Normalized Cross correlation, Normalized autocorrelation

Hey everybody, I have these Golay Sequences: GolaySeq=[+1 [phone] +1 -1 +1 +1 -1 -1 +1]; Vec=[ repmat(GolaySeq,1,16) -GolaySec]; SNR=20; Vec2 = awgn(Vec,SNR); Now I want to have Normalized Cross correlation and Normalized autocorrelation of it like attached file. Could anybody help me out of this? Tnx a lot.

Answer 1

[zainab alsaffar]

corr2(A,B) u can use it for cross and auto normalized correlation

[mahdi safarzadeh]

Thanks a lot dear zainab, I know how to calculate the autocorrelation or cross-correlation. I don't know how to do a normalization with the formula I just attached. of course in the formula instead of 128 I should put 16(the size of my vector)

[Greg Heath]

What 128 ?

Isn't corr2 already scaled?

corr2(zscore(A,1),zscore(B,1))= corr2(A,B)

Answer 2

[Wayne King]

If you have the Signal Processing Toolbox, use xcorr(). I'll assume your -GolaySec above is a typo and should read -Golayseq

GolaySeq=[+1 [phone] +1 -1 +1 +1 -1 -1 +1]; 
Vec=[ repmat(GolaySeq,1,16) -GolaySeq]; 
SNR=20; 
Vec2 = awgn(Vec,SNR);
% normalized autocorrelation
[ac,lags] = xcorr(Vec2,'coef');
% cross correlation
[xc,lags] = xcorr(Vec,Vec2,'coef');

Choose the appropriate number of lags for your purposes.