TA的每日心情 | 开心 2023-6-2 15:15 |
---|
签到天数: 1 天 [LV.1]初来乍到
|
wp=0.2*pi;ws=0.3*pi;%你没有给出指标,可以自己改: c& s- Q1 |3 W
Fs=20000;T=1/Fs;%采样频率可以自己定6 @/ S4 d1 ]* {! A: T9 J
OmegaP=(2/T)*tan(wp/2);" b+ X5 A4 [6 U. L0 D4 @* a
OmegaS=(2/T)*tan(ws/2);+ N6 v% w% Y" W" U
rp=1;rs=15;
# u o9 F+ |7 B, v: B4 A( Cripple=10^(-rp/20);attn=10^(-rs/20);" K$ s0 H8 l0 K
[n,wn]=buttord(OmegaP,OmegaS,rp,rs,'s');
! \; v7 t- X0 I3 D# ]5 j[z,p,k]=Buttap(n);
, S c+ v5 u5 C) W( P7 i& t7 M[b,a]=zp2tf(z,p,k);
" P# m& v" @4 ?/ m& C[bt,at]=lp2lp(b,a,wn);8 g* I6 W+ c$ _0 e" T# `
[b,a]=bilinear(bt,at,Fs);* X; @4 ]' L4 K' Z% i: o& Q
[db,mag,pha,grd,w]=freqz_m(b,a);& }- g4 r5 T- b8 V) G7 f' N7 x
%
5 W5 l3 h0 A6 ]3 t& a) V1 U%下面绘出各条曲线, F T- J0 b4 X1 P/ m
subplot(2,2,1);plot(w/pi,mag);title('幅频特性');4 N) l. d+ s$ F& B$ l0 \/ x8 a3 e' T
xlabel('w(/pi)');ylabel('|H(jw)|');8 ?8 b* J1 v. u% G! G' }* x
axis([0,1,0,1.1]);
1 p! C" U2 e; Hset(gca,'XTickMode','manual','XTick',[0 0.2 0.3 1]);3 ]. K/ e" ~. J% r& ?2 K# T; O- W
set(gca,'YTickMode','manual','YTick',[0 attn ripple 1]);grid7 T. R% x! ?, |) |# B; ^6 I
subplot(2,2,2);plot(w/pi,db);title('幅频特性(db)');
* k% H3 D5 T# Y8 axlabel('w(/pi)');ylabel('dB');
7 Z$ L2 w2 U. t( T7 A1 Kaxis([0,1,-30,5]);
( K& P) x+ u! O2 r3 f, l. ]set(gca,'XTickMode','manual','XTick',[0 0.2 0.3 1]);2 Q- n0 }% j* g% K1 G4 S
set(gca,'YTickMode','manual','YTick',[-60 -as -rp 0]);grid
+ T& w) D" Q2 S% y3 f/ d* osubplot(2,2,3);plot(w/pi,pha/pi);title('相频特性');
( h X% ?! y) exlabel('w(/pi)');ylabel('pha(/pi)');- X4 c/ \% v& H: x
axis([0,1,-1,1]);" T& }1 A+ V' S8 }7 W
set(gca,'XTickMode','manual','XTick',[0 0.2 0.3 1]);grid4 d9 y" Z7 Y# e& ?2 G) d% n' s
subplot(2,2,4);plot(w/pi,grd);title('群延时');
: ]* A4 [) ?! k. qxlabel('w(/pi)');ylabel('Sample');
9 [- H s+ p. naxis([0,1,0,15]);0 r8 W( ?% O& |
set(gca,'XTickMode','manual','XTick',[0 0.2 0.3 1]);grid
8 g2 y7 _4 V# x* ^: N%b,a是滤波器的系数,系统函数根据b和a写出。- J6 p! F6 }- l8 L2 ]9 X" L
%若程序运行有问题可以Hi我8 u( A7 @; o% Y7 B2 [/ l
|
|