CN114778994A - Electromagnetic interference test equipment and method - Google Patents
Electromagnetic interference test equipment and method Download PDFInfo
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- CN114778994A CN114778994A CN202210683275.4A CN202210683275A CN114778994A CN 114778994 A CN114778994 A CN 114778994A CN 202210683275 A CN202210683275 A CN 202210683275A CN 114778994 A CN114778994 A CN 114778994A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/001—Measuring interference from external sources to, or emission from, the device under test, e.g. EMC, EMI, EMP or ESD testing
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
- G01R1/02—General constructional details
- G01R1/18—Screening arrangements against electric or magnetic fields, e.g. against earth's field
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
- G01R1/20—Modifications of basic electric elements for use in electric measuring instruments; Structural combinations of such elements with such instruments
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
- G01R1/28—Provision in measuring instruments for reference values, e.g. standard voltage, standard waveform
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Abstract
The invention discloses an electromagnetic interference test device and method. The equipment comprises an interference signal filtering device, a near field coupling device, a control device and a shielding device; the near-field coupling device and the product to be measured are positioned in the shielding device, and the interference signal filtering device and the control device are positioned outside the shielding device; the cable of the product to be measured is electrically connected with the first end of the near-field coupling device through the interference signal filtering device, and the interference signal filtering device is used for filtering an environmental interference signal; the second end of the near-field coupling device is electrically connected with a product to be detected, and the cable is used for supplying power or transmitting signals to the product to be detected through the interference signal filtering device and the near-field coupling device; the near field coupling device is used for detecting an electromagnetic interference signal of a product to be detected; the control device is electrically connected with the third end of the near-field coupling device and is used for judging whether the product to be detected is qualified or not according to the electromagnetic interference signal. The technical scheme of the embodiment of the invention achieves the effect of improving the efficiency, accuracy and qualification rate of the electromagnetic interference test.
Description
Technical Field
The invention relates to the technical field of testing, in particular to electromagnetic interference testing equipment and method.
Background
Along with the rapid development of electronic products, the anti-interference performance of the electronic products is higher and higher, and the electromagnetic emission indexes of the products exceed the standard requirements and are forbidden to be sold in the market in China.
The electromagnetic interference signal can interfere the normal work of nearby electronic products in a cable conduction mode or a space radiation mode, a conducted interference test is carried out in a shielding room, and the conducted interference test is transmitted to a receiver for measurement and display after being collected by an artificial power network; the radiation interference test is that radiation interference signals of more than 30MHz-1GHz generated in 360-degree directions of the electronic product are received by an antenna in a semi-anechoic chamber, and weak signals are amplified by pre-amplification and then transmitted to a receiver for measurement and display.
The conduction and radiation interference tests are respectively carried out to test the electronic product, more time is needed, the test efficiency is lower, and the test cost is high.
Disclosure of Invention
The invention provides an electromagnetic interference test device and method, which are used for improving the efficiency of electromagnetic interference test and saving the test cost.
According to a first aspect of the present invention, there is provided an electromagnetic interference testing apparatus comprising: the device comprises an interference signal filtering device, a near field coupling device, a control device and a shielding device; the near-field coupling device and a product to be detected are positioned in the shielding device, and the interference signal filtering device and the control device are positioned outside the shielding device;
the cable of the product to be measured is electrically connected with the first end of the near-field coupling device through the interference signal filtering device, and the interference signal filtering device is used for filtering an environmental interference signal;
the second end of the near-field coupling device is electrically connected with the product to be detected, and the cable is used for supplying power or transmitting signals for the product to be detected through the interference signal filtering device and the near-field coupling device; the near field coupling device is used for detecting an electromagnetic interference signal of the product to be detected;
the control device is electrically connected with the third end of the near-field coupling device and is used for judging whether the product to be detected is qualified or not according to the electromagnetic interference signal.
Optionally, the interference signal filtering device includes a high-frequency signal filtering module and a low-frequency signal filtering module;
the cable is electrically connected with the first end of the near field coupling device through the high-frequency signal filtering module and the low-frequency signal filtering module.
Optionally, the high-frequency signal filtering module includes a first high-frequency decoupling magnetic ring; the low-frequency signal filtering module comprises a low-frequency filter;
the cable penetrates through the first high-frequency decoupling magnetic ring to be electrically connected with the first end of the low-frequency filter, and the second end of the low-frequency filter is electrically connected with the first end of the near-field coupling device.
Optionally, the electromagnetic interference test equipment further comprises a second high frequency decoupling magnetic ring; the second high-frequency decoupling magnetic ring is positioned in the shielding device;
and the second end of the low-frequency filter penetrates through the second high-frequency decoupling magnetic ring to be electrically connected with the first end of the near-field coupling device.
Optionally, the near field coupling device comprises a near field probe, a printed circuit board and a printed cable on the printed circuit board;
the second end of the low-frequency filter is electrically connected with the first end of the printed cable, and the second end of the printed cable is electrically connected with the product to be tested; the first end of the printed cable is a first end of the near-field coupling device, and the second end of the printed cable is a second end of the near-field coupling device;
the near-field probe is fixed on the printed cable and is used for detecting an electromagnetic interference signal of the product to be detected; the near-field probes are arranged in one-to-one correspondence with the printed cables; the output end of the near field probe is the third end of the near field coupling device.
Optionally, the near-field coupling apparatus further comprises: a film;
the film covers the surface of the printed circuit board, and the film is used for isolating voltage.
Optionally, the electromagnetic interference testing apparatus further comprises a receiving device;
the control device is electrically connected with the third end of the near-field coupling device through the receiving device, and the receiving device is used for collecting the electromagnetic interference signals detected by the near-field coupling device and sending the electromagnetic interference signals to the control device.
Optionally, the electromagnetic interference testing apparatus further comprises an amplifying device;
the receiving device is electrically connected with the third end of the near-field coupling device through the amplifying device.
According to a second aspect of the present invention, there is provided an electromagnetic interference test method implemented by any of the electromagnetic interference test apparatuses of the first aspect, the electromagnetic interference test method comprising:
acquiring an initial electromagnetic interference signal of a product to be detected, which is detected by a near-field coupling device;
establishing a comparison benchmark according to the initial electromagnetic interference signal and the initial standard test signal;
after the product to be detected is rectified according to the comparison marker post, a rectified electromagnetic interference signal of the rectified product to be detected, which is detected by the near-field coupling device, is obtained;
and determining that the rectification electromagnetic interference signal meets the comparison benchmark, and determining that the product to be tested is qualified when the rectification standard test signal meets a preset value.
Optionally, the establishing a comparison benchmark according to the initial electromagnetic interference signal and the initial standard test signal includes:
the initial standard test signal is subtracted from a standard limit value to obtain a difference value;
and subtracting the difference value according to the initial electromagnetic interference signal to obtain the comparison marker post.
According to the technical scheme of the embodiment of the invention, the cable of the product to be detected is electrically connected with the first end of the near field coupling device through the interference signal filtering device, so that the environmental interference signal of the cable can be filtered, a large error in the detection of the electromagnetic interference signal of the product to be detected is avoided, and the accuracy of the detection of the electromagnetic interference signal of the product to be detected can be improved. The cable is electrically connected with the product to be detected through the near-field coupling device, so that the near-field coupling device can directly detect near-field electromagnetic signals around the product to be detected, the near-field electromagnetic signals of the product to be detected in all directions can be directly detected, the electromagnetic interference signals of the product to be detected can be rapidly detected, and the detection efficiency is improved. The control device can judge whether the product to be detected is qualified according to the electromagnetic interference signal, so that whether the product to be detected is qualified can be determined, in addition, the product to be detected and the near field coupling device are positioned in the shielding device, the shielding device can isolate the electromagnetic interference signal outside the shielding device, a good test environment is provided, the error of detection on the product to be detected can be reduced, and the accuracy of detection on the product to be detected is further improved. The technical scheme of the embodiment of the invention solves the problems that the conduction and radiation interference tests are respectively carried out to test the electronic product, more time is needed, the test efficiency is lower, and the test cost is high, achieves the effects of improving the efficiency, the accuracy and the qualification rate of the electromagnetic interference test, and saves the test cost.
It should be understood that the statements in this section do not necessarily identify key or critical features of the embodiments of the present invention, nor do they necessarily limit the scope of the invention. Other features of the present invention will become apparent from the following description.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a schematic structural diagram of an EMI testing apparatus according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of another EMI testing apparatus according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of a near-field coupling device according to an embodiment of the present invention;
FIG. 4 is a flow chart of a method for testing EMI according to an embodiment of the present invention;
fig. 5 is a flowchart of another emi testing method according to an embodiment of the invention.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, shall fall within the protection scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in other sequences than those illustrated or described herein. Moreover, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Fig. 1 is a schematic structural diagram of an electromagnetic interference testing apparatus provided in an embodiment of the present invention, and referring to fig. 1, the electromagnetic interference testing apparatus includes: the interference signal filtering device 110, the near field coupling device 120, the control device 130 and the shielding device 140; the near-field coupling device 120 and the product 200 to be tested are located in the shielding device 140, and the interference signal filtering device 110 and the control device 130 are located outside the shielding device 140; the cable L1 of the product 200 to be tested is electrically connected to the first end of the near-field coupling device 120 through the interference signal filtering device 110, and the interference signal filtering device 110 is used for filtering an environmental interference signal; the second end of the near-field coupling device 120 is electrically connected to the product 200 to be tested, and the cable L1 is used for supplying power or transmitting signals to the product 200 to be tested through the interference signal filtering device 110 and the near-field coupling device 120; the near field coupling device 120 is used for detecting an electromagnetic interference signal of the product 200 to be detected; the control device 130 is electrically connected to the third end of the near field coupling device 120, and the control device 130 is configured to determine whether the product 200 to be tested is qualified according to the electromagnetic interference signal.
Specifically, the product 200 to be tested is, for example, an electronic product, and when the product 200 to be tested works, power needs to be supplied through the cable L1, or signals are transmitted through the cable L1 and other electronic products, and when the product 200 to be tested works, the electromagnetic interference signals interfere with the product 200 to be tested through the cable L1.
Through the cable L1 with the product 200 that awaits measuring being connected through the first end electricity of interfering signal filter 110 with near field coupling device 120, can filter cable L1's environmental disturbance signal, have great error when avoiding detecting the electromagnetic interference signal of the product 200 that awaits measuring, can improve the accuracy to the electromagnetic interference signal detection of the product 200 that awaits measuring. The cable L1 is electrically connected to the product 200 to be tested through the near-field coupling device 120, so that the near-field coupling device 200 can directly detect the near-field electromagnetic signals around the product 200 to be tested, and thus the near-field electromagnetic signals of the product 200 to be tested in all directions can be directly detected, the electromagnetic interference signals of the product 200 to be tested can be rapidly detected, the detection efficiency is improved, and the test cost is saved. The control device 130 may determine whether the product 200 to be tested is qualified according to the electromagnetic interference signal, for example, may determine whether the electromagnetic interference signal satisfies a preset range, and if the electromagnetic interference signal satisfies the preset range, may determine that the product 200 to be tested is qualified; if the electromagnetic interference signal exceeds the preset range, the product 200 to be detected is judged to be unqualified, and the product 200 to be detected needs to be rectified until the electromagnetic interference signal of the product 200 to be detected meets the preset range, so that the qualification rate of the product can be improved.
In addition, the product 200 to be tested and the near field coupling device 120 are located in the shielding device 140, the shielding device 200 is, for example, a shielding box, the shielding device 140 can isolate electromagnetic interference signals outside the shielding device 140, a good testing environment is provided, the error of detecting the product 200 to be tested can be reduced, and the accuracy of detecting the product 200 to be tested is further improved. Wherein, shielding device 140 can be made through galvanized sheet or steel sheet for example, can be so that shielding device 140 has good shielding performance, and shielding device 140 can set up the shield door, conveniently places the product 200 that awaits measuring.
According to the technical scheme, the cable of the product to be detected is electrically connected with the first end of the near field coupling device through the interference signal filtering device, the environmental interference signal of the cable can be filtered, a large error exists when the electromagnetic interference signal of the product to be detected is avoided, and the accuracy of detecting the electromagnetic interference signal of the product to be detected can be improved. The cable is connected with the product to be detected through the near field coupling device electricity for near field electromagnetic signal around the product to be detected can directly be detected to the near field coupling device, thereby can directly detect the near field electromagnetic signal of the product to be detected in each direction, just can the electromagnetic interference signal of the product to be detected of short-term test, improve detection efficiency. The control device can judge whether the product to be detected is qualified or not according to the electromagnetic interference signal, so that whether the product to be detected is qualified or not can be determined, in addition, the product to be detected and the near field coupling device are positioned in the shielding device, the shielding device can isolate the electromagnetic interference signal outside the shielding device, a good test environment is provided, the error of detection of the product to be detected can be reduced, and the accuracy of detection of the product to be detected is further improved. The technical scheme of this embodiment has solved and has carried out conduction and radiated interference test respectively and test the electronic product, needs more time, and efficiency of software testing is lower, and the lower problem of test accuracy has moreover been reached the effect that improves efficiency, accuracy and the qualification rate of electromagnetic interference test to the test cost has been practiced thrift.
On the basis of the foregoing embodiments, fig. 2 is a schematic structural diagram of another electromagnetic interference testing apparatus provided in an embodiment of the present invention, and optionally, referring to fig. 2, the interference signal filtering device 110 includes a high-frequency signal filtering module 111 and a low-frequency signal filtering module 112; the cable L1 is electrically connected to the first end of the near field coupling device 120 via the high frequency signal filtering module 111 and the low frequency signal filtering module 112.
Specifically, high frequency signal filtering module 111 can filter the high frequency environment interfering signal of cable L1, and low frequency signal filtering module 112 can filter the low frequency environment interfering signal of cable L1 to filtering environmental interfering signal that can be better avoids having great error when detecting the electromagnetic interference signal of the product 200 that awaits measuring, can further improve the accuracy to the product 200 test that awaits measuring.
Optionally, with continued reference to fig. 2, the high frequency signal filtering module 111 includes a first high frequency decoupling magnetic loop 1111; the low frequency signal filtering module 112 includes a low frequency filter 1121; the cable L1 passes through the first high frequency decoupling magnetic ring 1111 and is electrically connected to a first end of the low frequency filter 1121, and a second end of the low frequency filter 1121 is electrically connected to a first end of the near field coupling device 120.
Illustratively, the high-frequency signal filtering module 111 includes a first high-frequency decoupling magnetic ring 1111, through which the cable L1 passes, so as to filter the high-frequency environmental interference signal of the cable L1, so as to conveniently filter the high-frequency environmental interference signal, wherein the first high-frequency decoupling magnetic ring 1111 is, for example, a buckle-type decoupling magnetic ring, and may also be another first high-frequency decoupling magnetic ring. After the cable L1 passes through the first high-frequency decoupling magnetic ring 1111, the cable L1 is electrically connected to the low-frequency filter 1121, and the low-frequency filter 1121 may filter out a low-frequency environmental interference signal of the cable L1, so as to further filter out the environmental interference signal and avoid a large error when detecting the electromagnetic interference signal of the product 200 to be detected.
Optionally, with continued reference to fig. 2, the electromagnetic interference test apparatus further comprises a second high frequency decoupling magnetic loop 150; a second high frequency decoupling magnetic loop 150 is located within the shielding means 140; a second end of the low frequency filter 1121 is electrically connected to a first end of the near field coupling device 120 through a second high frequency decoupling magnetic loop 150.
Specifically, after the cable L1 passes through the low frequency filter 1121 to filter the low frequency environmental interference signal, it passes through the second high frequency decoupling magnetic ring 150, so that the high frequency environmental interference signal can be further removed, and the environmental interference signal existing in the shielding device 140 is avoided, thereby further improving the accuracy of detecting the product 200 to be detected.
Fig. 3 is a schematic structural diagram of a near-field coupling device provided in an embodiment of the present invention, and optionally, referring to fig. 2 and fig. 3, the near-field coupling device 120 includes a near-field probe 121, a printed circuit board 122, and a printed cable 123 located on the printed circuit board 122; the second end of the low-frequency filter 1121 is electrically connected with the first end of the printed cable 123, and the second end of the printed cable 123 is electrically connected with the product 200 to be tested; the first end of printed wire 123 is the first end of near field coupling device 120, and the second end of printed wire 123 is the second end of near field coupling device 120; the near field probe 121 is fixed on the printed cable 123, and the near field probe 121 is used for detecting an electromagnetic interference signal of the product 200 to be detected; the near field probes 121 and the printed cables 123 are arranged in a one-to-one correspondence manner; the output end of the near field probe 121 is the third end of the near field coupling device 120.
Specifically, the second end of the low frequency filter 1121 is electrically connected to the first end of the printed cable 123, and the second end of the printed cable 123 is electrically connected to the product 200 to be tested, so that the cable L1 is connected to the product 200 to be tested through the low frequency filter 1121 and the near field coupling device 120, and the cable L1 can supply power to the product 200 to be tested or transmit signals. The near field probe 121 is fixed to the printed cable 123, so that the near field probe 121 can detect the electromagnetic interference signal propagated by the printed cable 123, that is, can detect the electromagnetic interference signal propagated by the cable L1, that is, can detect the electromagnetic interference signal of the product 200 to be detected. The near-field probes 121 are arranged in one-to-one correspondence with the printed cables 123, so that the electromagnetic interference signals transmitted by each printed cable 123 can be detected, the electromagnetic interference signals of the product 200 to be detected can be comprehensively detected, and the control device 130 can conveniently judge whether the product 200 to be detected is qualified according to the electromagnetic interference signals.
Referring to fig. 3, the printed circuit board 122 is arranged to facilitate coupling of the near field probe 121 and the printed cable 123, and the near field probe 121 may be fixed on the printed cable 123 by a fixing clamp or glue, so that the near field probe 121 and the printed cable 123 are precisely attached to each other, which is beneficial to improving the sensitivity of the near field probe 123.
In addition, the near field probe 121 includes, for example, a broadband near field probe, so that the near field probe 121 can detect electromagnetic interference signals with a large range, and the accuracy of the test is further improved. For example, the printed cables 123 are wide and flat, and can carry a large current, the number of the printed cables 123 may be multiple, and may be determined according to actual situations, and fig. 3 illustrates the case where there are four printed cables 123, but is not limited thereto.
Optionally, with continued reference to fig. 3, the near-field coupling apparatus 120 further comprises: a film 124; the film 124 covers the surface of the printed circuit board 122, and the film 124 serves to isolate the voltage.
Specifically, the film 124 is, for example, a transparent mylar film, and the surface of the printed circuit board 122 is covered by the film 124, so that the high-voltage electrical signal can be isolated, the printed circuit board 122 and the printed cable 123 can be protected, and the transparent film 124 does not cover the printed cable 123, thereby facilitating the test.
Optionally, with continued reference to fig. 2, the electromagnetic interference testing apparatus further comprises a receiving device 160; the control device 130 is electrically connected to the third end of the near field coupling device 120 through the receiving device 160, and the receiving device 160 is configured to collect the electromagnetic interference signal detected by the near field coupling device 120 and send the electromagnetic interference signal to the control device 130.
Specifically, the receiving device 160 includes, for example, a spectrometer or a receiver, and the receiving device 160 may collect an electromagnetic interference signal detected by the near-field coupling device 120, and may send the electromagnetic interference signal to the control device 130, so that the control device 130 determines whether the product 200 under test is qualified according to the electromagnetic interference signal.
Optionally, with continued reference to fig. 2, the electromagnetic interference testing apparatus further comprises an amplifying device 170; the receiving means 160 is electrically connected to the third terminal of the near field coupling means 120 through the amplifying means 170.
Specifically, the amplifying device 170 may amplify the electromagnetic interference signal detected by the near field coupling device 120, and then send the amplified electromagnetic interference signal to the control device 170 through the receiving device 160, so as to analyze the electromagnetic interference signal and realize the test of the product 200 to be tested.
Fig. 4 is a flowchart of an electromagnetic interference testing method according to an embodiment of the present invention, where the electromagnetic interference testing method is implemented by the electromagnetic interference testing apparatus according to any of the above embodiments, and referring to fig. 4, the electromagnetic interference testing method includes:
s410, acquiring an initial electromagnetic interference signal of the product to be detected, which is detected by the near-field coupling device.
Specifically, after the cable is connected with the product to be tested, the near-field coupling device of the electromagnetic interference test equipment is used for quickly measuring the initial electromagnetic interference signal of the product to be tested, and the control device can obtain the initial electromagnetic interference signal of the product to be tested. The near field coupling device can directly detect near field electromagnetic signals around a product to be detected, so that the near field electromagnetic signals of the product to be detected in all directions can be directly detected, the electromagnetic interference signals of the product to be detected can be rapidly detected, and the detection efficiency is improved.
And S420, establishing a comparison benchmark according to the initial electromagnetic interference signal and the initial standard test signal.
Specifically, an initial standard test signal of a product to be tested is tested by using a standard test method, the standard test method is a method combining conduction test and radiation test, a comparison benchmark is established according to the initial electromagnetic interference signal and the initial standard test signal, and then the corresponding relation between the measurement method of the near-field coupling device and the standard measurement method can be established.
And S430, after the product to be detected is rectified according to the comparison marker post, a rectified electromagnetic interference signal of the rectified product to be detected by the near field coupling device is obtained.
Specifically, the product to be detected is rectified according to the comparison marker post, so that the electromagnetic interference signal of the product to be detected is reduced, the rectified product to be detected is detected by the near-field coupling device, the rectified electromagnetic interference signal is obtained, and the control device can obtain the rectified electromagnetic interference signal.
S440, determining that the rectification electromagnetic interference signal meets the comparison benchmark, and determining that the product to be tested is qualified when the rectification standard test signal meets the preset value.
Specifically, the control device compares the rectified electromagnetic interference signal with a comparison marker post, after the rectified electromagnetic interference signal meets the comparison marker post, the rectification of the product to be tested is indicated to be effective, the rectified product to be tested is tested by a standard test method, a rectification standard test signal is obtained, and if the rectification standard test signal meets a preset value, the product to be tested can be determined to be qualified.
According to the technical scheme of the embodiment, the initial electromagnetic interference signal of the product to be tested is quickly measured by using the near-field coupling device of the electromagnetic interference test equipment, and the control device can obtain the initial electromagnetic interference signal of the product to be tested; the near-field coupling device can directly detect near-field electromagnetic signals around a product to be detected, so that the near-field electromagnetic signals of the product to be detected in all directions can be directly detected, the electromagnetic interference signals of the product to be detected can be quickly detected, and the detection efficiency is improved; then testing the initial standard test signal of the product to be tested by using a standard test method, wherein the standard test method is a method combining conduction test and radiation test, establishing a comparison marker post according to the initial electromagnetic interference signal and the initial standard test signal, modifying the product to be tested according to the comparison marker post, so that the electromagnetic interference signal of the product to be detected is reduced, the near-field coupling device detects the rectified product to obtain a rectified electromagnetic interference signal, the control device can obtain the rectified electromagnetic interference signal, the control device compares the rectified electromagnetic interference signal with the comparison marker post, and after the rectified electromagnetic interference signal meets the comparison marker post, and (3) the product to be tested is effectively rectified, the rectified product to be tested is tested by using a standard test method to obtain a rectification standard test signal, and if the rectification standard test signal meets a preset value, the product to be tested is determined to be qualified.
On the basis of the foregoing embodiment, optionally, the step S420 of establishing a comparison benchmark according to the initial electromagnetic interference signal and the initial standard test signal includes:
and a, subtracting the initial standard test signal from the standard limit value to obtain a difference value.
Specifically, the standard limit value is, for example, a limit value when the product to be tested is qualified, the measured initial standard test signal is subtracted from the standard limit value, a difference between the initial standard test signal and the standard limit can be obtained, and a value of the initial standard test signal exceeding the standard limit can be obtained.
And step b, subtracting the difference value according to the initial electromagnetic interference signal to obtain a comparison marker post.
Specifically, the difference is subtracted from the initial electromagnetic interference signal obtained by the test to obtain a comparison benchmark, so that the corresponding relationship between the measurement method of the near-field coupling device and the standard measurement method is established. When the product to be tested is rectified according to the comparison marker post, the standard test signal of the product to be tested can be close to the standard limit, the electromagnetic interference signal of the product to be tested is reduced, and the product to be tested can meet the factory requirements.
Fig. 5 is a flowchart of another electromagnetic interference testing method provided in an embodiment of the present invention, which is a further refinement of S440 in the foregoing embodiment, optionally, with reference to fig. 5, the electromagnetic interference testing method includes:
s510, obtaining an initial electromagnetic interference signal of the product to be detected, which is detected by the near field coupling device.
S520, establishing a comparison benchmark according to the initial electromagnetic interference signal and the initial standard test signal.
And S530, after the product to be detected is rectified according to the comparison marker post, a rectified electromagnetic interference signal of the rectified product to be detected by the near field coupling device is obtained.
S540, judging whether the rectified electromagnetic interference signal meets the comparison benchmark, if not, returning to the step S530; if yes, go to step S550.
Specifically, the control device compares the rectified electromagnetic interference signal with the comparison marker post, when the rectified electromagnetic interference signal meets the comparison marker post, the rectification of the product to be tested is indicated to be effective, and when the rectified electromagnetic interference signal does not meet the comparison marker post, the rectification of the product to be tested is still required, and the step S530 is executed.
And S550, acquiring an adjusting standard test signal.
Specifically, the modified product to be tested is tested by using a standard test method, so that a modified standard test signal can be obtained, and the control device can obtain the modified standard test signal.
S560, judging whether the rectification standard test signal meets a preset value, if not, executing the step S570; if yes, go to step S580.
Specifically, the control device compares the rectification standard test signal with a preset value, if the rectification standard test signal meets the preset value, the product to be tested is determined to be qualified, if the rectification standard test signal does not meet the preset value, the comparison target rod needs to be modified according to the rectification standard test signal, and then the product to be tested is rectified according to the modified comparison target rod.
S570, modifying the comparison benchmarks according to the modified standard test signals, and returning to the step S530.
Specifically, when the rectification standard test signal does not satisfy the preset value, the comparison target needs to be modified according to the rectification standard test signal, and then the product to be tested needs to be rectified according to the modified comparison target.
And S580, determining that the product to be tested is qualified.
It should be understood that various forms of the flows shown above, reordering, adding or deleting steps, may be used. For example, the steps described in the present invention may be executed in parallel, sequentially, or in different orders, and are not limited herein as long as the desired result of the technical solution of the present invention can be achieved.
The above-described embodiments should not be construed as limiting the scope of the invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may be made in accordance with design requirements and other factors. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. An electromagnetic interference testing apparatus, comprising: the device comprises an interference signal filtering device, a near field coupling device, a control device and a shielding device; the near-field coupling device and a product to be measured are positioned in the shielding device, and the interference signal filtering device and the control device are positioned outside the shielding device;
the cable of the product to be measured is electrically connected with the first end of the near-field coupling device through the interference signal filtering device, and the interference signal filtering device is used for filtering an environmental interference signal;
the second end of the near-field coupling device is electrically connected with the product to be detected, and the cable is used for supplying power or transmitting signals for the product to be detected through the interference signal filtering device and the near-field coupling device; the near field coupling device is used for detecting an electromagnetic interference signal of the product to be detected;
the control device is electrically connected with the third end of the near-field coupling device and is used for judging whether the product to be detected is qualified or not according to the electromagnetic interference signal.
2. The electromagnetic interference test equipment of claim 1, wherein the interference signal filtering device comprises a high frequency signal filtering module and a low frequency signal filtering module;
the cable is electrically connected with the first end of the near field coupling device through the high-frequency signal filtering module and the low-frequency signal filtering module.
3. The EMI testing device of claim 2 wherein said high frequency signal filtering module includes a first high frequency decoupling magnetic loop; the low-frequency signal filtering module comprises a low-frequency filter;
the cable penetrates through the first high-frequency decoupling magnetic ring to be electrically connected with the first end of the low-frequency filter, and the second end of the low-frequency filter is electrically connected with the first end of the near-field coupling device.
4. The EMI testing apparatus as set forth in claim 3 further including a second high frequency decoupling magnetic loop; the second high-frequency decoupling magnetic ring is positioned in the shielding device;
and the second end of the low-frequency filter penetrates through the second high-frequency decoupling magnetic ring to be electrically connected with the first end of the near-field coupling device.
5. The EMI testing apparatus of claim 4 wherein said near field coupling means includes a near field probe, a printed circuit board and a printed cable on said printed circuit board;
the second end of the low-frequency filter is electrically connected with the first end of the printed cable, and the second end of the printed cable is electrically connected with the product to be tested; the first end of the printed cable is a first end of the near-field coupling device, and the second end of the printed cable is a second end of the near-field coupling device;
the near-field probe is fixed on the printed cable and is used for detecting an electromagnetic interference signal of the product to be detected; the near-field probes are arranged in one-to-one correspondence with the printed cables; the output end of the near field probe is the third end of the near field coupling device.
6. The EMI testing apparatus of claim 5, wherein said near-field coupling means further comprises: a film;
the film covers the surface of the printed circuit board, and the film is used for isolating voltage.
7. The EMI testing apparatus of claim 1, further comprising receiving means;
the control device is electrically connected with the third end of the near-field coupling device through the receiving device, and the receiving device is used for collecting electromagnetic interference signals detected by the near-field coupling device and sending the electromagnetic interference signals to the control device.
8. The EMI testing apparatus of claim 7, further comprising amplifying means;
the receiving device is electrically connected with the third end of the near-field coupling device through the amplifying device.
9. An electromagnetic interference test method implemented by the electromagnetic interference test apparatus of any one of claims 1 to 8, the electromagnetic interference test method comprising:
acquiring an initial electromagnetic interference signal of a product to be detected, which is detected by a near-field coupling device;
establishing a comparison benchmark according to the initial electromagnetic interference signal and the initial standard test signal;
after the product to be detected is rectified according to the comparison marker post, a rectified electromagnetic interference signal of the rectified product to be detected, which is detected by the near-field coupling device, is obtained;
and determining that the rectification electromagnetic interference signal meets the comparison benchmark, and determining that the product to be tested is qualified when the rectification standard test signal meets a preset value.
10. The emi testing method of claim 9, wherein the establishing a reference bar according to the initial emi signal and the initial standard test signal comprises:
the initial standard test signal is subtracted from a standard limit value to obtain a difference value;
and subtracting the difference value according to the initial electromagnetic interference signal to obtain the comparison marker post.
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| CN202210683275.4A CN114778994A (en) | 2022-06-17 | 2022-06-17 | Electromagnetic interference test equipment and method |
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Application publication date: 20220722 |