Get spectral picture from a wavelet transform

Question

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

y=generate1(100,1000,1);

and got the following picture:

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)

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

Answer 1

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):

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.