YOKOGAWA AQ6373, User Manual, Page: 307 / 358

App-2
IM AQ6373-01EN
In the case of two or more mode peaks
Δ L
(”MODE FIT” ON)
Δ L (”MODE FIT” OFF)
L
1
’ L
1
L
2
L
2
’
Threshold
Value
• If “MODE FIT” is ON, set the wavelengths of the mode peaks, which are outmost from
the threshold value (THRESH[dB]) among the mode peaks, to
λ
1
and
λ
2
. If “MODE
FIT” is OFF, set the wavelengths, which are located outside
λ
1
and
λ
2
, and which cross
the line below the mode peak with the largest mode peak level by the threshold value
(THRESH[dB]), to
λ
'
1
and
λ
'
2
.
• If “MODE FIT” is ON, use the following equations, which incorporate multiplication by
the multiplying factor K for
λ
1
and
λ
2
, to obtain new
λ
1
and
λ
2
.
When “MODE FIT” is ON
λ
'C = (
λ
2
+
λ
1
)/2
λ
1
= K × (
λ
1
-
λ
'C) +
λ
'C
λ
2
= K × (
λ
2
-
λ
'C) +
λ
'C
When “MODE FIT” is OFF
λ
'C = (
λ
'
2
+
λ
'
1
)/2
λ
'
1
= K × (
λ
'
1
-
λ
'C) +
λ
'C
λ
'
2
= K × (
λ
'
2
-
λ
'C) +
λ
'C
• Obtain spectrum widths from the following equations.
Δλ
=
λ
2
-
λ
1
(when “MODE FIT” is ON)
Δ
λ =
λ
'
2
-
λ
'
1
(when “MODE FIT” is OFF)
• Obtain center frequencies
λ
C from the following equations
λ
C = (
λ
2
+
λ
1
)/2 (when “MODE FIT” is ON)
λ
C = (
λ
'
2
+
λ
'
1
)/2 (when “MODE FIT” is OFF)
MODE displayed in the data area shall be the number of mode peaks between
λ
1
and
λ
2
.
Appendix 1 Data Calculation Algorithms for Spectrum Widths