HP 8753D - Page 368

Calibrating for
Non-Insertable Devices
A
test
device
having
the same
sex connector
on both
the input
and output
cannot be
connected
directly
into
a
transmission
test
conguration. Therefore
,the
device is
considered
to
be
noninsertable
,
and
one
of the
following calibration
methods must
be performed.
F
or
information
on
performing
measurement
calibrations,
refer to
Chapter 5,
\Optimizing
Measurement
Results
."
A
dapter
Removal
The
adapter
removal
technique
provides
a
means
to
accurately
measure
the
noninsertable
device
.
F
or
each
port,
a
separate
2-port
error
correction
needs
to
be
performed
to create
a
calibration
set.
The
adapter
removal
algorithm
uses
the
resultant
data
from
the
two
calibration
sets
and
the
nominal
electrical
length
of
the
adapter
to
compute
the
adapters
actual
S-parameters
.
This
data
is
then
used
to
generate
a
separate
third cal
set in
which the
forward
and
reverse
match
and
tracking
terms
are
as
if
P
ort
1 and
Port
2 could
be connected.
This
is
possible
because
the
actual
S-parameters
of
the
adapter
are
measured
with
great accuracy
,
thus
allowing
the
eects
of
the
adapter
to
be
completely
removed
when
the
third cal
set is
generated.
See
Chapter
5.
Matched
A
dapters
With
this
method,
you
use
two
precision
matched
adapters
which
are
\equal."
T
o
be
equal,
the
adapters
must
have
the
same
match,
Z
0
,
insertion
loss
,
and
electrical
delay
.
Modify
the
Cal
Kit
Thru
Denition
With
this
method
it
is
only
necessary
to
use
one
adapter
.
The
calibration
kit
thru
denition
is
modied
to
compensate
for
the
adapter
and
then
saved
as
a
user
kit.
However
,
the
electrical
delay
of
the
adapter
must
rst
be
found.
Application and Operation Concepts 6-101