MATLAB设计模拟带通滤波器

设计一个模拟带通滤波器，其Ap=1dB,As=34dB,通带从200HZ到300HZ，阻带在100HZ-400HZ，设计满足上述条件的巴特沃斯滤波器 切比雪夫1 切比雪夫2 椭圆滤波器 。

这是我考试时候的程序，参数自己改一下就可以了

cheb1

% wp1=0.45*pi;wp2=0.65*pi;ws1=0.3*pi;ws2=0.75*pi;Rp=1;Rs=40

% =============双线型变换法=========================================

wp1=0.45*pi; wp2=0.65*pi;

ws1=0.3*pi; ws2=0.75*pi;

Rp=1; Rs=40;

Wp1=tan(wp1/2); Wp2=tan(wp2/2);

Ws1=tan(ws1/2); Ws2=tan(ws2/2);

BW=Wp2-Wp1; W0=Wp1*Wp2; W00=sqrt(W0);

WP=1; WS=WP*(W0^2-Ws1^2)/(Ws1*BW);

[N,Wn]=cheb1ord(WP,WS,Rp,Rs,'s');

[B,A]=cheby1(N,Rp,Wn,'s');

[BT,AT]=lp2bp(B,A,W00,BW);

[num,den]=bilinear(BT,AT,0.5);

[h,omega]=freqz(num,den,64);

subplot(2,2,1);stem(omega/pi,abs(h));

xlabel('\omega/\pi');ylabel('|H(z)|');

subplot(2,2,2);stem(omega/pi,20*log10(abs(h)));

xlabel('\omega/\pi');ylabel('增益.dB');

% =============直接法=================================

wp1=0.45*pi; wp2=0.65*pi;

ws1=0.3*pi; ws2=0.75*pi;

Rp=1; Rs=40;

Wp=[wp1/pi,wp2/pi]; Ws=[ws1/pi,ws2/pi];

[N,Wn]=cheb1ord(Wp,Ws,Rp,Rs);

[B,A]=cheby1(N,Rp,Wn);

[h,omega]=freqz(B,A,64);

subplot(2,2,3);stem(omega/pi,abs(h));

xlabel('\omega/\pi');ylabel('|H(z)|');

subplot(2,2,4);stem(omega/pi,20*log10(abs(h)));

xlabel('\omega/\pi');ylabel('增益.dB');

%cheby2%

% wp1=0.45*pi;wp2=0.65*pi;ws1=0.3*pi;ws2=0.75*pi;Rp=1;Rs=40

% =============双线型变换法=========================================

wp1=0.45*pi; wp2=0.65*pi;

ws1=0.3*pi; ws2=0.75*pi;

Rp=1; Rs=40;

Wp1=tan(wp1/2); Wp2=tan(wp2/2);

Ws1=tan(ws1/2); Ws2=tan(ws2/2);

BW=Wp2-Wp1; W0=Wp1*Wp2; W00=sqrt(W0);

WP=1; WS=WP*(W0^2-Ws1^2)/(Ws1*BW);

[N,Wn]=cheb2ord(WP,WS,Rp,Rs,'s');

[B,A]=cheby2(N,Rs,Wn,'s');

[BT,AT]=lp2bp(B,A,W00,BW);

[num,den]=bilinear(BT,AT,0.5);

[h,omega]=freqz(num,den,64);

subplot(2,2,1);stem(omega/pi,abs(h));

xlabel('\omega/\pi');ylabel('|H(z)|');

subplot(2,2,2);stem(omega/pi,20*log10(abs(h)));

axis([0 1 -100 0]);xlabel('\omega/\pi');ylabel('增益.dB');

% =============直接法=================================

wp1=0.45*pi; wp2=0.65*pi;

ws1=0.3*pi; ws2=0.75*pi;

Rp=1; Rs=40;

Wp=[wp1/pi,wp2/pi]; Ws=[ws1/pi,ws2/pi];

[N,Wn]=cheb2ord(Wp,Ws,Rp,Rs);

[B,A]=cheby2(N,Rs,Wn);

[h,omega]=freqz(B,A,64);

subplot(2,2,3);stem(omega/pi,abs(h));

xlabel('\omega/\pi');ylabel('|H(z)|');

subplot(2,2,4);stem(omega/pi,20*log10(abs(h)));

axis([0 1 -100 0]);xlabel('\omega/\pi');ylabel('增益.dB');

%椭圆%

% wp1=0.45*pi;wp2=0.65*pi;ws1=0.3*pi;ws2=0.75*pi;Rp=1;Rs=40

% =============双线型变换法=========================================

wp1=0.45*pi; wp2=0.65*pi;

ws1=0.3*pi; ws2=0.75*pi;

Rp=1; Rs=40;

Wp1=tan(wp1/2); Wp2=tan(wp2/2);

Ws1=tan(ws1/2); Ws2=tan(ws2/2);

BW=Wp2-Wp1; W0=Wp1*Wp2; W00=sqrt(W0);

WP=1; WS=WP*(W0^2-Ws1^2)/(Ws1*BW);

[N,Wn]=ellipord(WP,WS,Rp,Rs,'s');

[B,A]=ellip(N,Rp,Rs,Wn,'s');

[BT,AT]=lp2bp(B,A,W00,BW);

[num,den]=bilinear(BT,AT,0.5);

[h,omega]=freqz(num,den,64);

subplot(2,2,1);stem(omega/pi,abs(h));grid;

xlabel('\omega/\pi');ylabel('|H(z)|');

subplot(2,2,2);stem(omega/pi,20*log10(abs(h)));grid;

xlabel('\omega/\pi');ylabel('增益.dB');

% =============直接法=================================

wp1=0.45*pi; wp2=0.65*pi;

ws1=0.3*pi; ws2=0.75*pi;

Rp=1; Rs=40;

Wp=[wp1/pi,wp2/pi]; Ws=[ws1/pi,ws2/pi];

[N,Wn]=ellipord(Wp,Ws,Rp,Rs);

[B,A]=ellip(N,Rp,Rs,Wn);

[h,omega]=freqz(B,A,64);

subplot(2,2,3);stem(omega/pi,abs(h));grid;

xlabel('\omega/\pi');ylabel('|H(z)|');

subplot(2,2,4);stem(omega/pi,20*log10(abs(h)));grid;

xlabel('\omega/\pi');ylabel('增益.dB');