i was trying this code but getting error for Y=fft(x.*h​amming(len​gth(x))); as .* operator matrix dimensions must agree.pls help me to resolve.

% estimation of fundamental frequency in frequency domain

[x,fs]=wavread('1.wav',[24120 25930]);

ms1=fs/1000; % maximum speech Fx at 1000Hz

ms20=fs/50; % minimum speech Fx at 50Hz

% plot waveform

t=(0:length(x)-1)/fs; % times of sampling instants

subplot(3,1,1);

plot(t,x);

legend('Waveform');

xlabel('Time (s)');

ylabel('Amplitude');

% do fourier transform of windowed signal

Y=fft(x.*hamming(length(x)));

% plot spectrum of bottom 5000Hz

hz5000=5000*length(Y)/fs;

f=(0:hz5000)*fs/length(Y);

subplot(3,1,2);

plot(f,20*log10(abs(Y(1:length(f)))+eps));

legend('Spectrum');

xlabel('Frequency (Hz)');

ylabel('Magnitude (dB)');

% cepstrum is DFT of log spectrum

C=fft(log(abs(Y)+eps));

% plot between 1ms (=1000Hz) and 20ms (=50Hz)

q=(ms1:ms20)/fs;

subplot(3,1,3);

plot(q,abs(C(ms1:ms20)));

legend('Cepstrum');

xlabel('Quefrency (s)');

ylabel('Amplitude');

Answer 1

[Honglei Chen]

My guess is your x is a row vector while hamming(length(x)) gives a column vector. You can add

x = x(:);

after second line to resolve this issue.

[Dhanashri]

thanks a lot for your reply...ur suggestion has helped me to solve above prob...