Anritsu MS9740B - Calculation Method

5.8 Measuring Optical Amplifier (Wavelength Division Multiplex)
5-79
5
Measurement Functions
5.8.4 Calculation Method
This section explains the method for calculating the optical amplifier gain
and noise figure. The noise figure calculation method differs according to
the NF Select setting.
ISS Method: IEC calculation method
This performs the following calculation when the IN waveform (Pin(λ))
and OUT waveform (Pout(λ)) are gathered, to calculate the gain and noise
figure.
(1) For the IN waveform
(a) The peak is detected in accordance with the peak detection
setting (S.Level, Search Threshold), and the peak wavelengths
(W
i..n
) and peak levels (Pin
i..n
) are obtained.
(b) Fitting is applied in accordance with the fitting conditions
(Fitting Span, Masked Span, Fitting Curve or Point) for the IN
waveform, and the noise level’s estimated values (Nin
i..n
) are
obtained.
(2) For the OUT waveform
(a) The peak levels (Pout
i..n
) are obtained at the peak wavelengths
(W
i..n
).
(b) Fitting is applied in accordance with the fitting conditions
(Fitting Span, Masked Span, Fitting Curve or Point) for the
OUT waveform, and the noise level’s estimated values (Nout
i..n
)
are obtained.
Gain (G
i
) and ASE (Pase
i
) are obtained as follows, and the noise figure is
calculated with the NF formula.
i
ii
i
Pin
NoutPout
G
−
=
i
Nin⋅−=
iii
GNoutPase
ISS Method: Advanced Calculation Method
The steps up to obtaining the peak levels (Pin
i
, Pout
i
) and estimated
values for noise levels (Nin
i
, Nout
i
) for the IN and OUT waveforms are the
same as with IEC.
However the formulas for obtaining gain (G
i
) and ASE (Pase
i
) are as
follows, and the noise figure is calculated with the NF formula.
ii
ii
i
NinPin
NoutPout
G
−
−
=
ii
iiii
i
NinPin
NinoutP
Pase
−
⋅−⋅
=
PoutPin