TA的每日心情 | 开心 2023-6-2 15:15 |
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签到天数: 1 天 [LV.1]初来乍到
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wp=0.2*pi;ws=0.3*pi;%你没有给出指标,可以自己改) b: i; z2 V4 t( D" k
Fs=20000;T=1/Fs;%采样频率可以自己定( g" h( Q& [- d: J/ v: L2 x b8 N
OmegaP=(2/T)*tan(wp/2);0 D5 K1 Q0 G' K( \$ T/ G, x3 f+ J, G
OmegaS=(2/T)*tan(ws/2);
3 r2 d0 T, x1 X2 ?' h' ^+ grp=1;rs=15;" a0 _6 D+ D7 x+ U! |
ripple=10^(-rp/20);attn=10^(-rs/20);: `& @4 H6 i* Z; H2 J+ L+ O* G
[n,wn]=buttord(OmegaP,OmegaS,rp,rs,'s');8 S( z; F$ j6 j0 C0 s
[z,p,k]=Buttap(n);! ~3 ~3 m5 l/ V) |* ^- r* V# J
[b,a]=zp2tf(z,p,k);
' W7 c q7 E- @, v% B/ c7 j[bt,at]=lp2lp(b,a,wn);9 h* {6 m! v: R- v1 W0 s+ f
[b,a]=bilinear(bt,at,Fs);
0 f( R) ]4 _8 |6 ~' y0 Z7 l$ l[db,mag,pha,grd,w]=freqz_m(b,a);
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%下面绘出各条曲线4 D; s& H) V6 v1 ^% Q u
subplot(2,2,1);plot(w/pi,mag);title('幅频特性');
2 N2 m! O1 G& mxlabel('w(/pi)');ylabel('|H(jw)|');) C7 b6 U0 y* [ R
axis([0,1,0,1.1]);, i$ e7 q7 _- @" J4 o V8 H
set(gca,'XTickMode','manual','XTick',[0 0.2 0.3 1]);4 P/ @/ {. n1 ^2 F9 f* J/ a5 t
set(gca,'YTickMode','manual','YTick',[0 attn ripple 1]);grid' H( z) v4 n a2 p9 V- m
subplot(2,2,2);plot(w/pi,db);title('幅频特性(db)');7 A3 O9 `# Y$ q* k- h" K
xlabel('w(/pi)');ylabel('dB');+ }) T( ]( i: [, S5 ]0 q
axis([0,1,-30,5]);0 C: r+ L: Q. f0 ]' G
set(gca,'XTickMode','manual','XTick',[0 0.2 0.3 1]);9 ?6 |& N0 V7 s/ r6 S: r
set(gca,'YTickMode','manual','YTick',[-60 -as -rp 0]);grid
# p5 d4 A, S. g( nsubplot(2,2,3);plot(w/pi,pha/pi);title('相频特性');
4 N$ p/ f3 C6 ~' U/ |& Axlabel('w(/pi)');ylabel('pha(/pi)');
' v/ `- h5 T" X# @5 \7 Eaxis([0,1,-1,1]);
: c* @0 A+ m1 P# X) F% }8 Tset(gca,'XTickMode','manual','XTick',[0 0.2 0.3 1]);grid
3 Y0 [7 B) p3 Y0 r. tsubplot(2,2,4);plot(w/pi,grd);title('群延时');
2 U5 b5 d1 O7 C' mxlabel('w(/pi)');ylabel('Sample');! a i% ~) I, G! G9 V
axis([0,1,0,15]);/ Y2 F9 }$ i; p# \6 m
set(gca,'XTickMode','manual','XTick',[0 0.2 0.3 1]);grid
" G, B( y- M$ c6 B0 F! a# |%b,a是滤波器的系数,系统函数根据b和a写出。
* {( L3 t- Z" [%若程序运行有问题可以Hi我: h# `7 c. O+ B
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