extinction
ratio
The
ratio
of
the
high-level
optical
power
to
the
low-level
optical
power
in
a
transmission
system
is
called
the
extinction
ratio
.
ferrule
A
tube
which
contains
the
optical
ber
.
The
ferrule
is
necessary
to
keep
the
ber
aligned.
rmkey
See
key.
rmware
Read-only
memory
(R
OM)
that
dictates
the
operating
characteristics
of
a
module
.
Each
rmware
version
has
an
identifying
date
code
.
The
local-oscillator
rmware
determines
the
operating
characteristics
of
the
spectrum
analyzer
.
T
o
learn
the
local-oscillator
rmware
date
code
,
press
4
MENU
5 ,
NNNNNNNNNNNNNN
Misc
,
NNNNNNNNNNNNNN
MORE
,
NNNNNNNNNNNNNNNNNNNNNNN
service
,
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
ROM
VERSION
.
The
date
code
for
the
display
rmware
is
displayed
when
the
display
is
powered
up
.
atness
Describes
the
amplitude
variations
corresponding
to
the
tuning
frequency
of
the
spectrum
analyzer
.
Flatness
of
61
dB
means
the
maximum
and
minimum
values
of
the
frequency
response
of
the
spectrum
analyzer
are
less
than
2-dB
apart.
frequency
stability
Refers
to
the
stability
of
the
spectrum
analyzer
.
Two
measures
of
frequency
stability
are
used,
short
term
and
long
term.
Residual
frequency
modulation
(FM)
and
noise
sidebands
are
a
measure
of
short-term
stability
.
Drift
is
a
measure
of
long-term
stability
.
FTZ
The
abbreviation
for
F
ernmeldewesen
T
echnischen
Zentrum.
This
is
the
part
of
the
German
post
oce
that
regulates
EMI
(electromagnetic
interference).
function
The
spectrum
analyzer
and
its
display
each
contain
a
unique
set
of
functions
that
are
executed
with
front-panel
keys
and
programming
commands
.
The
characteristics
of
these
functions
are
determined
by
the
rmware
in
the
local-oscillator
and
display
modules
.
User-dened
functions
are
created
by
the
user
with
the
FUNCDEF
or
A
CTDEF
command
and
may
be
executed
with
the
front-panel
keys
after
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
execute
dlp
is
pressed.
User-dened
functions
are
stored
in
internal
memory
and
remain
permanently
unless
they
are
altered
or
erased
by
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
PARTIAL
ERASE
or
certain
programming
commands
,
such
as
the
FORMA
T
,
LO
AD
,
PURGE,
DISPOSE,
PERASE,
ERASE,
A
CTDEF
,
RCLD
,
or
FUNCDEF
command.
Compatible
functions
are
programming
commands
that
have
the
ability
to
operate
on
other
analyzer
commands
,
called
predened
functions.
See
rmware,
user
memory,
and
reserved
memory.
gain
compression
Condition
where
change
in
spectrum-analyzer
response
is
not
directly
proportional
to
change
in
input-signal
level.
By
denition,
gain
compression
occurs
when
the
change
in
spectrum-analyzer
response
is
less
than
the
change
of
the
input-signal
level
by
a
specic
amount,
usually
1
dB.
Glossary-6
Summary of Contents for 70000 series
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