精品課程大學(xué)物理-系統(tǒng)頻域分析應(yīng)用舉例(編輯修改稿)
2025-08-18 06:11 本頁(yè)面
【文章內(nèi)容簡(jiǎn)介】 ]21()21([2)( 11由抽樣信號(hào)頻譜及 Fourier變換的時(shí)域和頻域位移特性可得 ?????? ???????? ???? )(2 1c o s)(2 1Sa2 1)( c dcdc ttttty ???三 .調(diào)制與解調(diào) 1． 雙邊帶調(diào)幅 (Amplitute Modulation)信號(hào) 幅度調(diào)制框圖tc?cos)( tf )( ty?調(diào)幅信號(hào)解調(diào)框圖tc?cos)( tr)( tyc?c??1?)( ?H)( tfrt0co s?ttgA 0co s)]([ ??A+g(t) ttg 0c o s)( ?)(tgA?調(diào)制過(guò)程頻譜的變化 )( ?Y?2/Ac?c??上邊帶 下邊帶上邊帶 下邊帶)(?F?Am??)(?Y ?2/A c?c?? )( ?C ?)( ? c?c?? )( ??解調(diào)過(guò)程頻譜的變化 )(?Y?2/Ac?c??上邊帶 下邊帶上邊帶 下邊帶)( cY ?? ??2/Ac?2? m? m?? )( cY ?? ??2/A c?2m?m? )(?R ?2/A c?2c?2? m? m?)(?rF?m??A2單邊帶調(diào)幅信號(hào)的頻譜分析 單邊帶調(diào)制框圖tc?cos)( tf)( tyc?c??1?)( ?H)( tys)(?F?Am?m??)( ?sY?2/Ac?c??調(diào)幅信號(hào)解調(diào)框圖tc?cos)( tr)( tys ? )( tf rc?c??1?)( ?H單邊帶幅度調(diào)制 )(?Y ?2/A c?c??上 邊 帶 下 邊 帶上 邊 帶 下 邊 帶 )(?dnY 2/A c?c?? )(?upY 2/A c?c??)(?F?Am??單邊帶幅度調(diào)制已調(diào)信號(hào)的解調(diào) )(?R ?4/A c?2c?2? m? m?)(?rF?2/A m??)(?dnY 2/A c?c??3． 頻分復(fù)用（ FDM FrequencyDivision Multiplexing ） ) ( 1 ? F ? 0 ) ( 2 ? F ? 0 ) ( 3 ? F ? 0 ?1cosc?2cosc?3cosc?)(1tf)(2tf)(3tf)( ty)( ?Y?02c?1c? 3c? 時(shí)分復(fù)用 x1( t )x2( t )x3( t )y ( t )p ( t )1p ( t )2p ( t )3y1( t )y2( t )y3( t )原理框圖 時(shí)分復(fù)用時(shí)的周期脈沖信號(hào) . . .. . .tT 2 T 3 Tp ( t )0. . .. . .T 2 T 3 Tp ( t )1t0. . .. . .T 2 T 3 Tp ( t )2t0
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