一簡潔電路實現差模等化器及共模濾波器

A Neat Circuit Realizing Differential-Mode Equalizer and Common-Mode Filter

邱繼群(Chi-Chun Chiu)

指導教授 ： 邱奕鵬

國立臺灣大學/電機資訊學院/電信工程學研究所/碩士(2017年)

https://doi.org/10.6342/NTU201701276

摘要

隨著處理器的時脈提昇至GHz頻率，資料傳輸速率達到Gbit/s時，許多過去低速不需考慮的問題，在高速訊號傳輸系統當中這些問題已經嚴重影響到訊號的傳輸，良好的差模訊號及有效的抑制共模雜訊在高速訊號傳輸系統占有非常重要的因素，缺一不可，有這兩個因素才可使系統保有良好的訊號完整性。
本論文提出有別於傳統被動等化器只有均衡的效果，由左右兩側高阻抗線中間為低阻抗線接上電阻所組成的結構，不但具有均衡還有寬頻共模濾波器的效果。主要是利用差動對在共模中間斷路特性達成共模濾波器功能；而差動對在差模中間短路特性，使電阻接地來衰減低頻訊號達到均衡的效果。本論文將針對電路結構參數變化做分析，進一步提出等效模型與實驗及模擬做比較，此外，在量測當中可以看出對於共模雜訊有很好的抑制效果，而在差模傳輸當中，本來已關閉的眼圖，獲得了顯著的改良而重新開啟已關閉的眼圖。

關鍵字

訊號完整性 ； 被動等化器 ； 共模濾波器 ； 符碼間干擾 ； 電磁干擾 ； 高速差動訊號傳輸

並列摘要

With the clock rate of the CPU increasing to the GHz frequency level, problems that are not very critical in the past become more serious in the high-speed (Gbit/s) data/signal transmission systems. Good differential signal and effective suppression of common mode noise are two vital factors in the high-speed signal transmission system to maintain high quality signal integrity.

The aim of this thesis is to propose a structure composed of a low impedance line connected with resistors between two high impedance lines to achieve the function of equalizer and common mode filter, which is different from conventional passive equalizer with only equalization function. The fundamental of this structure is mainly based on the intermediate open circuit properties in the differential line to achieve the common mode filter function. Meanwhile, due to the intermediate short circuit characteristic, the resistor can be grounded to suppress low frequency signal can achieve equalization effect. In addition, the circuit structures with different parameters are analyzed and equivalent models are proposed to compare with experimental and simulation results. In the measurement, the proposed structure exhibits excellent common mode noise suppression behavior. Under differential mode transmission, the intrinsically closed eye diagram is significantly improved and can be re-open.

並列關鍵字

signal integrity ； passive equalizer ； common mode filter ； inter-symbol interference ； electromagnetic interference ； high speed differential signal transmission

參考文獻

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