WO2022183795A1

WO2022183795A1 - Performance test apparatus and test method for electromagnetic interference noise separator

Info

Publication number: WO2022183795A1
Application number: PCT/CN2021/133871
Authority: WO
Inventors: 王洪超; 李志刚; 宋喜岗; 姜意驰; 张宝国; 谷原野; 马良; 马文峰; 张翘楚; 姬楠
Original assignee: 一汽奔腾轿车有限公司
Priority date: 2021-03-05
Filing date: 2021-11-29
Publication date: 2022-09-09
Also published as: CN113092892A; CN113092892B

Abstract

A performance test apparatus and test method for an electromagnetic interference noise separator. The apparatus is composed of a conduction noise separator (1) under test, an in-phase power distributor (2), an inverting power distributor (3), a 50Ω matching load (4) and a dual-port network analyzer (5), which are connected by means of a 50Ω coaxial line, wherein the conduction noise separator (1) under test is provided with two input ports (1-1, 1-2) and output ports (1-3, 1-4), which are used for inputting power source line noise signals and outputting a differential-mode noise component and a common-mode noise component, and the inverting power distributor (3) and the in-phase power distributor (2) are used for simulating a differential-mode signal and a common-mode signal. In addition to being used for a performance test of a conduction noise separator, the test method can also be used for a performance test of a filter; the separation and quantization of a common mode and a differential mode are performed on electromagnetic compatibility disturbance conduction noise during a product test process; and scientific and effective targeted guidance is provided for common-mode and differential-mode filter parameters designed for suppressing conduction noise during an electromagnetic compatibility rectification and optimization process.

Description

An electromagnetic interference noise separator performance testing device and testing method

technical field

The invention belongs to the technical field, and in particular relates to an electromagnetic interference noise separator performance testing device and a testing method.

Background technique

Electromagnetic interference noise separator, referred to as separator for short, is a device that is used to conduct electromagnetic interference signal processing at the power port, and output the differential mode component and common mode component of the electromagnetic interference signal separately from different ports. After obtaining the results of the differential mode interference and common mode interference components, the filter can be designed in a targeted manner to improve the performance of the product. The performance of the separator determines the accuracy of the test results. At present, four-port network analyzers are commonly used to test the performance of the splitter, but four-port network analyzers are expensive and the test setup is more complicated. In the differential mode test of the existing test method, the differential mode signal is only injected into the single end of the noise separator, and the other end is grounded, which cannot accurately simulate the influence of the opposite-phase signal at the other end. The transformer causes a risk of impedance mismatch between the signal injection port and the network analyzer port. The above two reasons will affect the accuracy of the test results and limit the test frequency band.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide an electromagnetic interference noise separator performance testing device, and also to provide an electromagnetic interference noise separator performance testing method to solve the problem of accurately measuring conducted noise in a wide frequency range.

The purpose of this invention is to realize through the following technical solutions:

An electromagnetic interference noise separator performance testing device, which is composed of a tested conducted noise separator 1, an in-phase power divider 2, an anti-phase power divider 3, a 50Ω matched load 4 and a dual-port network analyzer 5;

The tested conducted noise separator 1, the in-phase power divider 2, the anti-phase power divider 3, the 50Ω matched load 4 and the dual-port network analyzer 5 are connected through a 50Ω coaxial cable;

The tested conducted noise separator 1 is provided with an input port I11 and an input port II12 for inputting power line noise signals, and an output port I13 and an output port II14 for outputting differential mode noise components and output common noise components respectively. modal noise component;

The in-phase power divider 2 and the in-phase power divider 3 are used for simulating differential mode signals and common-mode signals; wherein, the in-phase power divider 2 is used to generate in-phase signals with equal amplitudes, and an output port is provided on it. III21, output port IV22 and input port III23; the inverting power divider 3 is used to generate an inverse phase signal with equal amplitude and 180° phase difference, and is provided with output port V31, output port VI32 and input port IV33 .

Further, the tested conducted noise splitter 1 and the in-phase power divider 2 are respectively connected to the two-port network analyzer 5 through a 50Ω coaxial cable, and the tested conducted noise splitter 1 is connected to the in-phase power splitter through a 50Ω coaxial cable. 2 is connected, and the 50Ω matched load 4 is connected to the tested conducted noise separator 1 through a 50Ω coaxial cable.

Further, the input port I11 is connected with the output port III21, the input port II12 is connected with the output port IV22, the output port I13 is connected with the 50Ω matched load 4, and the input port III23 and the output port II14 are respectively connected with the dual-port network analyzer 5. .

Further, the input port I11 is connected with the output port III21, the input port II12 is connected with the output port IV22, the output port II14 is connected with the 50Ω matched load 4, and the input port III23 and the output port I13 are respectively connected with the dual-port network analyzer 5. .

Further, the tested conducted noise splitter 1 and the inverting power divider 3 are respectively connected to the two-port network analyzer 5 through a 50Ω coaxial cable, and the tested conducted noise splitter 1 is connected to the inverting power through a 50Ω coaxial cable. The distributor 3 is connected, and the 50Ω matched load 4 is connected to the tested conducted noise separator 1 through a 50Ω coaxial cable.

Further, the input port I11 is connected with the output port V31, the input port II12 is connected with the output port VI32, the output port II14 is connected with the 50Ω matching load 4, and the input port IV33 and the output port I13 are respectively connected with the dual-port network analyzer 5. .

Further, the input port I11 is connected with the output port V31, the input port II12 is connected with the output port VI32, the output port I13 is connected with the 50Ω matching load 4, and the input port IV33 and the output port II14 are respectively connected with the dual-port network analyzer 5. .

Further, the S parameters of the in-phase power divider 2 and the anti-phase power divider 3 need to be obtained through calibration, and in an ideal state, their values are both 3dB.

Further, the phase difference between the output port III21 and the output port IV22 is 0°; the phase difference between the output port V31 and the output port VI32 is 180°

A method for testing the performance of an electromagnetic interference noise separator, comprising the following steps:

A. Within the operating frequency range of the conducted noise separator 1, four parameters are defined: common mode insertion loss, common mode-differential mode isolation, differential mode insertion loss, and differential mode-common mode isolation: common-differential mode separator The differential mode insertion loss is IL _DM , the common mode-differential mode isolation is TR _CM-DM , the differential mode insertion loss of the common differential mode splitter is IL _CM , and the differential mode-common mode isolation is TR _DM-CM ;

B. The power values of several ports are defined as follows:

The differential mode power value injected at input port I11 is defined as P _DM1-1 , and the common mode power value is defined as P _CM1-1 ; the differential mode power value injected at input port II12 is defined as P _DM1-2 , and the common mode power value is defined as P DM1-2 . The value is defined as P _CM1-2 ; the differential mode power value measured at output port I13 is defined as P _DM1-3 , and the common mode power value is defined as P _CM1-3 ; the differential mode power value measured at output port II14 is defined as Defined as P _DM1-4 , the common mode power value is defined as P _CM1-4 ;

C. The phase definition is defined as φ _DMn-m, φ _CMn-m according to the power definition method; where nm is the port number;

D. Conducted noise separator 1 separates the differential mode components of the input signal at input port I11 and input port II12 to output port I13, and the common mode component separately to output port II14, with the following results: P _DM1-3 (dB)= P _DM1-1 (dB)-IL _DM (dB), P _DM1-4 (dB)=P _CM1-1 (dB)-IL _CM (dB); i.e.: IL _DM (dB)=P _DM1-1 (dB )-P _DM1-3 (dB),IL _CM (dB)=P _CM1-1 (dB)-P _DM1-4 (dB);

E. If an ideal common mode signal is injected into input port I11 and input port II12, there are P _CM1-1 =P _CM1-2 , φ _DM1-1 =φ _DM1-2 , P _DM1-1 =P _DM1-2 =0; in the same way, if an ideal differential mode signal is injected into the input port I11 and the input port II12 port, there is P _DM1-1 =P _DM1-2 , φ _DM1-1 -φ _DM1-2 =180°P _{CM1- 1} = P _CM1-2 = 0;

F. Test the common mode insertion loss of the conducted noise splitter: the network analyzer 5 generates a test signal from the output port within the set test frequency range, and decomposes it into two equal amplitudes and a phase difference of 0 through the in-phase power splitter 2 The standard common mode signal of ° is injected into the input port I11 and input port II12 of the conducted noise separator through the output port III21 and the output port IV22. At the other end of the noise separator, the common mode output signal of the output port II14 is measured;

According to the characteristics of the noise separator, its calculation formula is: IL _CM (dB)=S _{cc21_measured} (dB)-S _{13_splitter} (dB); wherein, S _{cc_measured} is the S ₂₁ value of the dual-port network analyzer; S _{13_splitter} is the in-phase power distribution S parameters of the input port and output port of the device, ideally, S _{13_splitter} =S _{23_splitter} =3dB;

G. Test the common mode-differential mode isolation of the conducted noise separator. The signal injection method is the same as step F, but at the other end of the noise separator, the differential mode output signal of the output port I13 needs to be measured;

Since the injected noise source is an ideal common-mode signal and has no differential-mode component, the theoretical value of the signal strength measured at the differential-mode port is 0, and the common-mode-differential-mode isolation is defined as S _{cd21_real} , under ideal conditions, S _{cd21_real} =∞ . But in fact, due to the influence of uncontrollable factors such as impedance matching accuracy and parasitic parameters of components, the results cannot reach the theoretical value. In practical applications, it can be considered that S _{cd21_real} ≥ 30db is the acceptance condition;

H. Test the differential mode insertion loss of the conducted noise separator. The network analyzer 5 generates a test signal from the output port within the set test frequency range, and decomposes it into two equal amplitudes by the inverting power divider 2, and the phase difference is The standard differential mode signal of 180° is injected into the input port I11 and input port II12 of the conducted noise separator through the output port V31 and output port VI32. At the other end of the noise separator, the differential mode output signal of the output port I13 is measured.

Compared with the prior art, the beneficial effects of the present invention are:

The electromagnetic interference noise separator performance testing device and testing method of the present invention use an inverting power divider and an in-phase power divider to simulate differential mode signals and common mode signals;

In addition to being used for the performance test of the conducted noise separator, it can also be used for the performance test of the filter;

Separation and quantification of common mode and differential mode for electromagnetic compatibility disturbance conducted noise during product testing;

Provide scientific and effective targeted guidance for the parameters of common mode and differential mode filters designed to suppress conducted noise in the process of electromagnetic compatibility rectification and optimization;

Conducted noise separators are used to separate the differential mode/common mode components of conducted noise at power ports. Conducted noise separators for consumer products must have good characteristics in the frequency range below 30MHz. Conducted noise separators for automotive products Must have good characteristics in the frequency range below 110MHz.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore do not It should be regarded as a limitation of the scope, and for those of ordinary skill in the art, other related drawings can also be obtained according to these drawings without any creative effort.

Figure 1 Common mode insertion loss test layout;

Figure 2 Common mode-differential mode isolation test layout;

Figure 3 Differential mode insertion loss test layout;

Figure 4 Differential mode-common mode isolation test layout;

Figure 5 is a structural diagram of an electromagnetic interference noise separator performance testing device.

In the figure, 1. Conducted noise separator under test 2. In-phase power divider 3. Inverting power divider 4. Load 5. Two-port network analyzer 11. Input port I 12. Input port II 13. Output port I 14 .Output port II 21. Output port III 22. Output port IV 23. Input port III 31. Output port V 32. Output port VI 33. Input port IV.

Detailed ways

Below in conjunction with embodiment, the present invention is further described:

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention. In addition, it should be noted that, for the convenience of description, the drawings only show some but not all structures related to the present invention.

It should be noted that like numerals and letters refer to like items in the following figures, so once an item is defined in one figure, it does not require further definition and explanation in subsequent figures. Meanwhile, in the description of the present invention, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

As shown in FIG. 1 , the electromagnetic interference noise separator performance testing device of the present invention consists of a tested conducted noise separator 1 , an in-phase power divider 2 , an inverting power divider 3 , a 50Ω matched load 4 and a dual-port network analyzer 5 Composition: The tested conducted noise separator 1 , the in-phase power divider 2 , the anti-phase power divider 3 , the 50Ω matched load 4 and the two-port network analyzer 5 are connected through a 50Ω coaxial cable.

The in-phase power divider 2 is used to generate in-phase signals with equal amplitudes, and is provided with an output port III21, an output port IV22 and an input port III23;

The inverse power divider 3 is used to generate inverse phase signals with equal amplitude and 180° phase difference, and is provided with an output port V31, an output port VI32 and an input port IV33.

The S-parameters of the in-phase power divider 2 and the anti-phase power divider 3 need to be obtained through calibration, and in an ideal state, their values are both 3dB.

The phase difference between the output port III21 and the output port IV22 is 0°.

The phase difference between the output port V31 and the output port VI32 is 180°

Example 1

Common Mode Insertion Loss Test

The tested conducted noise splitter 1 and the in-phase power divider 2 are respectively connected to the two-port network analyzer 5 through a 50Ω coaxial cable, and the tested conducted noise splitter 1 is connected to the in-phase power splitter 2 through a 50Ω coaxial cable, The 50Ω matched load 4 is connected to the tested conducted noise separator 1 through a 50Ω coaxial cable.

The input port I11 is connected with the output port III21, the input port II12 is connected with the output port IV22, the output port I13 is connected with the 50Ω matching load 4, and the input port III23 and the output port II14 are respectively connected with the dual-port network analyzer 5.

Example 2

Common Mode - Differential Mode Isolation Test

The input port I11 is connected with the output port III21, the input port II12 is connected with the output port IV22, the output port II14 is connected with the 50Ω matched load 4, and the input port III23 and the output port I13 are respectively connected with the dual-port network analyzer 5.

Example 3

Differential Mode Insertion Loss Test

The tested conducted noise splitter 1 and the inverting power divider 3 are respectively connected to the two-port network analyzer 5 through a 50Ω coaxial cable, and the tested conducted noise splitter 1 is connected to the inverting power splitter 3 through a 50Ω coaxial cable. The 50Ω matched load 4 is connected to the tested conducted noise separator 1 through a 50Ω coaxial cable.

The input port I11 is connected with the output port V31, the input port II12 is connected with the output port VI32, the output port II14 is connected with the 50Ω matching load 4, and the input port IV33 and the output port I13 are respectively connected with the dual-port network analyzer 5.

Example 4

Differential Mode-Common Mode Isolation Test

The input port I11 is connected with the output port V31, the input port II12 is connected with the output port VI32, the output port I13 is connected with the 50Ω matching load 4, and the input port IV33 and the output port II14 are respectively connected with the dual-port network analyzer 5.

Within the operating frequency range of the conducted noise separator 1, the performance evaluation indicators mainly include four parameters: common mode insertion loss, common mode-differential mode isolation, differential mode insertion loss, and differential mode-common mode isolation. The parameters are defined as follows:

Define the differential mode insertion loss of the common differential mode splitter as IL _DM , and the common mode-differential mode isolation as TR _CM-DM ;

The differential mode insertion loss of the common differential mode separator is defined as IL _CM , and the differential mode-common mode isolation is TR _DM-CM .

The power values for several ports are defined as follows:

The differential mode power value injected at the input port I11 is defined as P _DM1-1 , and the common mode power value is defined as P _CM1-1 ;

Define the differential mode power value injected at the input port II12 as P _DM1-2 , and the common mode power value as P _CM1-2 ;

The differential mode power value measured at the output port I13 is defined as P _DM1-3 , and the common mode power value is defined as P _CM1-3 ;

The differential mode power value measured at output port II14 is defined as P _DM1-4 , and the common mode power value is defined as P _CM1-4 ;

The phase definition is defined as φ _DMn-m, φ _CMn-m according to the power definition method; where nm is the port number.

Conducted noise separator 1 separates the differential mode components of the input signals at input port I11 and input port II12 to output port I13, and the common mode component separately to output port II14, with the following results:

P _DM1-3 (dB)=P _DM1-1 (dB)-IL _DM (dB),

P _CM1-4 (dB)=P _CM1-1 (dB)-IL _CM (dB).

which is:

IL _DM (dB)=P _DM1-1 (dB)-P _DM1-3 (dB),

IL _CM (dB)=P _CM1-1 (dB)-P _DM1-4 (dB).

If an ideal common mode signal is injected into input port I11 and input port II12, there are P _CM1-1 =P _CM1-2 , φ _DM1-1 =φ _DM1-2 , P _DM1-1 =P _DM1-2 =0 ; Similarly, if an ideal differential mode signal is injected into the input port I11 and the input port II12 port, there is P _DM1-1 =P _DM1-2 , φ _DM1-1 -φ _DM1-2 =180°P _CM1-1 = P _CM1-2 =0.

Figure 1 shows the test method for the common mode insertion loss of a conducted noise splitter. The network analyzer 5 generates a test signal from the output port within the set test frequency range. It is a standard common mode signal of 0°, which is injected into the input port I11 and input port II12 of the conducted noise separator through the output port III21 and output port IV22. At the other end of the noise separator, measure the common mode output signal of the output port II14. .

According to the characteristics of the noise separator, its calculation formula is:

IL _CM (dB)=S _{cc21_measured} (dB)-S _{13_splitter} (dB);

Wherein, S _{cc_measured} is the S ₂₁ value of the dual-port network analyzer measured according to the test system shown in Figure 1;

S _{13_splitter} is the S parameter of the input port and the output port of the in-phase power divider, ideally, S _{13_splitter} =S _{23_splitter} =3dB;

Figure 2 shows the common mode-differential mode isolation test method of the conducted noise separator. The signal injection method is the same as Figure 1, but at the other end of the noise separator, the differential mode output signal of the output port I13 needs to be measured.

Since the injected noise source is an ideal common-mode signal and has no differential-mode component, the theoretical value of the signal strength measured at the differential-mode port is 0, and the common-mode-differential-mode isolation is defined as S _{cd21_real} , under ideal conditions, S _{cd21_real} =∞ . But in fact, due to the influence of uncontrollable factors such as impedance matching accuracy and parasitic parameters of components, the result cannot reach the theoretical value. In practical applications, it can be considered that S _{cd21_real} ≥ 30db is an acceptable condition.

Similarly, the test of the differential mode insertion loss of the conducted noise separator is shown in Figure 3. The network analyzer 5 generates a test signal from the output port within the set test frequency range, and is decomposed into two by the inverting power divider 2. The standard differential mode signal with equal amplitude and 180° phase difference is injected into the input port I11 and input port II12 of the conducted noise separator through output port V31 and output port VI32. At the other end of the noise separator, measure the output port I13. Differential mode output signal.

The present invention uses the inverting power divider and the in-phase power divider to simulate the differential mode signal and the common mode signal; the electromagnetic interference noise separator performance testing device and the measuring method can be used not only for the performance test of the conduction noise separator, but also for the filter performance test.

As shown in FIG. 5 , both the LISN and the spectrum analyzer are auxiliary test equipments commonly used in the laboratory, which can assist the related tests of the electromagnetic interference noise separator performance test device of the present invention. The electromagnetic interference noise separator performance testing device of the invention can effectively separate common mode and differential mode signals, so as to achieve the purpose of accurate testing and subsequent targeted rectification. It can separate and quantify the common mode and differential mode of the electromagnetic compatibility disturbance conducted noise during the product testing process; it can provide scientific and effective guidance for the common mode and differential mode filter parameters designed to suppress conducted noise during the electromagnetic compatibility rectification and optimization process. Sexual guidance.

Scope of application of the device: With the help of LISN, it is suitable for noise measurement of parts in the laboratory or the end of the vehicle wiring harness; The output power is less than +30dBm, and the impedance is 50 ohms.

Note that the above are only preferred embodiments of the present invention and applied technical principles. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and can also include more other equivalent embodiments without departing from the concept of the present invention. The scope is determined by the scope of the appended claims.

Claims

An electromagnetic interference noise separator performance testing device, characterized in that: a tested conducted noise separator (1), an in-phase power divider (2), an anti-phase power divider (3), a 50Ω matching load (4) and A dual-port network analyzer (5) is composed;

The measured conducted noise separator (1), the in-phase power divider (2), the anti-phase power divider (3), the 50Ω matched load (4) and the two-port network analyzer (5) pass through a 50Ω coaxial line connected

The tested conducted noise separator (1) is provided with an input port I (11) and an input port II (12) for inputting power line noise signals, and an output port I (13) and an output port II ( 14), respectively used to output differential mode noise components and output common mode noise components;

The inverting power divider (2) and the in-phase power divider (3) are used for simulating differential mode signals and common mode signals; wherein, the in-phase power divider (2) is used for generating in-phase signals with equal amplitudes, There is an output port III (21), an output port IV (22) and an input port III (23) on it; the inverse power divider (3) is used to generate an inverse phase with the same amplitude and a phase difference of 180° There are output port V (31), output port VI (32) and input port IV (33) on it.
The device for testing the performance of an electromagnetic interference noise separator according to claim 1, wherein the tested conducted noise separator (1) and the in-phase power divider (2) pass through a 50Ω coaxial cable and a dual port respectively. The network analyzer (5) is connected, the tested conducted noise separator (1) is connected to the in-phase power divider (2) through a 50Ω coaxial cable, and the 50Ω matched load (4) is connected to the tested conducted noise separator through a 50Ω coaxial cable. (1) Connected.
An electromagnetic interference noise separator performance testing device according to claim 2, characterized in that: the input port I (11) is connected to the output port III (21), and the input port II (12) is connected to the output port IV ( 22) are connected, the output port I (13) is connected with the 50Ω matching load (4), the input port III (23) and the output port II (14) are respectively connected with the dual-port network analyzer (5).
An electromagnetic interference noise separator performance testing device according to claim 2, characterized in that: the input port I (11) is connected to the output port III (21), and the input port II (12) is connected to the output port IV ( 22) are connected, the output port II (14) is connected with the 50Ω matching load (4), the input port III (23) and the output port I (13) are respectively connected with the dual-port network analyzer (5).
An electromagnetic interference noise separator performance testing device according to claim 1, characterized in that: the tested conducted noise separator (1) and the inverting power divider (3) pass through a 50Ω coaxial cable and a dual The port network analyzer (5) is connected, the tested conducted noise separator (1) is connected to the inverting power divider (3) through a 50Ω coaxial cable, and the 50Ω matched load (4) is connected to the tested conducted noise through a 50Ω coaxial cable. The separator (1) is connected.
An electromagnetic interference noise separator performance testing device according to claim 5, characterized in that: the input port I (11) is connected to the output port V (31), and the input port II (12) is connected to the output port VI ( 32) is connected, the output port II (14) is connected with the 50Ω matching load (4), the input port IV (33) and the output port I (13) are respectively connected with the dual-port network analyzer (5).
An electromagnetic interference noise separator performance testing device according to claim 5, characterized in that: the input port I (11) is connected to the output port V (31), and the input port II (12) is connected to the output port VI ( 32) are connected, the output port I (13) is connected with the 50Ω matching load (4), the input port IV (33) and the output port II (14) are respectively connected with the dual-port network analyzer (5).
An electromagnetic interference noise separator performance testing device according to claim 1, characterized in that: the S parameters of the in-phase power divider (2) and the anti-phase power divider (3) need to be obtained through calibration, and the ideal state Below, its value is 3dB.
An electromagnetic interference noise separator performance testing device according to claim 1, characterized in that: the phase difference between the output port III (21) and the output port IV (22) is 0°; the output port V ( The phase difference between 31) and output port VI (32) is 180°.
A method for testing the performance of an electromagnetic interference noise separator, comprising the following steps:

A. Within the operating frequency range of the conducted noise separator 1, four parameters are defined: common mode insertion loss, common mode-differential mode isolation, differential mode insertion loss, and differential mode-common mode isolation: common-differential mode separator The differential mode insertion loss is IL DM , the common mode-differential mode isolation is TR CM-DM , the differential mode insertion loss of the common differential mode splitter is IL CM , and the differential mode-common mode isolation is TR DM-CM ;

B. The power values of several ports are defined as follows:

The differential mode power value injected at input port I (11) is defined as P DM1-1 , the common mode power value is defined as P CM1-1 ; the differential mode power value injected at input port II (12) is defined as P DM1 -2 , the common mode power value is defined as P CM1-2 ; the differential mode power value measured at output port I (13) is defined as P DM1-3 , and the common mode power value is defined as P CM1-3 ; The differential mode power value measured at port II (14) is defined as P DM1-4 , and the common mode power value is defined as P CM1-4 ;

C. The phase definition is defined as φ DMn-m, φ CMn-m according to the power definition method; where nm is the port number;

D. The conducted noise separator 1 separates the differential mode components of the input signals at the input port I (11) and the input port II (12) to the output port I (13) separately, and separates the common mode components to the output port II (14) separately, The following results are obtained: P DM1-3 (dB)=P DM1-1 (dB)-IL DM (dB), P CM1-4 (dB)=P CM1-1 (dB)-IL CM (dB); namely: IL DM (dB)=P DM1-1 (dB)-P DM1-3 (dB),IL CM (dB)=P CM1-1 (dB)-P DM1-4 (dB);

E. If an ideal common mode signal is injected into input port I (11) and input port II (12), there are P CM1-1 = P CM1-2 , φ DM1-1 = φ DM1-2 , P DM1- 1 =P DM1-2 =0; in the same way, if an ideal differential mode signal is injected into the input port I(11)11 and the input port II12 port, then there is P DM1-1 =P DM1-2 , φ DM1-1 - φ DM1-2 =180°P CM1-1 =P CM1-2 =0;

F. Test the common mode insertion loss of the conducted noise separator: the network analyzer (5) generates a test signal from the output port within the set test frequency range, and is decomposed into two equal amplitudes by the in-phase power divider (2). The standard common mode signal with a phase difference of 0° is injected into the input port I (11) and input port II (12) of the conducted noise separator through the output port III (21) and output port IV (22). At the other end of the device, measure the common mode output signal of output port II (14);

According to the characteristics of the noise separator, its calculation formula is: IL CM (dB)=S cc21_measured (dB)-S 13_splitter (dB); wherein, S cc_measured is the S 21 value of the dual-port network analyzer; S 13_splitter is the in-phase power distribution S parameters of the input port and output port of the device, ideally, S 13_splitter =S 23_splitter =3dB;

G. Test the common mode-differential mode isolation of the conducted noise separator. The signal injection method is the same as step F, but at the other end of the noise separator, the differential mode output signal of the output port I (13) needs to be measured;

Since the injected noise source is an ideal common-mode signal and has no differential-mode component, the theoretical value of the signal strength measured at the differential-mode port is 0, and the common-mode-differential-mode isolation is defined as S cd21_real , under ideal conditions, S cd21_real =∞ . But in fact, due to the influence of uncontrollable factors such as impedance matching accuracy and parasitic parameters of components, the results cannot reach the theoretical value. In practical applications, it can be considered that S cd21_real ≥ 30db is the acceptance condition;

H. To test the differential mode insertion loss of the conducted noise separator, the network analyzer (5) generates a test signal from the output port within the set test frequency range, and is decomposed into two equal amplitudes by the inverting power divider (2). , the standard differential mode signal with a phase difference of 180° is injected into the input port I (11) and input port II (12) of the conducted noise separator through the output port V (31) and output port VI (32), and the noise is separated. At the other end of the device, measure the differential mode output signal of output port I (13).