HP 54750A, User Manual, Page: 170 / 478

The Digital Communications
Analysis Menus
Measure Eye Menu
N O T E
The dark cal routine requires that the dark signal level be on screen. If this level (for example , the
signal level when a laser is turned o) is not seen on the screen, the dark cal will fail.
K ey Path 4
Shift
5 4
Meas ey e
5
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
Extinction ratio...
NNNNNNNNNNNNNNNNNNNNNNNNNN
Dark cal
Extinction ratio can be displayed in one of three formats:
dB
%
ratio
The desired format is selected in the Extinction Ratio menu.
K ey Path 4
Shift
5 4
Meas ey e
5
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
Extinction ratio...
NNNNNNNNNNNNNNNNNNNN
Format ratio , decibel , or %
The ratio format calculates extinction ratio as:
r atio =
V
top
0 V
dar k
V
base
0 V
dar k
E xtinction r atio per cent = 100
V
base
0 V
dar k
V
top
0 V
dar k
E xtinction r atio dB = 10l og
V
t o p
0 V
dar k
V
b a s e
0 V
dar k
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