//GRZEBIENIOWY

 fp=250;
 fs=50;
 A=1;
 t=(0:500)/fp;

Tp=1/fp;
y=A*sin(2*pi*fs*t);
figure;
plot(t,y);
 g=fft(y,fp);
g=abs(g).^2./fp;
figure;
semilogy((0:fp/2-1),g(1:fp/2));

q=0.5;
L = [1 0 0 0 0 -1];
M = [1 0 0 0 0 -(1-q)];
y = filter(L,M,y);
figure;
plot(y);

g=fft(y,fp);
g=abs(g).^2./fp;
figure;
semilogy((0:fp/2-1),g(1:fp/2));
fvtool(L,M);


// NOTCH

 fp=250;
 fs=50;
 A=1;
 t=(0:500)/fp;

Tp=1/fp;
y=A*sin(2*pi*fs*t);
figure;
plot(t,y);
 g=fft(y,fp);
g=abs(g).^2./fp;
figure;
semilogy((0:fp/2-1),g(1:fp/2));
a=-2*cos(2*pi*fs*Tp);
r=1.1;
b=1.1;
L = [1 a 1];
M = [r^2 a*b 1];
y = filter(L,M,y);
figure;
plot(y);

g=fft(y,fp);
g=abs(g).^2./fp;
figure;
semilogy((0:fp/2-1),g(1:fp/2));
fvtool(L,M);


// ZERUJACY

fp=250;
 fs=50;
 A=1;
 t=(0:500)/fp;
Tp=1/fp;
y=A*sin(2*pi*fs*t);
figure;
plot(t,y);
 g=fft(y,fp);
g=abs(g).^2./fp;
figure;
semilogy((0:fp/2-1),g(1:fp/2));


L = [1 -2*cos(2*pi*fs*Tp) 1];
M = [1];
y = filter(L,M,y);
figure;
plot(y);

g=fft(y,fp);
g=abs(g).^2./fp;
figure;
semilogy((0:fp/2-1),g(1:fp/2));
fvtool(L,M);