37-傅里葉變換的基本性質(zhì)-文庫吧資料
2024-08-07 16:10本頁面
【正文】 22tEtEtEdt tfd ???????? ?????)4(2)4(s i n8)( 222 ???????? SaEEF ??。4)2(2)]2([ ??? FjFd djttfFT ??)]2([),()]([)1(293179 ttfFTFtfFTP 求設(shè) ???35 ??ddFjttfFT )()]([ ?)2(39。[???????????? jjjjjtFT ????? )()()](1[)()](39。1 二、線性（疊加性） 為常數(shù)iniiiniiiiiaFatfaFTniFtfFT???????11)(])([),2,1()()]([???)(tf2?2?? ???12t求： )(tf 的傅里葉變換 傅里葉變換的基本性質(zhì) 2 )]()([)]2()2([)( ???? ???????? tututututf)2()]([ ???? SaEtEGFT ??)(tf2?2?? ???12t)(2)2()( ??????? SaSaF ??????2?)(?F??2???33 三、奇偶虛實性 )()(a r c t a n)()()()( 22???????RXXRF ???)()()()()]([)()( ???????jXReFdtetftfFTFjtj????? ?????4 f(t)是實函數(shù) ?? ?????? ??? t d ttfXt d ttfR ???? s i n)()(c o s)()()()(s i n)(c o s)()()]([)(??????jXRt d ttfjt d ttfdtetftfFTFtj???????????????????)()()()()()()()(????????????????????FFXXRR5 ??????? a r c t a n)(1)(22????F0)()( ?? ? ?? tuetf t??? jF ??1)(22)( ???????? jF2222 )()( ????????????? XR6 也是實偶函數(shù)是實偶函數(shù)若 )(,)( ?Ftf??????????????0c o s)(2)(s i n)(c o s)()(t d ttfRt d ttfjt d ttfF?????)2()]([ ???? SaEtGFT ??則為虛奇函數(shù)是實奇函數(shù)若 )(,)( ?Ftf???????????????0s i n)(2)(s i n)(c o s)()(t d ttfjjXt d ttfjt d ttfF??????jtFT2)][ s g n ( ?7 f(t)是虛函數(shù) 為實函數(shù)令 )()()(: tgtjgtf ?? ??? ??? dtetftfFTF tj?? )()]([)()()()c o s ()()s i n ()()]s i n ()) [ c o s (()()(??????? ?jXRdtttgjdtttgdttjttjgdtetjgF tj????????????????????????)()()()()()()()(????????????????????FFXXRR8 四、尺度變換特性 為非零實常數(shù)則設(shè) aaFaatfFTFtfFT )(1)
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鄂ICP備17016276號-1