FIR EQIRIPPLE (OPTIMAL METHOD)

%LPF

clc

clear

close all

samp=2000;

n=0:1/samp:1;

x=cos(2*pi*100*n)+cos(2*pi*500*n)+cos(2*pi*700*n);

ap=0.5;%ap=-20*log10(1-dp)

as=80;%as=-20*log10(ds)

dp=1-10^(-ap/20);

ds=10^(-as/20);

[n,fo,mo,w] = firpmord( [300 400], [1 0], [dp ds], samp );

b = firpm(n,fo,mo,w);

[h,o]=freqz(b,1,256);

figure

plot(o/pi, 20*log10(abs(h)));

y=filter(b,1,x);

figure

subplot 211, plot(abs(fft(x)));

subplot 212, plot(abs(fft(y)));

%HPF

clc

clear

close all

samp=2000;

n=0:1/samp:1;

x=cos(2*pi*100*n)+cos(2*pi*500*n)+cos(2*pi*700*n);

ap=0.5;%ap=-20*log10(1-dp)

as=80;%as=-20*log10(ds)

dp=1-10^(-ap/20);

ds=10^(-as/20);

[n,fo,mo,w] = firpmord( [300 400], [0 1], [ds dp], samp );

b = firpm(n,fo,mo,w);

[h,o]=freqz(b,1,256);

figure

plot(o/pi, 20*log10(abs(h)));

y=filter(b,1,x);

figure

subplot 211, plot(abs(fft(x)));

subplot 212, plot(abs(fft(y)));

%BPF

clc

clear

close all

samp=2000;

n=0:1/samp:1;

x=cos(2*pi*100*n)+cos(2*pi*500*n)+cos(2*pi*700*n);

ap=0.5;%ap=-20*log10(1-dp)

as=80;%as=-20*log10(ds)

dp=1-10^(-ap/20);

ds=10^(-as/20);

[n,fo,mo,w] = firpmord( [300 400 550 650], [0 1 0], [ds dp ds], samp );

b = firpm(n,fo,mo,w);

[h,o]=freqz(b,1,256);

figure

plot(o/pi, 20*log10(abs(h)));

y=filter(b,1,x);

figure

subplot 211, plot(abs(fft(x)));

subplot 212, plot(abs(fft(y)));

%BSF

clc

clear

close all

samp=2000;

n=0:1/samp:1;

x=cos(2*pi*100*n)+cos(2*pi*500*n)+cos(2*pi*700*n);

ap=0.5;%ap=-20*log10(1-dp)

as=80;%as=-20*log10(ds)

dp=1-10^(-ap/20);

ds=10^(-as/20);

[n,fo,mo,w] = firpmord( [300 400 550 650], [1 0 1], [dp ds dp], samp );

b = firpm(n,fo,mo,w);

[h,o]=freqz(b,1,256);

figure

plot(o/pi, 20*log10(abs(h)));

y=filter(b,1,x);

figure

subplot 211, plot(abs(fft(x)));

subplot 212, plot(abs(fft(y)));