scale to frequency

[Junyinghouse]

Hi Sir,

Apologies, I sent the email below already, but just thought I'd repost here for others.

I have used cwt in wavelib to perform time frequency analysis. Parameters were set as exactly same as online demo,showing below. I exported results, abs(cwt.ouput), and plot in Matlab with jet colormap. However the spectrogram was much difference.

what's more. I thought converting scale to frequency obeys the formular, Fb = dt*Fc/scale, Fc is the center frequency of morlet mother mavelet, equals to 0.8125Hz. The result seems not in this case.

I have tried to set my scales by using setCWTScaleVector , and reconstructed the signal. In fact there exists big variance between reconstructed signal and raw signal.

I am really confused and not familar with cwt. Could you be able to provide me with some guidance on doing time-frequency analysis with wavelib? I'd very much appreciate the help.

Best regards
Junying

[journeytosilius]

Hi @Junyinghouse I was looking at the demo and documentation and I could not find the frequency output. Can you share code on how are you getting the frequency out of the CWT result ?

As I understand, is this how you get frequency ?

        double Fb;
        double Fc = 0.8125;
        vector<double> frequency;

        for (int v = 0; v < N; ++v)
        {
            Fb = dt * Fc / wt->scale[v];
            frequency.push_back(Fb);
        }