fp=2000;fs=10000;
fm=44100;fny=fm/2;

Ap=0.5;As=50;
run=1;

while run==1,
	N=input('Orden del Filtro N = ');
	B=fir2(N,[0 2000 6000 10000 fny]/fny,[1 1 0.5 0 0],hamming(N+1));
	[Hsp]=freqz(B,1,[fp fs],fm);
	ap=-20*log10(abs(Hsp(1)));as=-20*log10(abs(Hsp(2)));
	fprintf(1,'Ap=%f\tap=%f\n',Ap,ap);
	fprintf(1,'As=%f\tas=%f\n',As,as);
	otra=input('Otro filtro? S/N : ','s');
	if otra=='s' | otra=='S',
		run=1;
	else
		run=0;
	end
end
[H,F]=freqz(B,1,500,fm);
plot(F,20*log10(abs(H)));hold on;
plot([fp,fs],-[Ap As],'*r');hold off;zoom;grid;