App-7
IM AQ6376-01EN
Appendix
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App
Index
RMS Method
Use the RMS method to obtain the spectrum width and its center wavelength.
Following table shows the details of parameters for the RMS method.
Parameter Abbreviation Default Value Setting Range Unit Description
THRESH
TH
20.00
0.01 to 50.00
dB
Threshold value
K
K
2.00
1.00 to 10.00
-
Multiplying factor
Algorithms for the analysis are described below.
Peak Level
Threshold
Value
• Take out the data points exceeding the
threshold value TH, within the displayed
waveform, and find the spectrum width by the following calculation.
• When the wavelength at beach point isλi and the level at the point is Pi, the mean
wavelength
λ
c can be found by the following expression.
λ
c =
∑
λ
i
Pi x
∑
Pi
• By using the mean wavelength
λ
c, find the spectrum width
Δλ
by the following
expression.
Δλ
=
∑
(
λ
i -
λ
c
)
Pi x
∑
Pi
2
K x
Appendix 2 Data Calculation Algorithms for Spectrum Widths