calculating offset

[ASCologne]

Hallo,

how can I calculate the offset of two functions?

(Details: I have two 1D-arrays Y[1,...,N] and Z[1,...,N] with the N values of the two functions. I want to substract them from each other in a way that a part of the function is eliminated. My idea is the following:

sub[1,...,N]=0
for k=1 to N
for i=k to k+m (only the part [1,...,m] of Y is interesting to me and the offset i of Z)
if i<=N then sub[i]=Y[k]-Z[i] else sub[i]=0
next i
next k

I save each substration-array and select the one with the lowest sum. That index j should be the required offset.)

Note that my idea isn't programmed in LabVIEW yet, perhaps one of you has a better idea.

Arno

PS: If you attach a VI: I use LabVIEW 6.1, so please it in a way I can read it.

[vicky]

Hi,
iam sorry i coud not understand what you wanted ,are you looking for a VI which takes in 2 1D arrays and subtracts one another with a given offset.
plz explain it.

[ASCologne]

Hallo,

sorry for writing to complicated. Details:

I have two 1D-arrays. I want to substract one from the other. That's easy, if they don't have an offset. How can I calculate an existing one? As soon I have it, my problem is solved:

use the offset (x[i] -> x[i+offset]) and substract (y[i]-x[i+offset])

Example: First array: 1000 values of the sin x-function. Second array: 1000 values of the sin(x+1)-function. How can I calculate the "1"? Note: My function is NOT sin, and I do not know an analytic formula for it.

Perhaps now I am clearer.

Arno

[DOC-doc]

You have to compute the cross-correlation of the two vectors and the maximum will be you offset

[DOC-doc]

You have to compute the cross-correlation of the two vectors and the maximum will be you offset