Phase spectrum without knowing frequency

Hi to Matlab Community!

I would appreciate if anyone knows if possible to phase a spectrum if you have only the x,y data. Namely if you look at the attached picture, I woyldl ike to ask you if there is any prossibilty to phase the below spectrum to look like the above???

Thnak you for your help!

Answer 1

[Star Strider]

The lower trace appears to be the negative derivative of the upper trace.

So integrating the negative of the lower trace and adding a constant-of-integration could approximate the upper trace. With only an image and no vectors to experiment with, this is as close as I can get.

[abaza]

Thank you so much for your reply!!!

Please find the .mat file for both spectra!

I cannot see how could I phase the not phased spectrum!

Thank you again!

[Star Strider]

My pleasure.

Try this:

D = load('phase.mat');
Good = D.Good;
notphased = D.notphased;
int_np = cumtrapz(notphased(:,1), notphased(:,2));  % Integrate
IntConst = mean(Good(:,2) - int_np);                % Calculate Constant Of Integration

figure
plot(Good(:,1), Good(:,2))
hold on
plot(notphased(:,1), notphased(:,2)./100)
plot(notphased(:,1), int_np)
plot(notphased(:,1), int_np+IntConst, '--r', 'LineWidth',1.5)
hold off
grid
legend('Original','Not Phased','Integrated Not Phased','Constant-Corrected Integrated Not Phased', 'Location','SE')

producing:

[abaza]

THANK YOU SO MUCH!!!!

[Star Strider]

As always, my pleasure!