Anritsu MS9740B - Analyzing Single Spectrum Center Wavelength and Spectrum Width

Chapter 4 Changing Measurement Conditions
4-14
4.5.1 Analyzing Single Spectrum Center Wavelength and Spectrum
Width
1. Press
f1 Threshold
.
2. Select the cut level from
f1
to
f4
and enter the value using the rotary
knob or keypad. The cut level, which is an attenuator from the peak
level, can be used to calculate the spectrum width.
The cut level input range is 0.1 to 50 dB.
3. The cut level, center wavelength (λc) and spectrum width (Δλ)are
displayed.
Figure 4.5.1-1 Threshold Analysis
The center wavelength (λc) and spectrum width (Δλ)are calculated by the
following formula.
λc = (λ1 + λ2)/2
Δλ = λ2 – λ1
λ1: Shortest wavelength in all wavelengths crossed with the level
lowered cut level from the peak level
λ2: Longest wavelength in all wavelengths crossed with the level
lowered cut level from the peak level
If there are no crossing wavelengths with the cut level, the following
values are displayed:
λc: Center wavelength (Center)
Δλ: Wavelength difference between right and left sides (Span)
Cut level
Analysis result
display field