Agilent Technologies 4395A - Page 420

Calibration
for
Network
Measurement
Frequency
Response
(Tracking)
This
is
the
vector
sum
of
all
test
setup
variations
in which
magnitude and
phase change
as a
function
of
frequency
.
This
includes
variations contributed
by signal
separation devices
, test
cables
,
and
adapters
,
and
variations between
the reference
and test
signal paths
.This
error is
a
factor
in
both
transmission
and
reection
measurements.
F
or
further
explanation
of
systematic
error
terms
and
the
way they
are combined
and
represented
graphically
in
error
models
,
see the
later section,
titled A
ccuracy Enhancement
Fundamentals
-
Characterizing
Systematic
Errors
.
Compensation
for
Measurement
Errors
There
are
twelve
dierent
error
terms
for
a
two-port
measurement
that
can
be
corrected
by
accuracy
enhancement
in
the
analyzer
.
These
are
directivity
,
source
match,
load
match,
isolation,
reection
tracking,
and
transmission
tracking,
each
in
both
the
forward
and
reverse
direction.
The
analyzer
has
several
dierent
measurement
calibration
routines
to
characterize
one
or
more
of
the
systematic
error
terms
and
remove
their
eects
from
the
measured
data.
The
procedures
range
from
a
simple
frequency
response
calibration
to
a
full
two-port
calibration
that
eectively
removes
all
twelve
error
terms
.
The Response
Calibration eectively
reduces the
frequency
response
errors
of
the
test
setup
for reection
or transmission
measurements.
This calibration
procedure
may
be
adequate
for
measurement
of
well-matched
low-loss
devices
.
This
is
the
simplest
error
correction
to
perform,
and
should
be
used
when
extreme
measurement
accuracy
is
not
required.
The
Response
and
Isolation
Calibration
eectively
removes
frequency
response
and
crosstalk
errors
in
transmission
measurements
,
or
frequency
response
and
directivity
errors
in
reection
measurements
.
This
procedure
may
be
adequate
for
measurement
of
well-matched
high-loss
devices
.
The
S
11
and
S
22
One-P
ort
Calibration
procedures
provide
directivity
,
source
match,
and
frequency
response
vector
error
correction
for
reection
measurements
.
These
procedures
provide
high
accuracy
reection
measurements
of
one-port
devices
or
properly
terminated
two-port
devices
.
The
Full
Two-P
ort
Calibration
provides directivity
, source
match, load
match, isolation,
and
frequency
response
vector
error
correction,
in
both forward
and reverse
directions,
for
transmission
and
reection
measurements
of
two-port
devices
. This
calibration provides
the
best
magnitude
and
phase
measurement
accuracy
for both
transmission and
reection
measurements
of
two-port
devices
,
and
requires
an S-parameter
test set.
The
One-P
ath
Two-P
ort
Calibration
provides
directivity
,
source match,
load
match,
isolation,
and frequency response vector error correction in one direction. It is used for high accuracy
transmission and reection measurements using a transmission/reection test kit, such as the
87512A, B . (The DUT must be manually reversed between sweeps to accomplish measurements
in both the forward
and reverse directions
.)
All the calibration procedures described
above are accessed from the
4
CAL
5 key.
A-44 Basic Measurement Theory