Hello,

I am trying solve something I thought would be straigfoward, but is not so far ^^.

Let assume we have a perriodic signal as such:
x=0:400;
T=39.5;
PhiO=0.43;
y=5+cos((2*pi/T).*x+PhiO);

And the aim is to get the phase and period of this signal.
Here is for the code for the period retriaval:
%period
[pks,locs] = findpeaks(y,’MinPeakDistance’,20) ;
Px_av=mean(diff(locs));
Here is the code for the phase retrieval:

h=fft(y);
plot(abs(h)) % the eleventh element is the frequency of my signal so the eleventh element of the phase "angle(h)" should be the phase of my signal. But if I plot the original signal and the retrieved one, it doesn’t match well:
Phi=angle(h);
plot(x,max(y).*cos((2*pi/Px_av).*x+Phi(1,11)));hold on;plot(x,y)

Given that PhiO and Px_av are different, I tried to use interp Phi to match the right frequency, but it doesn’t work either.

Do you understand what I do wrong, please ?Hello,

I am trying solve something I thought would be straigfoward, but is not so far ^^.

Let assume we have a perriodic signal as such:
x=0:400;
T=39.5;
PhiO=0.43;
y=5+cos((2*pi/T).*x+PhiO);

And the aim is to get the phase and period of this signal.
Here is for the code for the period retriaval:
%period
[pks,locs] = findpeaks(y,’MinPeakDistance’,20) ;
Px_av=mean(diff(locs));
Here is the code for the phase retrieval:

h=fft(y);
plot(abs(h)) % the eleventh element is the frequency of my signal so the eleventh element of the phase "angle(h)" should be the phase of my signal. But if I plot the original signal and the retrieved one, it doesn’t match well:
Phi=angle(h);
plot(x,max(y).*cos((2*pi/Px_av).*x+Phi(1,11)));hold on;plot(x,y)

Given that PhiO and Px_av are different, I tried to use interp Phi to match the right frequency, but it doesn’t work either.

Do you understand what I do wrong, please ? Hello,

I am trying solve something I thought would be straigfoward, but is not so far ^^.

Let assume we have a perriodic signal as such:
x=0:400;
T=39.5;
PhiO=0.43;
y=5+cos((2*pi/T).*x+PhiO);

And the aim is to get the phase and period of this signal.
Here is for the code for the period retriaval:
%period
[pks,locs] = findpeaks(y,’MinPeakDistance’,20) ;
Px_av=mean(diff(locs));
Here is the code for the phase retrieval:

h=fft(y);
plot(abs(h)) % the eleventh element is the frequency of my signal so the eleventh element of the phase "angle(h)" should be the phase of my signal. But if I plot the original signal and the retrieved one, it doesn’t match well:
Phi=angle(h);
plot(x,max(y).*cos((2*pi/Px_av).*x+Phi(1,11)));hold on;plot(x,y)

Given that PhiO and Px_av are different, I tried to use interp Phi to match the right frequency, but it doesn’t work either.

Do you understand what I do wrong, please ? phase retrieval, matlab, fft MATLAB Answers — New Questions

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