clear all; close all; 
Fs=8000; N=5; F1=250; F2=750; 
sigLen=Fs*N; 
subplot(3,2,1);
spY=30000;
mysig=[];
myperiod=[ones(1,Fs/F1/2) -ones(1,Fs/F1/2)];
for idx=1:(F1*N); mysig=[mysig myperiod]; end
stem(mysig);
ylim([-2,2]); xlim([0,200]);
title(sprintf('%dHz pravouhly signal',F1));
subplot(3,2,2); 
mySp=fft(mysig);
stem (abs(mySp));
xlim([0,sigLen]); ylim([-spY,spY]);
subplot(3,2,3);
mysig2=[];
myperiod2=[ones(1,round(Fs/F2/2)) -ones(1,round(Fs/F2/2))]
for idx=1:(F2*N); mysig2=[mysig2 myperiod2]; end
stem(mysig2);
ylim([-2,2]); xlim([0,200]);
title(sprintf('%dHz pravouhly signal',F2));
subplot(3,2,4);
mySp2=fft(mysig2); 
stem (abs(mySp2)); 
xlim([0,sigLen]); ylim([-spY,spY]);
subplot(3,2,6);
sigLen=Fs*N; z1=F1*N; mySp(z1+1)=0; 
mySp(sigLen-z1+1)=0; 
stem (abs(mySp)); 
xlim([0,sigLen]); ylim([-spY,spY]);
subplot(3,2,5)
mysigA=real(ifft(mySp));
stem(mysigA);
ylim([-2,2]);
xlim([0,200]);
title(sprintf('%dHz pravouhly signal bez základnej frekvencie',F1));
print(gcf,'missingBase.png','-dpng');
sound(mysig, Fs);  display("hram 250Hz signal, stlac klavesu"); pause;
sound(mysig2, Fs); display("hram 750Hz signal, stlac klavesu"); pause;
sound(mysigA, Fs); display("hram filt. 250Hz signal, stlac klavesu"); pause;