【正文】
???????????????]2[c os1s i n)(|2c os|2s i n)c os1(|)(|s i nc os1)()(1)()1()2()2~0()()()(|)(|)1()()(|)(|)()1()()(13221)()(wtgar c t gwwar c t gwwwweHwjwzHeHzzHwwHeHewHeHF I ReeHeHnnnhjwezjwjwwjjwwjjwjwjw????????解:說明它們的區(qū)別。曲線連貫,可正可負(fù),為正數(shù),)()(|)(|)()(|)(|)2(wweHwHwHeH jwjw????315204312010325432105432100)(0)(0)()()()()()()()()(14NNNNNNNNnNNNmnNmnhNmNmxnymnhmxnhnxnyNNNNNNNnNnyNnNnxNnNnhm????????????????????????????????????????;解:。第四類線性相位為偶數(shù)奇對稱,解:4)(210)2(0)0()21s i n (12)23s i n (6)25s i n (2)()]21s i n (12)23s i n (6)25s i n (2[36631)()()3()5()4(3)3(6)2(6)1(3)()(36631)()2(6)()1()252(543254321??????????????????????????????????????????????????????HHHwHeeeeeezHeHnxnxnxnxnxnxnyzzzzzzHDRF I RNnhwjjwjwjwjwjwezjwjw,曲線如下:相位函數(shù) ww 252)()4( ?? ??2??205? ?w)(w?寫系統(tǒng)函數(shù)。運(yùn)算,如何完成上述計點(diǎn)若一次只能進(jìn)行處的頻響?來計算,如何才能得到用說明:頻率處的頻率特性,請值,現(xiàn)需測量它在時的數(shù),觀察得到,、知序列D F TND F TMkSHzkfTkNwND F TnTsfTwHzfD F TD F THznsTnTsk5121024)2()(625402210241000)(2625)1(512)2(625)1(625999...)(1740???????????????????。至少取基至少取基長長,長,82235225133)(3)(3)()2(40}381483{)()()(321???????????????????FFTMFFTNnwNnbNnaNnbnanwMjzzjzzkezzzzzzHzzzHkjk22223210216111611611161)()1()3()2()1(1611161)(1904030201420444444??????????????????????????,,零點(diǎn)解:證明系統(tǒng)是全通系統(tǒng)。求,系是:的關(guān)與,另一個序列、已知序列:)1()2()()1(101821432121平面零極點(diǎn)位臵圖解:。圖,轉(zhuǎn)折頻率大致是幅頻特性的大致形狀如323)2())(()1())()()(()1)(1()(212122323233?????????????????????????????zzzzzzezezezezzzzHjjjj3?32??w3???? ?32?|)(| jweH0)()()()()()]([)()]([)()()()()(1jwjwmj m wmnnj n wnj n wjwjwjweXnxeXemxenxnxD T F TenxnxD T F TeXeXnxeXnx????????????????????????? ?????????????證:,則、證明:若三、證明題 ???????????? ????????????????????????虛部奇對稱實(shí)部奇對稱為奇對稱證:為純虛數(shù)且奇對稱。虛部偶對稱實(shí)部奇對稱虛部偶對稱實(shí)部偶對稱為虛部偶對稱實(shí)部奇對稱為共軛奇對稱為純虛數(shù)??????????????????????????????????????)()()(*)(**])([)(*)()()(*)()(101010kXkXkNXkXWnxWnxWnxkXnxnxnxNnnkNNnnkNNnnkN?)0(... ... ..00)0()(lim0)(lim|)(|... ... .])2()1()0([lim)(lim... ... .)2()1()0()()()0()(lim)()(|)(|)(421210xxzXznxMnxzxzxxzXzxzxxznxzXxzXzXnxMnxnxznzzznnz??????????????????????????????????????????證:。倒數(shù)的濾波器的零點(diǎn)必是互為、證明:線性相位*)(*)(*)(*)(0)(00)()()()()1()(51010001001010010)1(0001)1(??????????????????????????????iiiiiiiiiiNiiiNzzzzzzzzHzF I RzHzzHzzHzzHnNhnhF I R?系統(tǒng)變成因果系統(tǒng)。應(yīng)序列之和等于濾波器,它們的脈沖響的理想低通和理想高通頻率、證明:具有同樣截止)()s i n ()()()()s i n ()s i n ()(21)()s i n (21)(nnnnhnhnhnnwnndwedwenhnnwdwenhdHdLcwj w nwj w ndHcwwj w ndLccccc??????????????????????????