高清晰度多媒體介面HDMI(High Definition Multimedia Interface)在目前3C 產品逐漸普及化，幾乎在Notebook、Ultra book、all-in-one PC (AIO)、Tablet PC甚至手機也可能有HDMI Port，這樣複雜的系統中HDMI訊號在印刷電路板(Printed circuit board, PCB)的電磁輻射干擾（Electromagnetic Interference, EMI）問題，一直是EMC (Electromagnetic Compatibility, EMC)工程師解決電磁輻射干擾EMI最為困擾的問題。本論文實驗針對印刷電路板HDMI訊號線貫穿導孔的佈局，分析EMI的影響與差異，同時也對訊號線的阻抗匹配做比較分析。 本論文在all-in-one PC的印刷電路板中佈局兩個版本，比較當HDMI訊號走線在印刷電路板六層板中通過4個vias（貫穿導孔）與2個vias（貫穿導孔）的EMI差異。運用頻譜分析儀近場量測觀察EMI的輻射強度，再用3米的無反射電波暗室量測4 vias與2 vias的EMI差異，量測頻率為30MHz~1GHz。實驗中另外也運用時域反射儀量測HDMI訊號線的阻抗匹配，分析EMI輻射強度與線路阻抗匹配之間的關係。 The High-Definition Multimedia Interface (HDMI) becomes more and more common in current 3C products, such as Notebook, Ultra book, all-in-one PC (AIO), Tablet PC. Even a mobile phone may have HDMI Port. In such a complex system, the electromagnetic interference (EMI) of HDMI signal on printed circuit board (PCB) is always one of the difficult issues for an EMC engineer. This thesis focus on the layout of through vias of HDMI signal routing which analyzes the impacts of EMI and compares differences of EMI and the signal impedance matching. Two different layouts of HDMI signal routing of PCB in an all-in-one PC will be designed for comparing the differences between the HDMI signal routing with four vias (through vias) and signal routing with two vias (through vias) in a 6-layer motherboard. Using spectrum analyzer with near-field measurement to observe the EMI radiation intensity, and then use three meters of non-reflective chamber to measure the differences between 4 vias and 2 vias of EMI in frequency 30MHz to 1GHz. This experiment also uses Time Domain Reflectometer (TDR) to measure the impedance matching of HDMI signal routing and analyze the relationship between the EMI radiation intensity and the impedance matching of signal line.
