Hioki MEMORY HiCORDER 8855, Instruction Manual

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4.8 FFT Analysis Function
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(Overall value) = (Vrms)
Window compensation value:
γ
Square wave:
γ
= 1
8
Hanning: γ =
3
2 log(
α
/100)
Exponential:
γ
=
(
α
/100)
2
- 1
Overall value
The overall value is the total effective value obtained from the frequency
spectrum contained in the input signal. It is obtained by taking the square
root of the total of power spectra for all frequencies.
PSPo DC component
PSPi ith AC component
Compensation is applied to data for specified points captured before starting
FFT processing, to achieve the same overall value, also when a window
function other than rectangular window is used.
(
α
is a percentage with a range of 0 <=
α
< 100.)
If
α
is set to 0 with the exponential window function, processing will be
carried with
α
= 0.1.