精品課程大學(xué)物理-非周期信號(hào)的分解(參考版)
2024-08-02 06:12本頁(yè)面
【正文】 The system frequency field analysis methods ? System’s analysis in frequency )( wjH)( wjF )( wjY)(tf )(ty)()()(wwwjFjYjH =)]([)( thFTjH =www jppHjH == )()(?=???=?niti tektAtAthi1039。2 w?? j=t ? ??)s g n ( tt =ww jd dj 2 22w}1)({)]([ww??w?jddjttFT ?=21)(39。s derivative ?????=)(0)()1()(222ttttttEtf? ?)(2)()(2)( 2222 tttEdttfd ???ttt ??=)4(24s i n8)2(2)()(2222 22wttwwtttwwtt wwSaEEeeEjFjjj=??????=?=)4(2)( 2 wttw SaEjF =FT )(tf2t2t 0tdttdf )(tE2tE22t2ttE2tE2tE42t2t)( wjFtE2t?4t?422 )(dttfdtt000 triangle impulse Integration ? If ? then 0)0( ?F)()0()()( w??wwtt FjjFdfFT t ?=?????? ??)()( wjFtf ? ??=??])([ t dfFTs o l u t i o n tt： )]()([ ttfFT ??)]([)]([ tFTtfFT ??=]1)([)(ww??wjjF ??=)(1)()0( www?? jFjF ?=l e t f 39。如圖，求且 )()( tfR w )(wR11w1 0 解： )()()( 2 ww PRtf e =?tttfe ?s i n)( =?)()(2)( ttftf e ?=而因果信號(hào))(s i n2)( ttttf ??=? TRANSFORM OF COMMON SIGNALS ? Real exponential signals ? Sign signals ? Rectangle signals ? Unit impulse signals ? Direct current ? Unit step signals ? imaginary exponential signals 1. Real exponential signals 221)(ww?=aF)0()()()1( ?= atetf at ?dtetfjF tj? ??= ww )()(dtee tjat?? =0wwja ?= 1magnitude： phase： )(t a n)( 1 aww? = f(t) t 0 )(wF?1?21a3w)(w?w0 0 2?2?)0()()()2( ?= atetf at ?dtetfjF tj? ??= ww )()( dtee tjat??= 0 wwja = 1221)(ww?=aFphase： )(t a n)( 1 aww? =magnitude： )()()3( ?????= tetf t?dtedtejF tjatja ???? ?? ?=0)(0 )()( 0)( =w? f(t) )(wFw0 t 0 222w?=aaww jaja ??= 11??????==)0(1)0(1)s gn ()(ttttf]).[ s g n (lim)(lim)(010taaaettftf ??==wwjajjFjFaa22l i m)(l i m)(22022 =?==??ww2)( =jF??????=)0()0()(22www???2. Sign signals f1(t) )(1 wjF1 0 t a a 0 t Sgn(t) +1 1 )( wjF)(w?2?2?wwtae0?a)2()2()( t?t?t ?= tttP)2(2)2s i n ()2s i n ()( 22/2/wttwtwttwtwwttwSadtejFtj=????????????=== ?)()( 2wttw SajF =?????????= ???)()(0)( )1(4)12(2)12(24t?t?t?t?w?ww? nnnn3. Rectangle signals t 0 )( wjFt?2t?4
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