I am trying to use LV's
built in FRF to perform transfer function averaging. However it does not
appear to average multiple sets of data correctly.
In LV 7.0 I
wrote a transfer function sub VI, which calculates the TF for only 1 set of
data at a time and does not average. I am trying to implement the FRF
function to do the required TF averaging.
I can read in the first set of data to the TF sub VI that I wrote, as well as
the FRF. Both output the same TF magnitude value, 48.236 (which is expected
since its only 1 set of data). When I read in the next set of data, the
TF magnitude for that set is 47.2095. Thus, I am expecting a average TF
magnitude of (48.236+47.2095)/2=47.2228. However, the FRF tells me the average
TF magnitude is 26.7809.
My averaging parameters cluster is as follows:
Vector Averaging
Linear
10
One Shot
I have one theory, but I cannot test it. My code was originally written
in LV 7.0. I
recently upgrade to LV
7.1. However, so that I was able run the VIs I wrote in LV
7.0, I needed to copy parts of my old LV 7.0
fdirectory to my LV
7.1 directory; and for some reason I can not the run the FRF which comes with
LV 7.1 (I get "unable to execute"
errors), so therefore I am using the FRF function which I had bundled into
my library of VIs which I wrote in LV
7.0. Could using the LV 7.0 FRF in LV
7.1 cause this averaging error?
