% Spectrogram of vowels A,E,I,O,U
[Y, fs, Nbits]=wavread('aeiou.wav');  % 1.9093 sec
% You can produce the above wav file at http://atc.ccl.itri.org.tw/ 
% Welcome to the Text-to-Speech Engine demo Advanced Technology Center
% ICL/ITRI 歡迎使用工研院(ITRI: Industrial Technology Research Institute of
% Taiwan, R.O.C)資通所前瞻技術中心研發的 中文文字轉語音合成系統
N = length(Y); T=1/fs;  % fs=16000; N=30548; Nbits=16
figure; plot([0:N-1]*T,Y)
soundsc (Y,fs)
L = 256;  
% Compute spectrogram by Matlab built-in function specgram.m（uses a Hanning window）
figure; specgram(Y, L, fs, 256, 128); 

% Compute spectrogram by the function f_specgram.m （a little changed by Tang）created by Schilling & Harris
L = 256; Hamming = 3; levels = 12;
[G,f,t] = f_specgram (Y,L,fs,Hamming);
figure;
contour(t,f(1:L/2),G(1:L/2,:),levels)   % Original: contour(t,f(1:L/2),G(:,1:L/2),levels)
f_labels ('Spectrogram of vowels: Hamming window','{\itt} (sec)','{\itf} (Hz)','\it{G(t,f)}');