[Tftb-help] achieving the power spectrum by integration of the WVD

[Hallgrímur Th . Björnsson]

Hello there.

 

I‘m trying to achieve the power spectrum by integrating the TFR obtained from using the WVD of  the toolbox. In my understanding, I should approximately arrive at a similar conclusion as using the fft.

The problem is that, when plotting the resulting value from the integration, there seems to have been a frequency shift by 2 * f. So, if I have a sinusoid of frequency 50Hz, the spectrum by integrating the WVD shows a 100Hz component. I have tried to use the CWD also, and the same problem is also in that case.

 

Here is my Matlab code:

 

close all

clear

t=linspace(0,1,1000);

f1=50;

figure

x=sin(2*pi*f1*t);

subplot(2,1,1)

plot(abs(fft(x)))

 

[TFR,T,F]=tfrwv(x);

 

intg=integ(TFR);

subplot(2,1,2)

 

plot(intg)

 

Can anyone help?

 

Thanks