how to make an exponential x-axis in a waveform-cluster?

[Benne]

I have some data sampled with a signal analyzer. I have the data in 2
arrays, X and Y axis.
The X-axis is frequency, which is exponential, 10 Hz to 30kHz, and the
Y-axis is the actual measured signal level.

Then in Labview I want to check this waveform against limits. So I
have set up with the methods "limit specifications" my limits, and
plan to use "limit testing" for testing my waveform is within certain
limits.

However, now to the problem.
"limit testing" in the frequency domain requires a signal input of the
kind which is a cluser of f0, df and then the actual data, spectrum.

f0 is 10Hz ofcourse
spectrum is my Y-array. No problem so far

BUT, df? what is df if the X-axis is exponential?
Does anyone has any advice for me how to solve this problem or some
clever work around?

[GerdW]

Hi Benne,

why do you ask the same question again (with missing picture attachments) but now using a different user name?

Please stop creating double posts!