frequency_band_transformation.m

来自「很多matlab的源代码」· M 代码 · 共 46 行

h0=figure('position',[10 10 800 500],...
    'name','频带变换');
wplp = 0.2*pi;
wslp = 0.3*pi;
Rp = 1;
As = 15;
T = 1;
Fs = 1/T;
OmegaP = (2/T)*tan(wplp/2);
OmegaS = (2/T)*tan(wslp/2);
[cs,ds] = afd_chb1(OmegaP,OmegaS,Rp,As)
[blp,alp] = bilinear(cs,ds,Fs);
[db,mag,pha,grd,w] = freqz_m(blp,alp);
subplot(2,2,1);
plot(w/pi,mag);grid
xlabel('w');
ylabel('|H|');
subplot(2,2,2);
plot(w/pi,db);grid
xlabel('w');
ylabel('dB');
axis([0 1 -30 0]);
wphp = 0.6*pi;
alpha = -0.3820;
Nz = -[alpha,1];
Dz = [1,alpha];
[bhp,ahp] = zmapping(blp,alp,Nz,Dz);
[db,mag,pha,grd,w] = freqz_m(bhp,ahp);
subplot(2,2,3);
plot(w/pi,mag);grid
xlabel('w');
xlabel('|H|');
subplot(2,2,4);
plot(w/pi,db);grid
xlabel('w');
ylabel('dB');
axis([0 1 -30 0])
[C,B,A] = dir2cas(bhp,ahp)
Hc_close=uicontrol(gcf,'style','push',...
   'position',[730 80 50 25],...
   'string','Close',...
   'Callback','close');
Hc_info=uicontrol(gcf,'style','push',...
'position',[730 110 50 25],...         
'string','info',...                 
'Callback','web http://www.bupt.edu.cn -browser');