5-15
IM AQ6376-01EN
W
aveform Display
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App
Index
Example of Specific Usage
As shown below, this <1-kA/B→C k=*****.*> key or <1-kB/A→C k=*****.*> key may
be used to estimate the transmission efficiency from the reflection light spectrum, or
estimate the reflectivity from the transmission light spectrum for DUT.
(1) Estimating the transmission efficiency (trace C) from the reflection light spectrum
(trace A)
Transmitted light spectrum (TRACE C) = 1-k (TRACE A/TRACE B)
DUT (ex. filter)
TRACE C
TRACE B
TRACE A
Transmitted light
Reflected light
(2) Estimating the reflectivity (trace C) from the transmission light spectrum (trace A)
Reflected light spectrum (TRACE C) = 1-k (TRACE A/TRACE B)
DUT (ex. filter)
TRACE A
TRACE B
TRACE C
Transmitted light
Reflected light
The value of k is an absorption coefficient which is used in determining the DUT
reflectivity and transmission efficiency. Different algorithms are used depending on
whether transmission efficiency or reflectivity is estimated, so the k value also varies
accordingly.
The following equation can be used to determine “kr” and “kt” . In the equation, Pin is the
level prior to DUT input; Pout is the level after DUT input; Pre is the DUT reflection level; “kr”
is the absorption coefficient used to determine the reflectivity; and “kt” is the absorption
coefficient used to determine the transmission efficiency. (Each level is a linear value.)
Estimating the reflected light spectrum from the transmission light spectrum
k t = (Pin–Pre)/Pout
Estimating the transmission light spectrum from the reflected light spectrum
k r = (Pin–Pout)/Pre
5.5 Displaying Calculated Waveforms