I need to align 3 signals by cross correlation

I have 3 signals. I am using the code in https://uk.mathworks.com/help/signal/ug/align-signals-using-cross-correlation.html. My problem is the following. In my case I cannot represent the graph with the three signals, so I need to generate a code that can align them without knowing a priory which one lags or leads.

I have been trying different options and I cannot seem able to find the way. The following code seems to work sometimes :S

%compare 2-1// 3-1

[C21,lag21] = xcorr(s2,s1);

[M21,I21] = max(C21);

t21 = lag21(I21);

[C31,lag31] = xcorr(s3,s1);

[M31,I31] = max(C31);

t31 = lag31(I31);

% compare 3-2 1-2

[C32,lag32] = xcorr(s3,s2);

[M32,I32] = max(C32);

t32 = lag32(I32);

[C12,lag12] = xcorr(s1,s2);

[M12,I12] = max(C12);

t12 = lag12(I12);

%compare 1-3//2-3

[C13,lag13] = xcorr(s1,s3);

[M13,I13] = max(C13);

t13 = lag13(I13);

[C23,lag23] = xcorr(s2,s3);

[M23,I23] = max(C23);

t23 = lag23(I23);

if t23<0

s3 = s3(-t23+1:end);

if t21>0

s2 = s2(t21+1:end);

else

s1 = s1(-t21+1:end);

end

else

s2 = s2(t23:end);

if t21<0

s1 = s1(-t31+1:end);

else

s2 = s2(t21+1:end);

end

end

Answer 1

[Star Strider]

The alignsignals function (or simlar functions such as findsignal) could do what you want. With 3 signals, it would be necessary to run it 1 time for each pair of signals (e.g. 1,1; 1,2; 1,3; 2,3) and then check the results, and repeat until you are satisfied with the result.

I am not certain if it would be possible to align all 3 signals at the same time.

[Jorge Garcia Garcia]

Thanks.. will try. This is driving me mental

[Star Strider]

My pleasure!