Spectrogram - How to divide signal ?

Hello

I have a signal 120 seconds long with sampling frequency 1KHz. How do I compute the spectrogram with 120 time segments ? Each segment 1000 samples. The code below gives me t = 136 not 120

segments = 120;     
windowsize = 1000;
nfft = 1000;

[S,F,T,P] = spectrogram(data,windowsize,segments,nfft,Fs);

Answer 1

[Rick Rosson]

The third input argument of spectrogram expects the number of samples to overlap each window, not the number of segments. Please try:

   winSize = 1000;
   overlap = 0;
   fftSize = winSize;

   [S,F,T,P] = spectrogram(data,winSize,overlap,fftSize,Fs);

It is common practice, however, to set the overlap to half of the window size:

   overlap = floor(winSize/2);

but it is not required if you don't want it.

HTH.

[Rab Nawaz]

@Rick Rosson! Please let me know how can I get wavelet coefficients in the same manner i.e. by dividing the signal in 'N' number of segments and with or without overlap. Alternatively, is there any way to get wavelet coefficients from this spectrogram function.