HP 8753D - Page 273

Pre-Raw
Data Arrays
These
data arrays
store
the
results
of
all
the
preceding
data
processing
operations
.
(Up to
this
point, all
processing
is
performed
real-time
with
the
sweep
by
the
IF
processor
. The
remaining
operations are
not
necessarily
synchronized
with
the
sweep
,
and
are
performed
by
the main
processor
.)
When
full
2-port
error
correction
is
on,
the
raw
arrays
contain
all
four
S-parameter measurements
required for
accuracy
enhancement.
When
the
channels
are
uncoupled
(
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COUPLED
CH
OFF
),
there
may
be
as
many
as
eight
raw
arrays
.
These
arrays
are
directly
accessible
via HP-IB
. Notice
that the
numbers
here
are
still
complex
pairs
.
Raw
Arrays
Raw
arrays
contain the
pre-raw data
which has
sampler and
attenuator
oset
applied.
Vector
Error-correction (A
ccuracy Enhancement)
Error-correction is
performed next,
if a
measurement
calibration
has
been
performed
and
correction is
activated. Error-correction
removes repeatable
systematic
errors
(stored
in
the
error coecient
arrays) from
the
raw
arrays
.
This
can
vary
from
simple
vector
normalization
to
full
12-term
error-correction.
The
results
of
error-correction
are
stored
in
the
data arrays
as complex
number pairs
.
These
are
subsequently
used
whenever
correction
is
on,
and
are accessible
via HP-IB
.
If
the
data-to-memory
operation
is
performed,
the
data
arrays are
copied into
the memory
arrays
.
Trace
Math
Operation
This
operation
selects
either
the data
array
,
memory
array
,
or
both
to
continue
owing
through
the
data
processing
path.
In
addition, the
complex
ratio
of
the
two
(data/memory)
or
the
dierence
(data
0
memory)
can
also
be selected.
If
memory
is
displayed,
the
data
from
the
memory
arrays
goes
through
exactly
the
same
processing
ow
path
as
the
data
from
the
data
arrays.
Gating (Option
010
Only)
This digital
ltering operation
is
associated
with
time
domain
transformation.
Its
purpose
is
to
mathematically
remove
unwanted
responses
isolated
in
time
.
In
the
time
domain,
this
can
be
viewed
as
a
time-selective
bandpass
or
bandstop
lter
.
(If
both
data
and
memory are
displayed,
gating
is
applied
to
the
memory
trace
only
if
gating
was
on
when
data
was stored
into
memory
.)
The Electrical Delay Block
This block involves adding or
subtracting phase in proportion to frequency
. This is equivalent
to \line-stretching" or articially moving the
measurement reference plane
. This block also
includes the eects of port extensions as
well as electrical delay
.
Conversion
This converts the measured S-parameter data to the equivalent complex impedance (Z) or
admittance (Y) values, or to inverse S-parameters (1/S).
Transform (Option 010 Only)
This transform converts frequency domain information into the time domain when it is
activated . The results resemble time domain reectometry (TDR) or impulse-response
measurements. The transform uses the chirp-Z inverse fast Fourier transform (FFT) algorithm
to accomplish the conversion. The windowing operation, if enabled, is performed on the
6-6 Application and Operation Concepts