automatically terminated.

[0018] Preferably, when generating a three-dimensional electromagnetic vulnerability distribution map, the internal circuit board layout data of the device is mapped with the spatial field strength distribution, and the field strength sensitive areas and critical failure thresholds are marked.

[0019] Preferably, the bit error rate test supports RS232 / CAN / LAN multi-protocol synchronous monitoring, and an optocoupler isolation barrier with a withstand voltage level of ≥5kV is set between the acquisition channel and the device under test.

[0020] Preferably, the sweep rate is dynamically adjusted during the test, supporting continuous changes in the range of 0.1-100 MHz / s, and the device immunity threshold offset at different sweep rates is recorded.

[0021] Preferably, the calculation of the immunity level index integrates the sensitivity threshold curve, failure mechanism analysis and time domain waveform distortion characteristics to generate a standard compatibility report including spectrum feature comparison.

[0022] Preferably, after the test is completed, a multi-dimensional data association report is automatically generated, including the spatial field intensity peak distribution, equipment failure time series and modulation mode-failure probability association matrix, and the compliance judgment results of IEC61000-4-3 and GB / T17626.3 standards are compared.

[0023] The present invention provides a method for testing radio frequency electromagnetic field immunity. It has the following beneficial effects:

[0024] 1. This invention utilizes a programmable RF signal generator and a time-division multiplexing mechanism to implement periodic switching and burst pulse superposition among AM, FM, and PM modulation modes. Combined with carrier frequency hopping and gradual modulation depth variation, it can simulate multi-standard interference scenarios found in complex real-world electromagnetic environments. Compared to traditional single-modulation mode testing, this method can more comprehensively expose potential electromagnetic sensitivity risks in equipment, enhancing the engineering practicality of test results.

[0025] 2. This invention utilizes a ramped field intensity increase method combined with a 0.5V / m fallback test and a two-out-of-three voting mechanism. This method requires that the device anomaly persist for ≥100ms and be triggered at least twice in three consecutive tests. This effectively eliminates transient noise interference and increases anomaly detection accuracy to over 99%. Compared to traditional single-shot detection, this significantly reduces the false positive rate and ensures accurate detection of critical failure thresholds.

[0026] 3. The optocoupler isolation acquisition channel of the present invention supports RS232 / CAN / LAN multi-protocol synchronous monitoring, realizes the electrical isolation acquisition of the performance parameters of the device under test, avoids the monitoring channel itself from being affected by electromagnetic interference, and the timing unit with 1μs time resolution and 10μs time alignment accuracy ensures the spatiotemporal synchronization of field intensity changes and device responses, providing accurate timing correlation data for failure mechanism analysis.

[0027] 4. The optocoupler isolation acquisition channel of the present invention supports RS232 / CAN / LAN multi-protocol synchronous monitoring, realizes the electrical isolation acquisition of the performance parameters of the device under test, avoids the monitoring channel itself from being affected by electromagnetic interference, and the timing unit with 1μs time resolution and 10μs time alignment accuracy ensures the spatiotemporal synchronization of field intensity changes and device responses, providing accurate timing correlation data for failure mechanism analysis.

[0028] 5. This invention utilizes orthogonally polarized antenna arrays coupled with an antenna switching matrix capable of nanosecond-level switching speeds to address coverage blind spots in wideband testing. A polarization optimization algorithm ensures field strength uniformity within ±3dB in the 2GHz-3GHz overlapping frequency band. Furthermore, a 16-channel digital probe array monitors three-dimensional field strength distribution in real time with a 10cm spatial resolution. Combined with dynamic calibration using a built-in standard reference source, this array generates high-precision field strength distribution cloud maps, providing a reliable spatial field strength data foundation for device immunity assessment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a flow chart of a wireless radio frequency electromagnetic field immunity testing method of the present invention. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] Please see the attached Figure 1 , an embodiment of the present invention provides a wireless radio frequency electromagnetic field immunity testing method, comprising the following steps:

[0032] S1. Generate a continuous wave radio frequency signal in the 80 MHz-6 GHz frequency band through a programmable radio frequency signal generator, and load at least three modulation modes in real time through a time division multiplexing mechanism, wherein the modulation modes include periodic switching of AM, FM, and PM modulation;

[0033] S2. Construct an orthogonally polarized electromagnetic field within the radiation test area, using a horizontally polarized antenna group to cover the 80MHz-3GHz frequency band and a vertically polarized antenna group to cover the 1GHz-6GHz frequency band. Continuous coverage of the entire frequency band is achieved through an antenna switching matrix with nanosecond-level switching speeds.

[0034] S3, based on a 16-channel digital probe array to monitor the three-dimensional field intensity distribution in real time, combined with the built-in standard field intensity reference source for dynamic calibration, to generate a spatial field intensity distribution cloud map;

[0035] S4. Synchronously monitor the performance parameters of the device under test through the optically isolated acquisition channel, including bit error rate, response time, and communication protocol status;

[0036] S5: Use a ramp-type field strength increase method to increase the field strength in steps of ≤1V / m. When an abnormal device performance is detected, a fallback test with a step size of 0.5V / m is automatically triggered, and the validity of the abnormality is determined based on a two-out-of-three voting mechanism.

[0037] S6. Establish a field strength-performance correlation matrix, generate a three-dimensional electromagnetic vulnerability distribution map, and output the immunity level index.

[0038] Specifically, a programmable RF signal generator is first used to generate a continuous wave RF signal covering a wide frequency band of 80MHz to 6GHz, and three modulation modes, AM amplitude modulation, FM frequency modulation, and PM phase modulation, are dynamically loaded based on a time-division multiplexing control architecture. Among them, the depth of AM modulation varies according to a preset gradient in the range of 30%-80%, the FM modulation frequency deviation is set to ±5% of the carrier frequency, and the PM phase offset is controlled in the range of 0°-180°. The three modulation modes are periodically rotated to realize composite electromagnetic environment simulation. In each modulation cycle, burst pulse interference with a duration of 1ms to 10s is synchronously superimposed. Among them, optocoupler isolation is an isolation technology that uses optical signals to transmit electrical signals. Electrical isolation between circuits is achieved through optocouplers, which can effectively suppress noise interference and avoid the influence of ground loops. It is often used in mixed strong and weak current systems or circuits that require electrical isolation. The three-out-of-two voting mechanism votes on the output results by deploying three identical or redundant sensors, modules or systems. When two or more results are consistent, the result is adopted as the final output to eliminate the impact of a single device failure on the system. It is commonly used in aerospace, industrial control and other fields with extremely high safety requirements.

[0039] During the test field construction phase, a collaborative radiation mode of dual antenna groups with horizontal and vertical polarization was adopted: the horizontally polarized antenna group operated in the low-frequency band of 80MHz-3GHz, and the vertically polarized antenna group covered the high-frequency band of 1GHz-6GHz. The two antenna groups were seamlessly connected through a radio frequency switching matrix with a response speed of nanoseconds. In the overlapping frequency band of 2GHz-3GHz, the system automatically executed the polarization direction optimization algorithm and dynamically adjusted the antenna excitation weight according to the real-time field strength uniformity detection results to ensure that the spatial consistency error of the radiation field strength in the entire frequency band was less than ±3dB. A 16-channel digital field strength probe array was arranged at the center of the radiation area. Each probe formed a three-dimensional monitoring grid with a spacing of 10cm. It was calibrated online with the built-in 50V / m standard field strength reference source. The three-dimensional field strength distribution cloud map was reconstructed through the spatial interpolation algorithm, and the field strength peak position and gradient change trend were displayed in real time.

[0040] The performance monitoring of the device under test utilizes multiple isolation mechanisms. Optocoupler isolation modules with a withstand voltage rating of ≥5kV collect RS232, CAN, and LAN protocol data streams from the device's communication interfaces, simultaneously detecting changes in bit error rate and protocol handshake anomalies. A timing unit with 1μs resolution measures the response delay of device control commands. All monitoring channels are strictly synchronized with the field intensity ramp-up process, with time alignment accuracy controlled within 10μs. Field intensity application utilizes an intelligent ramp-up strategy, gradually increasing the radiation intensity with an initial step size of 1V / m. If any of the following anomalies are detected: a bit error rate exceeding 10^-6, a 50% increase in response latency, or a loss of synchronization in the communication protocol, a reverse fallback test with a step size of 0.5V / m is immediately initiated. A two-out-of-three voting mechanism verifies the persistence of the anomaly. A valid failure is considered only if at least two of three independent acquisitions record the same anomaly lasting for more than 100ms.

[0041] During the test data post-processing phase, the system spatially maps the 3D field intensity distribution data with the internal circuit layout of the device under test, establishing a correlation matrix between field strength, polarization direction, and device functional anomalies. A convolutional neural network algorithm is then used to identify electromagnetically sensitive hotspots and calculate the critical failure threshold for each sensitive point. The final output is an immunity assessment report containing a 3D electromagnetic vulnerability distribution map. Quantitative indicators include: sensitivity curves for the entire 80MHz-6GHz frequency range in the frequency domain, field penetration depth and coupling paths in the spatial domain, and time series characteristics of abnormal events in the time domain.

[0042] Modulation mode switching includes carrier frequency hopping, modulation depth gradient and burst pulse superposition with a duration of 1ms-10s. Each modulation mode lasts for at least 10 modulation cycles, and each test cycle includes two modes: forward sweep and reverse sweep.

[0043] Specifically, the carrier frequency jumps in 5MHz steps within the range of 80MHz-6GHz, maintaining at least 10 full modulation cycles after each jump to account for device response hysteresis. A nonlinear gradual modulation strategy is used, with the AM modulation depth increasing from 30% to 80% in 5% increments per cycle. The FM frequency deviation is dynamically adjusted from ±2% to ±8% of the carrier frequency, while the PM phase offset varies continuously in a sinusoidal pattern from 0° to 180°. Furthermore, programmable burst pulses of 1ms-10s are superimposed during the modulation mode, with pulse intervals randomly distributed between 50ms and 2s. The peak power is 6-10dB higher than the carrier level to simulate transient electromagnetic interference.

[0044] The test cycle design adopts a two-way frequency sweep verification mechanism: the forward sweep phase linearly sweeps from low frequency to high frequency at a rate of 0.1MHz / s, and the reverse sweep phase switches to a high rate of 100MHz / s to scan from high frequency to low frequency. A complete modulation mode sequence is executed in each sweep direction. In particular, when testing in high-frequency bands with carrier frequencies exceeding 3GHz, the system automatically activates the frequency fine-tuning module to compensate for the frequency deviation introduced by antenna switching with an accuracy of 1MHz to ensure the phase continuity of the sweep process. The duration of each modulation mode is controlled by a dynamic counter. When a transient anomaly is detected in the device, the current modulation mode is automatically extended to 20 cycles to verify the reproducibility of the anomaly, and the abnormal frequency point and the corresponding modulation parameter combination are marked in the sweep log.

[0045] Three-dimensional field strength monitoring includes collecting field strength data at a spatial resolution of 10 cm, calculating the field strength uniformity calibration factor in real time, and dynamically correcting the field strength distribution in the test area through a three-dimensional field strength reconstruction module.

[0046] Specifically, when implementing three-dimensional space field strength monitoring, a 16-channel digital probe array is used to build a multi-layer detection network: probe nodes are deployed at equal intervals of 10 cm along the X / Y / Z axes of the test area, a 4×4 matrix probe group is arranged on the horizontal plane, and four layers of detection planes are set in the vertical direction to form a 0.5m 3 A dense grid of monitoring units. Each probe has a built-in temperature compensation circuit, maintaining a ±0.5dB measurement accuracy in an ambient temperature range of -20°C to +60°C. The sampling rate is set to 1MS / s to capture millisecond-level field intensity fluctuations. During real-time calibration, the system activates the built-in 50V / m standard field strength reference source every 30 seconds. By comparing the response values ​​of each probe in the reference field, the system calculates the position-dependent calibration factor α(x,y,z) = V_ref / V_meas and dynamically updates it to the field strength calculation model.

[0047] The abnormal validity judgment requires that the equipment performance abnormality lasts ≥100ms and the abnormal signal is triggered at least twice in three consecutive tests to be judged as a valid failure event.

[0048] Specifically, the validity of the anomaly is determined through a high-precision timestamp synchronization mechanism and a three-level verification process. The system continuously samples the performance parameters of the device under test at intervals of 100 μs. When the bit error rate exceeds 1×10 -5 , when abnormal events such as response delay increased by 50% or communication protocol handshake failure occur, time continuity verification is triggered first: the abnormal signal must maintain a continuous state of at least 100ms, and this period must contain abnormal data records of no less than 1000 sampling points (corresponding to 100ms ÷ 100μs / point = 1000 points) to eliminate transient noise interference.

[0049] After confirming the time persistence, the system initiates a two-out-of-three voting verification mechanism: within one second of the first detection of a valid abnormal signal, it automatically performs two additional independent tests (each test is separated by 200ms), forming a three-test cycle. If at least two of the three tests contain abnormal signals that meet the above time persistence requirements, it is determined to be a valid failure event.

[0050] In order to quantify the stability of the abnormal signal, the sliding window integration algorithm is used to calculate the abnormal energy integral value Among them A i is the abnormal amplitude of the i-th sampling point (the normal state is set to 0, and the abnormal state is assigned a value of 1-3 according to the severity), W i is a weight factor that decays over time (the weight of the most recent 100 μs sampling point is 1, and the weight decreases by 0.1 every 100 μs). When E is greater than or equal to 200 and meets the above-mentioned time continuity and voting mechanism, it is finally determined that the device has an effective electromagnetic interference failure event.

[0051] The ramp-type field strength increment method includes initial field strength value setting, step size adaptive adjustment and test termination condition judgment. When no abnormality is detected within 5 consecutive increment steps, the current frequency band test is automatically terminated.

[0052] Specifically, the system automatically generates an initial field strength curve based on the device type being tested: starting at 3V / m for Class I (industrial) devices and 1V / m for Class II (civilian) devices. Frequency band compensation is performed according to the formula E_init = E_baseline + K·Δf, where E_baseline is the base field strength value, K = 0.05V / (m·MHz) is the frequency response coefficient, and Δf is the offset relative to the reference frequency. When the ambient temperature exceeds 25°C, the initial field strength is automatically adjusted down by 0.3V / m for every 5°C increase in temperature to compensate for temperature drift.

[0053] The field strength increase process adopts an adaptive step size algorithm, with the basic step size set to 0.5V / m and dynamically adjusted according to real-time monitoring data: when the device parameter fluctuation is less than 5%, the step size is gradually increased by 0.1V / m to the upper limit of 1V / m; if the parameter fluctuation exceeds 15%, the step size is immediately reduced to 0.2V / m. After each field strength increase, the system maintains this state for 10 seconds to ensure stable device response. During this period, the parameter standard deviation σ is calculated using the moving time window algorithm. The next step of increase will be executed only when the σ value is lower than the threshold for three consecutive times.

[0054] The test termination judgment adopts a three-level confirmation mechanism: first, the pre-termination check is started when no abnormality is triggered after 5 consecutive incremental steps (cumulative increase ≥ 2.5V / m); then, a steady-state test is performed for 30 seconds at the last field strength value E_max reached, while quickly sweeping the frequency deviation range of ±2%; finally, the antenna polarization direction is switched and the test is repeated. After all three verifications are passed, the system automatically records E_max as the critical value of the frequency band, and sets the warning line for subsequent tests according to the rule of E_test = E_max + 3dB. During the whole process, the system draws the field strength-parameter change curve in real time. When the slope of the curve suddenly changes and exceeds the preset threshold, the current test status is automatically saved, and the possible sensitive point location is prompted.

[0055] To ensure test reliability, the system features a built-in exception handling routine. When encountering transient interference, a retry mechanism automatically initiates, repeating the test three times while maintaining the current field strength. If a recoverable anomaly occurs, the device undergoes a rollback test in 0.1V / m steps until the anomaly disappears, and the precise failure threshold is recorded. All test data is accompanied by a timestamp and environmental parameter records, enabling full-cycle retrospective analysis of the test process. This solution, through dynamic step size adjustment and a multi-level verification mechanism, reduces typical test times by 35%-40% while maintaining test accuracy.

[0056] When generating a three-dimensional electromagnetic vulnerability distribution map, the internal circuit board layout data of the equipment is mapped with the spatial field strength distribution, and the field strength sensitive areas and critical failure thresholds are marked.

[0057] Specifically, when generating a three-dimensional electromagnetic vulnerability distribution map, the system uses multi-source data fusion technology to achieve precise spatial mapping. First, the device CAD structure file is imported. Using a three-dimensional coordinate transformation algorithm, the circuit board layout data (including component locations, routing paths, and shielding structures) is aligned with the test space coordinate system, with a positioning error controlled within ±0.5mm. The real-time field intensity distribution data is then reconstructed into a 0.1cm resolution voxel model using a spatial interpolation algorithm. Each voxel stores complete electromagnetic parameters, including field intensity amplitude, polarization direction, and frequency components.

[0058] During the mapping process, the system automatically identifies critical circuit areas (such as high-speed signal lines, RF modules, power management ICs, etc.) and applies a sampling density three times that of conventional areas to these areas. For each sensitive component, the field strength coupling coefficient at its location is calculated: K_coupling = ∫∫S(ω)·H(ω)dω, where S(ω) represents the component's frequency response characteristics and H(ω) is the local field strength spectrum. When K_coupling exceeds the threshold in the material database, the system marks the area with a red contour line and displays detailed vulnerability parameters in the sidebar: including critical failure field strength (such as the 1dB compression point of the LNA chip), sensitive frequency bands (such as the switching harmonic frequency of the DC-DC converter), and recommended improvement measures (such as adding a shielding cover or filtering circuit).

[0059] For multi-layer PCB structures, the system uses electromagnetic topology analysis to simulate field penetration depth by solving Maxwell's equations. The system then displays the field attenuation at different levels in a three-dimensional map using semi-transparent color gradations. It also automatically generates vulnerability quantification indicators, including regional sensitivity index, frequency band exposure, and overall risk level. These indicators are then compared with a historical failure case database using a machine learning model to provide a failure probability prediction.

[0060] The resulting 3D atlas supports multimodal interactive viewing: you can rotate and zoom to observe spatial distribution, slice through any cross-sectional data, or focus on a specific component to view its time-frequency-space 3D characteristic curve. The system automatically generates an assessment report with improvement recommendations, highlighting risk areas exceeding Class A limits and providing specific shielding design recommendations and verification methods. All data is stored as standardized engineering files that can be directly imported into EMC simulation software for comparison and verification.

[0061] The bit error rate test supports RS232 / CAN / LAN multi-protocol synchronous monitoring, and an optocoupler isolation barrier with a withstand voltage level of ≥5kV is set between the acquisition channel and the device under test.

[0062] Specifically, when implementing multi-protocol bit error rate testing, the system uses a fully isolated architecture design to ensure the safety and accuracy of the test. For the RS232 interface, the test channel has a built-in ±15kV transient voltage suppressor, and a high-speed optocoupler isolation device achieves 5kV / 1min power frequency withstand voltage isolation. The data transmission rate is adaptively adjusted from 300bps to 115.2kbps, and supports dynamic configuration of parameters such as parity and stop bits. CAN bus monitoring uses a dual-channel redundant design, with each channel equipped with an independent DC-DC isolated power supply and magnetic coupling isolation chip. Even under a bus load rate of 60%, it can still accurately capture error frames as short as 2μs and parse error codes (including bit errors, format errors, CRC errors, etc.) in real time.

[0063] For LAN network testing, the system integrates a 10 / 100 / 1000Mbps three-speed Ethernet isolation transformer to achieve 6kV reinforced insulation at the physical layer. The test software simultaneously monitors MAC layer frame errors and TCP / IP layer data integrity, and supports the following concurrent detection modes: throughput test based on RFC2544, measuring packet loss rate with 1% step accuracy, jitter measurement for delay-sensitive applications with a time resolution of 100ns, protocol consistency test, automatic comparison of IEEE802.3 standard frame structure, all isolation channels are equipped with real-time self-test function, and the following diagnostic process is automatically executed every 5 minutes: optocoupler current transfer ratio (CTR) test to ensure that the attenuation value is within ±10% of the initial value, isolation impedance verification, applying 2.5kV test voltage to detect leakage current <1μA, channel delay calibration, compensating for the delay difference of each channel through standard pulse signal.

[0064] Test data is processed using a triple redundancy check mechanism: CRC-32 verification is performed at the acquisition end, byte comparison is performed after transmission to the processing unit, and an MD5 checksum is appended to the data before final storage. If three consecutive bit errors are detected, the system automatically triggers error source analysis, combining eye diagram scanning and protocol decoding techniques to distinguish between sudden bit errors caused by electromagnetic interference and inherent systematic errors.

[0065] In addition to standard bit error rate statistics, the test report also includes an assessment of the health of the isolation channel, the distribution of error types at each protocol layer (such as the number of active / passive state transition errors on the CAN bus), and time-domain correlation analysis with ambient field strength data. All test data is precisely timestamped (synchronized with IEEE1588, with an error of <1μs), supporting spatiotemporal correlation analysis with 3D field strength distribution maps.

[0066] The sweep rate is dynamically adjusted during the test, supporting continuous changes in the range of 0.1-100MHz / s, and the device immunity threshold offset at different sweep rates is recorded.

[0067] Specifically, during the specific implementation process, the dynamic adjustment of the sweep rate is achieved through the precision control module of the programmable RF signal generator. The system adjusts the sweep rate steplessly in the range of 0.1-100MHz / s according to the response characteristics of the device under test: in the initial stage, a low-speed sweep of 0.1MHz / s is used to capture the sensitive frequency points of the device, and then the rate is gradually increased to 100MHz / s for stress testing. After each rate adjustment, the system automatically records the device immunity threshold at the current sweep rate, and associates the time of occurrence of the abnormal event with the sweep parameters through the timestamp synchronization mechanism. When an abnormal performance of the device is detected, the system will finely adjust the sweep rate in steps of 0.5MHz / s, and repeatedly test the abnormal frequency band to determine the offset pattern of the immunity threshold with the change of the sweep rate. All test data are stored in the database to generate a sweep rate-threshold offset relationship curve, which provides a quantitative basis for the subsequent analysis of the stability of the device under dynamic changes in different electromagnetic environments.

[0068] The immunity level index calculation integrates the sensitivity threshold curve, failure mechanism analysis and time domain waveform distortion characteristics to generate a standard compliance report including spectrum feature comparison. After the test is completed, a multi-dimensional data correlation report is automatically generated, including spatial field intensity peak distribution, equipment failure time series and modulation mode-failure probability correlation matrix, and the compliance judgment results of IEC61000-4-3 and GB / T17626.3 standards are compared.

[0069] Specifically, the immunity level index is calculated through multi-dimensional data analysis. The system first integrates full-band test data, plots a sensitivity threshold curve, and annotates the critical field strength values ​​corresponding to each frequency point. Simultaneously, combined with failure event records, it analyzes the mechanism characteristics of the anomaly, including key parameters such as signal distortion patterns and circuit protection mechanism triggering status. For time-domain analysis, the system extracts waveform data before and after the anomaly occurs, quantifying the degree of waveform distortion, such as rising edge delay and amplitude drop.

[0070] After normalization, all data is input into a comprehensive evaluation algorithm to generate an immunity level index. This index not only reflects the device's overall anti-interference capability but also breaks down frequency band sensitivity levels, such as providing separate scores for high and low frequency bands. The resulting compatibility report includes a spectrum feature comparison chart, visually comparing test results with standard limits such as IEC61000-4-3 and GB / T17626.3. Exceeding standard frequencies are noted, along with recommended improvement measures, providing data support for device optimization.

[0071] Example 1

[0072] Immunity testing of industrial wireless communication base stations

[0073] Test object: A certain type of industrial-grade 5G base station equipment (Class I equipment), operating in the 3.4GHz-3.8GHz frequency band, with RS232 and CAN bus communication interfaces.

[0074] Implementation steps:

[0075] S1 signal generation: A 3.4GHz-3.8GHz continuous wave RF signal is generated by a programmable RF signal generator. AM (modulation index 30%-80%), FM (frequency deviation ±5%), and PM (phase offset 0°-180°) modulation modes are time-division multiplexed. The periodic switching period is 1s, and 1ms burst pulse interference (peak power +6dB) is superimposed.

[0076] S2 field construction: A vertically polarized antenna group is used to cover the 3GHz-6GHz frequency band, seamless radiation is achieved through a ns-level switching matrix, and a polarization direction optimization algorithm is executed in the 3.4GHz-3.8GHz frequency band to ensure that the field strength uniformity error is less than ±3dB.

[0077] S3 field strength monitoring: Deploys a 16-channel digital probe array to collect field strength data in real time with a spatial resolution of 10cm. Combined with dynamic calibration using a built-in 50V / m standard reference source, it generates a three-dimensional field strength distribution cloud map.

[0078] S4 performance monitoring: The RS232 bit error rate and CAN bus error frames are synchronously collected through a 5kV optocoupler isolation module, and the timing unit (1μs resolution) monitors the control command response delay.

[0079] S5 field strength increase: The initial field strength is set to 3 V / m, using a ramp-up method (1 V / m step size). A 0.5 V / m fallback test is triggered when a bit error rate greater than 10^-6 is detected. A two-out-of-three voting mechanism verifies the persistence of the anomaly (≥100 ms and two anomalies in three tests).

[0080] S6 data analysis: A field strength-performance correlation matrix was established, sensitive areas of the base station RF module were marked (critical failure threshold 4.8 V / m), and a three-dimensional electromagnetic vulnerability map was generated. The immunity level index was Class B (compliant with the IEC61000-4-3 standard).

[0081] Example 2

[0082] Immunity testing of civilian smart home gateways

[0083] Test object: A certain brand of smart home gateway (Class II device), operating in the 2.4GHz WiFi and 433MHz ZigBee frequency bands, supporting the LAN communication protocol.

[0084] Implementation steps:

[0085] S1 signal generation: Generates 80MHz-2.5GHz continuous wave signals with modulation modes including AM (40%-60%), FM (±3% frequency deviation), and PM (0°-90° phase shift). The switching period is 500ms and a 5ms burst pulse is superimposed (peak power +8dB).

[0086] S2 field construction: The horizontally polarized antenna group covers the 80MHz-3GHz frequency band, and the vertically polarized antenna group covers the 1GHz-6GHz frequency band. In the 2.4GHz frequency band, the polarization direction is dynamically optimized through the antenna switching matrix.

[0087] S3 Field Strength Monitoring: A 16-channel probe array monitors field strength with a 10cm resolution, calculates uniformity calibration factors in real time, and generates a field strength cloud map showing the field strength gradient in the 433MHz frequency band.

[0088] S4 performance monitoring: Optocoupler isolation collects LAN interface packet loss rate (RFC2544 protocol), synchronously detects ZigBee protocol handshake status, and time alignment accuracy is 10μs.

[0089] S5 field strength increase: initial field strength 1V / m, step size adaptive adjustment (0.2V / m-1V / m), triggering fallback test when packet loss rate > 0.1%, abnormal validity judgment requires that two abnormalities last ≥ 100ms in three consecutive detections.

[0090] S6 Data Analysis: Maps PCB layout data, identifies the power management IC as a sensitive area (critical threshold 2.3V / m), and outputs a three-dimensional vulnerability map and Class C immunity index (some frequency bands exceed the limits of GB / T17626.3, recommending additional shielding measures).

[0091]

[0092] illustrate:

[0093] Modulation mode: The traditional method only supports single modulation, while both the first and second embodiments adopt multi-mode dynamic switching and superimpose burst pulse interference, but the specific parameters (switching period, pulse strength) are adjusted differently according to the device type.

[0094] Frequency band coverage: Traditional methods rely on manual switching of antennas, which has blind spots. Example 1 optimizes the vertically polarized antenna group for the high frequency band (5G), while Example 2 covers a wide frequency band and solves the coexistence problem of multiple protocols through dynamic optimization.

[0095] Field strength control: Traditional methods lack fine control. Example 1 adopts a high-precision ramp increment and fallback mechanism. Example 2 combines adaptive step size and protocol layer abnormality triggering mechanism, which is more suitable for the characteristics of civilian equipment.

[0096] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for testing radio frequency electromagnetic field immunity, characterized in that: The following steps are involved: S1. Generate a continuous wave radio frequency signal in the 80 MHz-6 GHz frequency band through a programmable radio frequency signal generator, and load at least three modulation modes in real time through a time division multiplexing mechanism, wherein the modulation modes include periodic switching of AM, FM, and PM modulation; S2. Construct an orthogonally polarized electromagnetic field within the radiation test area, using a horizontally polarized antenna group to cover the 80MHz-3GHz frequency band and a vertically polarized antenna group to cover the 1GHz-6GHz frequency band. Continuous coverage of the entire frequency band is achieved through an antenna switching matrix with nanosecond-level switching speeds. S3, based on a 16-channel digital probe array to monitor the three-dimensional field intensity distribution in real time, combined with the built-in standard field intensity reference source for dynamic calibration, to generate a spatial field intensity distribution cloud map; S4. Synchronously monitor the performance parameters of the device under test through the optically isolated acquisition channel, including bit error rate, response time, and communication protocol status; S5: Use a ramp-type field strength increment method to increase the field strength in steps of ≤1V / m. When an abnormal device performance is detected, a fallback test with a step size of 0.5V / m is automatically triggered, and the validity of the abnormality is determined based on a two-out-of-three voting mechanism. S6. Establish a field strength-performance correlation matrix, generate a three-dimensional electromagnetic vulnerability distribution map, and output the immunity level index.

2. A wireless radio frequency electromagnetic field immunity testing method according to claim 1, characterized in that: The modulation mode switching includes carrier frequency hopping, modulation depth gradual change and burst pulse superposition with a duration of 1ms-10s. Each modulation mode lasts for at least 10 modulation cycles, and each test cycle includes two modes: forward sweep and reverse sweep.

3. The method for testing radio frequency electromagnetic field immunity according to claim 1, wherein: The three-dimensional spatial field intensity monitoring includes collecting field intensity data at a spatial resolution of 10 cm and calculating a field intensity uniformity calibration factor in real time.

4. The method for testing radio frequency electromagnetic field immunity according to claim 1, wherein: The abnormal validity judgment requires that the equipment performance abnormality lasts for ≥100ms and the abnormal signal is triggered at least twice in three consecutive detections to be determined as a valid failure event.

5. The method for testing radio frequency electromagnetic field immunity according to claim 1, wherein: The ramp-type field strength increasing method includes setting the initial field strength value, adaptively adjusting the step length, and judging the test termination condition. When no abnormality is detected within five consecutive increasing steps, the current frequency band test is automatically terminated.

6. The method for testing radio frequency electromagnetic field immunity according to claim 1, wherein: When generating a three-dimensional electromagnetic vulnerability distribution map, the internal circuit board layout data of the equipment is mapped with the spatial field strength distribution, and the field strength sensitive areas and critical failure thresholds are marked.

7. The method for testing radio frequency electromagnetic field immunity according to claim 1, wherein: The bit error rate test supports RS232 / CAN / LAN multi-protocol synchronous monitoring, and an optocoupler isolation barrier with a withstand voltage level of ≥5kV is set between the acquisition channel and the device under test.

8. The method for testing radio frequency electromagnetic field immunity according to claim 1, wherein: The sweep rate is dynamically adjusted during the test, supporting continuous changes in the range of 0.1-100MHz / s, and the device immunity threshold offset at different sweep rates is recorded.

9. The method for testing radio frequency electromagnetic field immunity according to claim 1, wherein: The calculation of the immunity level index integrates the sensitivity threshold curve, failure mechanism analysis and time domain waveform distortion characteristics to generate a standard compatibility report including spectrum feature comparison.

10. The method for testing radio frequency electromagnetic field immunity according to claim 1, wherein: After the test is completed, a multi-dimensional data correlation report is automatically generated, including the spatial field intensity peak distribution, equipment failure time series, and modulation mode-failure probability correlation matrix, and the compliance judgment results of IEC61000-4-3 and GB / T17626.3 standards are compared.

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