% ##################################################################################
% ##  Loesung:  Fensterfunktionen                                                 ##
% ##  --------------------------------------------------------------------------  ##
% ##  Benoetigte(s) m-File(s):  ldtft.m                                           ##
% ##################################################################################


% #####  Teilaufgabe a:  Fenstertyp berechnen  #####
window_length=[21 42];

for n=window_length                      %%%Rechteckfenster%%%
   n_find = find(n==window_length); 
   tltstr = 'Rechteck-Fenster';
   rw = boxcar(n);
   [Rw W] = ldtft(rw,512);
   
   i=find(abs(Rw)==0);                   % Vermeidung von Werten==0
   Rw(i)=1e-100*ones(size(i)); 
   if n_find==1
     figure;plot(W/pi,20*log10(abs(Rw/max(Rw))));
     axis([-1 1 -80 0]);grid;hold on;               
   end; 
   plot(W/pi, 20*log10(abs(Rw/max(Rw))),'--'); xlabel('Omega/pi');
   ylabel('|F(exp(j*Omega))/F(exp(j*0))| in dB');title([tltstr,' m: - 21 -- 42']); 
end;
hold off;
figure; stem(0:n-1,rw);grid; xlabel('k'); ylabel('f(k)'); title(tltstr);

for n=window_length                      %%%von Hann%%%
   n_find = find(n==window_length); 
   tltstr = 'von Hann-Fenster';
   rh = hanning(n);
   [Rh W] = ldtft(rh,512);

   i=find(abs(Rh)==0);                   % Vermeidung von Werten==0
   Rh(i)=1e-100*ones(size(i)); 
   if n_find==1
     figure;plot(W/pi,20*log10(abs(Rh/max(Rh)))); axis([-1 1 -80 0]);grid;hold on;
   end;
   plot(W/pi,20*log10(abs(Rh/max(Rh))),'--'); xlabel('Omega/pi');
   ylabel('|F(exp(j*Omega))/F(exp(j*0))| in dB');title([tltstr,' m: - 21 -- 42']);
end;   
hold off;
figure; stem(0:n-1,rh);grid; xlabel('k'); ylabel('f(k)'); title(tltstr);

for n=window_length                      %%%Hamming%%%
   n_find  = find(n==window_length); 
   tltstr  = 'Hamming-Fenster';
   rhm = hamming(n);
   [Rhm W] = ldtft(rhm,512);

   i=find(abs(Rhm)==0);                  % Vermeidung von Werten==0
   Rhm(i)=1e-100*ones(size(i)); 
   if n_find==1
     figure;plot(W/pi,20*log10(abs(Rhm/max(Rhm))));axis([-1 1 -80 0]);grid;hold on;
   end;
   plot(W/pi,20*log10(abs(Rhm/max(Rhm))),'--'); xlabel('Omega/pi');
   ylabel('|F(exp(j*Omega))/F(exp(j*0))| in dB');title([tltstr,' m: - 21 -- 42']);
end;  
hold off;
figure; stem(0:n-1,rhm);grid; xlabel('k'); ylabel('f(k)'); title(tltstr);
 
for n=window_length                      %%%Blackman%%%
   n_find  = find(n==window_length);  
   tltstr  = 'Blackman-Fenster';
   rhb = blackman(n);
   [Rhb W] = ldtft(rhb,512);

   i=find(abs(Rhb)==0);                  % Vermeidung von Werten==0
   Rhb(i)=1e-100*ones(size(i)); 
   if n_find==1
     figure;plot(W/pi,20*log10(abs(Rhb/max(Rhb))));axis([-1 1 -80 0]);grid;hold on;
   end;
   plot(W/pi,20*log10(abs(Rhb/max(Rhb))),'--'); xlabel('Omega/pi');
   ylabel('|F(exp(j*Omega))/F(exp(j*0))| in dB');title([tltstr,' m: - 21 -- 42']);
end;   
hold off;
figure; stem(0:n-1,rhb);grid; xlabel('k'); ylabel('f(k)'); title(tltstr);

for n=window_length                      %%%Bartlett%%%
   n_find  = find(n==window_length); 
   tltstr  = 'Bartlett-Fenster';
   rhbt = bartlett(n);
   [Rhbt W] = ldtft(rhbt,512);

   i=find(abs(Rhbt)==0);                 % Vermeidung von Werten==0
   Rhbt(i)=1e-100*ones(size(i)); 
   if n_find==1
     figure;plot(W/pi,20*log10(abs(Rhbt/max(Rhbt))));axis([-1 1 -80 0]);grid;
     hold on;          
   end;
   plot(W/pi,20*log10(abs(Rhbt/max(Rhbt))),'--'); xlabel('Omega/pi');    
   ylabel('|F(exp(j*Omega))/F(exp(j*0))| in dB');title([tltstr,' m: - 21 -- 42']);
end;  
hold off;
figure; stem(0:n-1,rhbt);grid; xlabel('k'); ylabel('f(k)'); title(tltstr);

% #####  Teilaufgabe b:  Kaiser-Fenster berechnen  #####
w0 = kaiser(21,0); [W0 W] = ldtft(w0,512);
w3 = kaiser(21,3); W3 = ldtft(w3,512);
w6 = kaiser(21,6); W6 = ldtft(w6,512);
k=0:20;

figure; plot(W/pi,20*log10(abs(W0/max(W0)))); xlabel('Omega/pi');axis([-1 1 -80 0]);
ylabel('|F(exp(j*Omega))/F(exp(j*0))| in dB'); hold on;
plot(W/pi,20*log10(abs(W3/max(W3))),'--');plot(W/pi,20*log10(abs(W6/max(W6))),'-.'); 
hold off; title('Kaiser-Fenster: beta: - 0,  -- 3,  -. 6'); grid; 
figure; plot(k,w0); xlabel('k');ylabel('f(k)');hold on; plot(k,w3,'--');
plot(k,w6,'-.'); axis([0 20 0 1.2]); hold off;
title('Kaiser-Fenster: beta: - 0,  -- 3,  -. 6      '); grid
% #####  EOF  #####