how to find sum of series for a complex function?

I had IRx1,QRx1,IRx2,QRx2 vectors

IRx1=[-3.4,2.47,..........27.3]

QRx1=[2.3.............54.5]

the length of IRx1,QRx1,IRx2 and QRx2 are 128.length for all vectors is same that is 128.

     x(n)=IRx1+i*QRx1 (complex signal)

     y(n)=IRx2+i*QRx2 (complex signal)

i want to find auto correlation for X and cross correlation for X and y. by using below formulaes

ACF(k)=∑(n=0 to 128)〖x(n).*x(n-k) 〗

CCF(k)=∑(n=0 to 128〖x(n).*y(n)〗

Here i attached images of equations also. I tried so many times i am getting errors.

Help me to find ACF and CCF of given complex signals?

Answer 1

[Thibaut Jacqmin]

What you want to compute looks like a convolution. Would this do the work ? Note that CCF does not depend on k in your expression. Are you sure it is not the sum over n of x(n)*y(n-k) ? You can get more info abour the conv function here ("More about" section):

https://fr.mathworks.com/help/matlab/ref/conv.html

x = complex(IRx1, QRx1);
y = complex(IRx2, QRx2);

ACF= conv(x, x);
CCF = conv(x, y);