Phase shift correction between 2 signals using cross-correlation
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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
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dpb
2015-2-18
编辑:dpb
2015-2-18
[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
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ZIYI LIU
2022-5-17
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!
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