探討差模信號相鄰接地防護線與接地平面之共模雜訊產生和抑制方法

Investigation on Common-Mode Noise Generation and Reduction for Differential Traces with Adjacent Ground Lines and Plane

洪晧哲(Hao-Che Hung)

指導教授 ： 薛光華

中原大學/電機資訊學院/通訊工程碩士學位學程/碩士(2015年)

https://doi.org/10.6840/CYCU.2015.00416

摘要

近日由於高速數位訊號的資料傳輸率越來越快，傳送高速數位訊號大多已採用差模訊號(Differential Signals)線結構來傳輸，而多對差模訊號對傳輸更成為現今之趨勢，因此本文主要研究共模雜訊是如何因差模信號與相鄰的接地防護線和接地平面間之串音效應而產生進行討論，設計準則以及抑制方案皆會在本文內提出。
主要分為兩個部分，第一部分為差模信號線相鄰接地防護線連接接地平面結構，第二部分為差模信號線相鄰接地防護線與接地平面結構，本文主要是探討在這樣的結構之下雖可以抑制串音雜訊，但往往也會增加額外的共模雜訊，會針對這兩部分的共模雜訊進行生成原因的分析，以及探討抑制共模雜訊的方法，此外，這兩部分的測試結構將會針對不同的設計情況進行研究，以驗證共模雜訊的產生機制，以及抑制方案。基於分析共模雜訊的生成機制，提出了共模雜訊的抑制方法，在這兩大部分中，分別對共模雜訊有92%與94%峰對峰值的抑制效果，此外，在頻率範圍0GHz〜6GHz的頻域中差模轉共模模態有超過35分貝的抑制效果。

關鍵字

差模信號 ； 接地防護線 ； 接地平面 ； 共模雜訊

並列摘要

This study investigates how common-mode noise (CMN) is generated for the differential traces with adjacent ground lines and plane. Design guidelines and reduction schemes for reducing CMN are proposed. For a clear differentiation, eachtest structure was divided into two parts. In one, differential traces with adjacent ground lines were connected to a ground plane. The other structure is the differential traces adjacent one ground line and ground plane. In the other, differential traces adjacent to one ground line were connected to a ground plane. The CMN generation mechanisms and reduction schemes are studied in the two structures. In addition, the test structure with different designs cases is also investigated to verify the effectiveness of the CMN generation mechanisms and reduction schemes. Based on the analysis of the generation mechanisms and reduction schemes, design guidelines for CMN reduction are proposed. In both reduction schemes, peak-to-peak CMN amplitudes in the time domain were 92% and 94% of those obtained by unsuitable designs, respectively. Moreover, in the frequency domain, the reductions in the magnitude of differential-to-common mode conversion (|Scd21|) at the resonant peaks exceeded 35 dB in the frequency range 0 GHz ~ 6 GHz.

並列關鍵字

Differential Signal ； Ground Lines ； Ground Plane ； Common-Mode Noise

參考文獻

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