L=401;
h=fir1(N-1,0.5);

f1=0.2;
f2=0.4;
f3=0.8;

tp=0.0;
tk=10.0;
deltat=0.01;
t=[tp:deltat:tk];

x1=sin(2*pi*f1*t);
x2=sin(2*pi*f2*t);
x3=sin(2*pi*f3*t);

xsuma=x1+x2+x3;

fp=(f3*2)/1;
T=1/fp;

w=bartlett(L)

figure(1)
y1=h*w;