Phase shift correction between 2 signals using cross-correlation
69 vues (au cours des 30 derniers jours)
Afficher commentaires plus anciens
Hello
I'm in need of some help if you please.
I have 2 sinsoidal signals with a phase shift of 2Pi/3 between them. Basically, I need to eliminate the phase shift and obtain 2 signals with the same phase. I'm looking forward to use the cross-correlation, that represents the differnce between both signals (the phase shift, in our case), to do so.
My problem is to know how to use the cross-correlation to "correct" the shifted signal by eliminating the phase shift indiquated by the cross-correlation. Which operation to use to do so?
Here is a portion of the code for further understanding :
t = 1 : 1000;
phaseshift= 2*pi/3;
s1 = sin (2*pi*t/500);
s2 = sin (2*pi*t/500+ phaseshift);
figure(1); clf;
plot (t,s1, t,s2);
Axis_x = [-length(s1)+1 : 1 : length(s1)-1];
cross_corr = xcorr(s1,s2,'coeff');
figure(2); clf;
plot( Axe_x, coss_corr,'r');
Thanks in advance
0 commentaires
Réponse acceptée
dpb
le 18 Fév 2015
Modifié(e) : dpb
le 18 Fév 2015
[c,lags]=xcorr(s1,s2); % compute cross correlation; keep lags vector
[~,iLag]=max(c(find(lags==0):end)); % find the max in one-sided
s3=circshift(s2,[0 iLag]); % correct for the shift
For your case I get
>> [~,iLag]=max(c(1000:end))
iLag =
162
>> 2*pi*iLag/500
ans =
2.0358
>> phaseshift
phaseshift =
2.0944
This isn't perfect; illustrates even with pure sine
8 commentaires
ZIYI LIU
le 17 Mai 2022
Hi dpb,
What if I don't know the functions of these two lines, but only two set of data like these two lines. Then I can have the lags, how do I know the phase shift? Thanks!
Plus de réponses (1)
Voir également
Catégories
En savoir plus sur Matched Filter and Ambiguity Function dans Help Center et File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!