RunXCorr Documentation
Makes a cross correlation of the two input traces. This is a full (non-gated) cross correlation. To effect a gate, restrict one of the input vectors to the length of the gate.
Usage
The program is used as follows:
runXCorr input1FileName input2FileName
Where the input1FileName and input2FileName are in our standard file format.
Output
The output of the program appears one place:
(1) A copy of the output data is placed in the file lastDataOutput.
Theory
The formula used for this cross correlation is:
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which of course is the non-gated version. (In this
case, means over all available samples.
A gated version would be over a subset of selected samples, and have the formula:
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where the length of the gate would be 2N+1.
We can further generalize the formula by noting that the lengths of H and G, and the lengths of the gates of H and G need not be the same. In those cases, we can extend the values of H and G accordingly by 0 padding. This is what is done implicitly in MtConv.
Both equations produce numbers in the interval [-1,1]. 1 is
achieved when .,
and -1 is achieved when
.
In the case of band limited data, and finite sample lengths Equation (1.2) is preferred. However, with judicious use of 0 padding, that will be the case.s
Wm P. Kamp