同軸電纜轉移阻抗測量方法

Ⅰ 請高手幫忙翻譯

屏蔽效率測量
Measurement of Shielding Effectiveness
屏蔽效率是評價射頻電纜屏蔽性能的重要參數，屬於電磁兼容的范疇。近年來，隨著歐盟CE強制安全認證的開展、,電纜的屏蔽效率越來越受到人們的關注判鬧。
Shielding effectiveness is an important parameter for evaluating Radio-Frequency coaxial cable's shielding performance, belonging to the category of EMC. Recently with the concting of mandatory CE certification in European Union, the shielding effectiveness is paid more and more attentions.
屏蔽效率主要有以下幾種測量清圓方法：三同軸法、吸收鉗法、線注入法、GTEM Cell小室法。其中三同軸法可以測掘正罩量電纜的轉移阻抗、耦合損耗、屏蔽衰減等；吸收鉗法可以測量電纜的屏蔽衰減；線注入法可以測量電纜的耦合損耗；GTEM Cell可以測量電纜的屏蔽衰減。
The commonly used methods to measure shielding effectiveness of RF coaxial cable are triaxial method, absorbing clamp method, wire injection method, and GTEM cell method. Of which triaxial method can be used to measure the transfer impedance, coupling loss, screening attenuation, etc. of cables; absorbing clamp method can be used to measure the screening attenuation of cables; wire injection method can be used t measure the coupling loss of cables; and GTEM cell method can be used to measure the screening attenuation of cables.
屏蔽效率的幾個參數定義如下：
The definitions for the parameters about shielding effectiveness are as follows:
1．屏蔽衰減定義為沿電纜屏蔽層單位長度測得的電壓與內導體通過的電流之比。
1. Screening attenuation is defined as the ratio of the voltage measured along the unit length of cable shield layer to the current passing through the inner conctor.
2．耦合損耗定義為線纜的輸入功率與遠端或和近端耦合功率較大值的對數比（對於同軸電纜，其等於屏蔽衰減）。
2. Coupling loss is defined as the logarithmic ratio of the input power of the cable to the coupling power, which got the maximum effect of either near or far end. (for coaxial cables, it equals to screening attenuation).
3．屏蔽衰減定義為線纜的輸入功率與最大輻射功率的對數比,可以被認為是一個電氣長度比較長的電纜的屏蔽效率。
3. Screening attenuation is defined as the logarithmic ratio of the input power of the cable to the radiated maximum peak power, it can also be considered as a electrically long cable's shielding effectiveness.

Ⅱ 求qindajia幫忙翻譯

表面轉移阻抗（三同軸檔喊法）測量
目前，對於屏蔽對稱電纜和屏蔽多芯等類似於同軸電纜的表面轉移阻抗測量國內還未有標准，IEC 62153-4-3:2002 電磁兼容——表面轉移阻抗（三同軸測量方法）及EN 50289-1-6:2002 轉移阻抗（三同軸測量方法）是一種既可以測量同軸電纜又可以測量類同軸的屏蔽對稱和屏蔽多芯電纜的轉移阻抗試驗方法。IEC 62153-4-3:2002有測試方法A（匹配-短路法）和測試方法B（短路-短路法）兩種，其中測試方法A與EN 50289-1-6:2002測量方法完全相同。本文介塵飢紹的是IEC 62153-4-3:2002測試方法A的內容。該方法在100MHz頻率以下測量無須在屏蔽室內進行，且測量較為方便。
1．轉移阻抗ZT的定義
一個短電氣長度的縱向均衡屏蔽的轉移阻抗ZT定義為單位長度上由被測的屏蔽及測量夾具形成的，在匹派蠢返配外電路上感應的縱向電壓U2和饋入內電路的電流I1之比。反之亦然。
2．轉移阻抗的測試方法
通過測量在三同軸裝置中的電纜來測定電纜的轉移阻抗。試樣電纜的屏蔽和內導體組成內電路，電纜屏蔽和同軸測試夾具組成外電路，且內電路即電纜終端是匹配的，外電路的近端即電纜屏蔽的近端是短路的，遠端連接到接收機。
Surface transfer impedance (3 coaxial) measuring
At present, the shielded cable and shielded symmetrical multi-core and other similar surface transfer impedance of coaxial cable not a standard measure of domestic, IEC 62153-4-3:2002 Electromagnetic Compatibility - Surface transfer impedance (three coaxial measurement method) and EN 50289-1-6:2002 transfer impedance (3 coaxial measurement method) is a measurement of both coaxial cable and can measure type coaxial shielded symmetrical and shielded multi-core cable transfer impedance test method. IEC 62153-4-3:2002 a test method A (match - short-circuit method) and test method B (short - short-circuit method), with which test methods A and EN 50289-1-6:2002 exactly the same measurement methods. This article describes the test method A, IEC 62153-4-3:2002 content. This method is not measured in the 100MHz frequency of the following conct in a shielded room, and the measurement is more convenient.
1. The definition of transfer impedance ZT
A short length of the longitudinal electric shield transfer impedance ZT balanced is defined as the unit of length measurement by the DUT fixture shielding and the formation, the way in matching foreign longitudinal voltage sensor and fed into the U2-circuit ratio of the current I1. And vice versa.
2. Transfer impedance test method
By measuring the device in three coaxial cables to determine the transfer impedance of cables. Sample cable shield and inner conctor within the circuit component, coaxial cable shield and the composition of the external circuit test fixture, and the cable terminal is within the circuit that matches the external circuit that is proximal to the proximal shield cable is short, and remote connected to the receiver.

Ⅲ 電纜屏蔽效率db是什麼

屏蔽性能指標介紹

1.表面轉移阻抗(SuRFaceTransferImpedance)

按IEC61196-1測試同軸電纜的方法，測試帶屏蔽的平衡電纜，短路8根芯線後用50Ω信號源激勵。被測試線長1米，測試頻率30MHz，頻率越高，線長越短導體表面轉移阻抗。主要用於評估連接硬體的屏蔽效率，其實測值不超過以下計算值。

ZTcable=37+4f+4f1/2+5f1/3

ZTcable：表面轉移阻抗，單位mΩ/m f：信號頻率，單位MHz

2.轉移阻抗(TransferImpedance)

轉移阻抗與屏蔽電纜和連接硬體的屏蔽效率相關，其數值可通過實驗室高頻密封箱測量屏蔽插入損耗，計算得出。

屏蔽性能指標介紹

1.表面轉移阻抗(SuRFaceTransferImpedance)

按IEC61196-1測試同軸電纜的方法，測試帶屏蔽的平衡電纜，短路8根芯線後用50Ω信號源激勵。被測試線長1米，測試頻率30MHz，頻率越高，線長越短導體表面轉移阻抗。主要用於評估連接硬體的屏蔽效率，其實測值不超過以下計算值。

ZTcable=37+4f+4f1/2+5f1/3

ZTcable：表面轉移阻抗，單位mΩ/m f：信號頻率，單位MHz

2.轉移阻抗(TransferImpedance)

轉移阻抗與屏蔽電纜和連大豎接硬體的屏蔽效率相關，其數值可通過實驗室高頻密封箱測量屏蔽插入損耗，計算得出。

Ri1=Ri2=50Ω——網路分析儀特性阻抗 R1=50Ω——饋電電阻 R2=50Ω——終端電阻 U1=信號發射電壓(V) U2=信滾謹大號接收電壓(V) Uc=被測設備兩端電壓 Zcond=連接器特性阻抗(Ω) Zt=轉移阻抗(Ω)

Zt=1/l電纜長度•Ri1/Ri2•(R2+Ri2)•U2/U1=100/l電纜長度•U2/U1 由於屏蔽插入損耗(αs)為20•lg(U2/U1)dB，轉移阻抗(Zt)也可以表示為： Zt=100•10α/20(Ω)

3.耦合衰減(CouplingAttenuation)

耦合衰減用於描述電纜系統的電磁兼容性能。耦合衰減Catt=Pr/Pi(Pr：線纜接收功率;Pi：在內導體上產生的雜訊功率)

將電纜近似看作電磁場中的全向天線，其接收到的電磁功晌鍵率Pr=λ2/4π•PD(λ：信號波長，PD：電磁場功率密度) .

Ⅳ 同軸電纜阻抗如何測量

用DTX－1800的測試儀器，在基準中選中同軸電纜就進行測試，然後查看一下標准就好了。

Ⅳ 什麼是轉移阻抗啊,為什麼說同軸電纜可以提供一個最大的電纜轉移阻抗

在復雜電力系統中只保留發電機電動勢節點（包含無限大功率母線）和短路點，經過網路化簡消去其他中間世弊節點（或稱聯絡節點），最後得到一個網路。在此網路中，可以略去各電源間的搜租族連線，以為連線中的電流是電源間的交換電流，與短路電流無關。這樣就形成了一個以短路點為中心的輻射形網路，每一條輻射支路只含一個電源，經一阻抗（稱轉移阻抗）與短路點相連。 簡單的說，電源的轉移阻抗就型頃是電源到電路短路點阻抗，多用於短路計算。

Ⅵ 如何用同軸電纜本身的性質計算特性阻抗

然而在計算機網路中，「寬頻電纜」卻指任何使用模擬信號進行傳輸明判的電纜網。 (1)同軸電纜的特搏凱性阻抗 同軸電纜的平均特性阻基槐喚抗為50±2Ω,沿單根同軸電纜的