bpfphase.m

用matlab计算并成图形的电路设计中幅频=相位响应图

clear;clc;
w0=1000;
Q=20;

w=800:5:1200;

    n1=w./w0;
    c1=1./(1+j.*Q.*(n1-1./n1));
    c1_abs=abs(c1);c1_ph=angle(c1);
    a=plot(w/1000,c1_abs,'k');
    set(a,'linewidth',4,'color','r')
    hold on;
     
for dw=0:25:50
    n1=w./(w0-dw);
    n2=w./(w0+dw);
    c2=1./(1+j.*Q.*(n1-1./n1)).*1./(1+j.*Q.*(n2-1./n2));  %l滤波器传递函数
    c2_abs=abs(c2);     %得到滤波器的幅频
    c2_ph=angle(c2)*180/pi;  %和相频响应
    
    m=max(c2_abs);
   subplot(2,1,1) 
   if dw==25
      a=plot(w/1000,c2_abs/m,'r');  
      set(a,'linewidth',3,'color','k');
   else
       plot(w/1000,c2_abs/m,'k--');
       %set(aa,'linewidth',1,'color','k--');
   end 
   
     n1=w./w0;
    c1=1./(1+j.*Q.*(n1-1./n1));
    c1_abs=abs(c1);c1_ph=angle(c1);
    a=plot(w/1000,c1_abs,'k');
    set(a,'linewidth',4,'color','r')
    hold on;
     
   hold on;grid minor;
   title('Q=20','FontSize',22);
   xlabel('ω/ω0','FontSize',25);
   ylabel('U/Umax','FontSize',25); 
   xlim([0.8,1.2]);
  % plot([1 1],ylim, 'r');  
   
   subplot(2,1,2)
    if dw==25 
       z=plot(w/1000,c2_ph,'r'); 
       set(z,'linewidth',3,'color','k')
    else
      plot(w/1000,c2_ph,'k--');
       %set(zz,'linewidth',1,'color','k--')
    end
    hold on;grid minor;
    %title('Q=20','FontSize',22);
    xlabel('ω/ω0','FontSize',25);
   % ylabel('Phase','FontSize',25); 
     ylabel('相位/^。','FontSize',25); 
    xlim([0.8,1.2]);
   
end