Anritsu MS9740B - Page 191

5.6 Measuring Laser Diode Modules
5-41
5
Measurement Functions
Figure 5.6.2-3 Measurement of Noise at Noise Position
Point:
Noise level detection point when Detection Type is Point
Higher: Higher level at left side or right side of signal wavelength
Left: Signal left side (short wavelength side)
Right: Signal right side (long wavelength side)
(L+R)/2: Average level of Signal left and right sides
Area:
Fitting curve calculation range when Detection Type is Area
Fitting Curve: Type of fitting curve
Linear: Linear equation for noise linear data
f (λ) = aλ + b
Gauss: Binomial equation for noise log data
f (λ) = aλ
2
+ bλ + c
3rd POLY: Third-order polynomial equation for noise linear data
f (λ) = aλ
3
+ bλ
2
+ cλ + d
4th POLY: Forth-order polynomial equation for noise linear data
f (λ) = aλ
4
+ bλ
3
+ cλ
2
+ dλ + e
5th POLY: Fifth-order polynomial equation for noise linear data
f (λ) = aλ
5
+ bλ
4
+ cλ
3
+ dλ
2
+ eλ + f
Fitting Curve Display:
Fitting curve display setting
Off: Does not display fitting curve on screen
On: Displays fitting curve on screen
Area Type Area setting method for calculating fitting curve
Channel: Symmetrical area to Signal wavelength
User Specify: User specified range by left and right side of Signal
Wavelength
Wavelength (nm)
Level
(a) Noise Position Off
l
s
Left
Noise level
(b) Noise Position On
Right
Noise level
Wavelength (nm)
Level
l
s –
∆l l
s
l
s +
∆l
Left
Noise level
Right
Noise level