# Signal Correlation (2D Auto-Correlation) (G Dataflow)

Version:

Computes the two-dimensional auto correlation of a sequence.

## X

The input sequence.

This input can be a 2D array of double-precision, floating-point numbers or a 2D array of complex double-precision, floating-point numbers.

## error in

Error conditions that occur before this node runs. The node responds to this input according to standard error behavior.

Default: No error

## RXX

The auto correlation of the input sequence.

## error out

Error information. The node produces this output according to standard error behavior.

## Algorithm for Calculating the 2D Auto-Correlation

This node computes two-dimensional auto-correlation using the following equation:

$y\left(i,j\right)=\underset{m=0}{\overset{M-1}{\sum }}\underset{n=0}{\overset{N-1}{\sum }}{x}^{*}\left(m,n\right)\cdot x\left(m+i,n+j\right)$

for i = -(M-1), ..., -1, 0, 1, ... , (M-1) and j = -(N-1), ..., -1, 0, 1, ... , (N-1)

where M is the number of rows of matrix X and N is the number of columns of matrix X. The indexed elements of X that lie outside its range are equal to zero, as shown in the following relationship:

$x\left(m,n\right)=0,\text{\hspace{0.17em}}m<0\text{\hspace{0.17em}}\mathrm{or}\text{\hspace{0.17em}}m\ge M\text{\hspace{0.17em}}\mathrm{or}\text{\hspace{0.17em}}n<0\text{\hspace{0.17em}}\mathrm{or}\text{\hspace{0.17em}}n\ge N$

Where This Node Can Run:

Desktop OS: Windows

FPGA: Not supported