The Digital Communications
Analysis Menus
Measure Eye Menu
NOTE
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.
Key Path
4
Shift
54
Meas eye
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
N
N
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
N
N
N
N
N
Extinction
ratio...
N
N
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
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
dark
E xtinction r atio dB
=10
log
V
top
0
V
dark
V
base
0
V
dark
6-34