EXFO IQS-12004B DWDM Passive Component Test System for IQS-500 - Manual (Page 421)

Definitions and Calculation Methods
DWDM Passive Component Test System 409
Measured BW1
In this method, BW1 is calculated based on measurement data.
For example, if you select a 1.0 dB bandwidth, the software will calculate
the wavelength range corresponding to the measured BW1. As shown in
the diagram, λ
lower
and λ
upper
correspond to the 1.0 dB cutoff wavelengths,
and this wavelength range will be used for the IL, ripple, and crosstalk
measurements.
Defined BW1
In this method, you specify to the software the wavelength range to use for
the evaluation. You will have to provide a specific wavelength (normally an
ITU wavelength) and a span centered at this wavelength.
As shown in the diagrams, the wavelength range for each case is different
and the resulting calculations will be different. The choice between the
two calculation methods is made in the Optical Ports Configuration
window, as explained in Configuring an Optical Port on page 39.
1.0 dB bandwidth (BW1)
Defined BW1 Measured BW1
ITU
λ
upper
λ
lower
λ
upper
λ
lower