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According to my previous question, I have changed the generate command to: 

y=generate1(100,1000,1);

and got the following picture:

enter image description here

Now I want to test a wavelet transform on the same signal, which of course exists in Matlab, but I have one thing which I should clarify: generally, as I know large scale values correspond to small frequencies and small scale values to large frequencies. So, how should I determine if the given frequencies are small or large? Also, which wavelet transform should i use?

For example:

m=cwt(y,1:100,'sym2');

and plot it

plot(m)

enter image description here

How should I read the second picture? What kind of information can I get?

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Try this one:

m=cwt(y,1:100,'sym2','plot');
colormap(pink)

Result (btw, I cannot reproduce your curve in time domain with the function generate1):

enter image description here

Low scale values compress the wavelet and correlate better with high frequencies. While high scale values stretch the wavelet and correlate better with the low frequency content of the signal.

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  • $\begingroup$ does this picture shows peaks at given frequency's in signal? $\endgroup$
    – dato datuashvili
    Jan 4 '14 at 16:26
  • $\begingroup$ They are CWT coefficients (mathworks.com/help/wavelet/gs/…), but I guess it is somehow equivalent to the power within the scaling window. $\endgroup$
    – lennon310
    Jan 4 '14 at 16:35

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