r()=- ie(t-to) cOS f io(t-lo) cos o(t-to )do+ cos0. cos o(t-to dda f cos o( - do+ 2r Jo cos @-cos o(-1o do cos o(t-to ) do 4丌 cosOlt-to +-lo+cosa t-to- L Salo (t-lo]+@e saot-Io+r+@e Sao(-1o-7 补充题:设计一个巴特沃什低通滤波器,技术要求如下 LPAF: Q =6k rad/s a=3db Q2=15k rad/s a=35db an=3db∴n=90,n 1010-1 =44,取n=5 Q Q H(92 1人)分=H(AD)H(),S=2,取k=34567, f(2 (2-9,e)/g-9,e3X2-g2e)2-9,e3)g-9e3)( ) ( ) ( ) ( ) ( ) ( ) ( ) ( )  ( )                + − −              = − + − +               + − −         = − + − + = − +  − = − +  − = +         − − − − − − c c c c c c c c c c c c i t t c i t t Sa t t Sa t t Sa t t t t d t t t t d t t d t t d t t d t t d r t e d e d c c c c c c c c c c c c                                                                 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 4 4 cos cos 4 1 cos 2 1 cos cos 2 1 cos 2 1 cos cos 2 1 2 1 cos 2 1 2 1 cos 2 1 2 1 2 1 2 1 0 0 补充题：设计一个巴特沃什低通滤波器，技术要求如下： k rad s db LPAF k rad s db s s p p 15 / 35 : 6 / 3  = =  = =   。   p = 3db p = 0 ， 4.4 lg 10 1 10 1 lg 10 ( ) 10 ( ) =           − − =   s p s p n   ，取 n = 5， ( ) ( ) 1 1 ( ) 2 5 2 =  −            +  =  H j H j H j p ， , 3,4,5,6,7 5 S =  e k = k j k p 取  ， ( )( )( )( )( ) ( ) 5 7 5 6 5 5 5 4 5 3 5      j p j p j p j p j p p j e j e j e j e j e H j − − − − −   =