nested for loop

This code gives me 6 subplots like I need, howerver, what I'd like to do is for each subplot i'd like the X to switch trhough 5 other letters.

for i=1:6;

Zu = 1;

subplot(3,2,i)

Str = sprintf('X%d',Zu );

Hs=spectrum.periodogram;

psdest = psd(Hs,eval(Str),'Fs',Fs);

semilogx(psdest.Frequencies,10*log10(psdest.Data));

grid on;

xlabel('Frequency (Hz)')

ylabel('dB/Hz')

title(Str);

end

Answer 1

[Fangjun Jiang]

Letter={'X','Y','Z','K','V'};
for i=1:6
  for k=1:length(Letter)
      str=sprintf('%s%d',Letter{k},i);
  end
end