多路徑對載波頻率的影響

Abstract

在通訊系統中因通道多路徑衰減(Multipath fading)將會造成符號間干擾。本論文中採用平方時脈恢復(Square Timing Recovery)方法取得正確的時脈，設計過的載波頻率恢復器(Carrier Recovery)子系統作載波頻率錯誤補償，線性最小均方差的等化器(Linear LMS Equalizer)將通道間的符號間干擾消除，可同時處理載波相位補償，使其作信號星座圖收斂的同時也作反相位旋轉。最後以Matlab/Simulink的模擬工具分析通道衰減對時脈以及載波頻率的錯誤影響。

In the communication systems, the channel multipath fading will cause Inter-symbol interference (ISI). In this thesis, the Square Timing Recovery is used to get correct Timing. The design of carrier recovery subsystem is used to compensate the frequency error. However, the convergence of the output constellation from system is not satisfactory. Therefore, we use the Linear Least Mean Square equalizer as last stage to overcome the constellation convergence problem and compensate carrier phase error. Finally, analysis of channel fading on the timing and carrier frequency error effects in Matlab/Simulink simulation toolbox.