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Pre-Raw Data Arrays
These data arrays store the results of
ail
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
(~~~~~~~~:~~~~,
there may be as many as eight raw arrays. These arrays are
;;;,.;....s..s
. . . . . . . . . . . .
...: ;;;~;.:;::.:....:
.A..
..u
. . . . . . .
..s....i
::.
::.,
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 offset applied.
Vector Error-correction(Accuracy
-cement)
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 coefficient 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 flowing through
the data processing path. In addition, the complex ratio of the two (data/memory) or the
difference (data-memory) can
also
be selected. If memory is displayed, the data from the
memory arrays goes through exactly the same processing flow path as the data from the data
arrays.
Gating (Option 010 Only)
This digital filtering 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
filter. (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 artificially moving the measurement reference plane. This block
also
includes the effects 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 (l/S).
6-6 Application and Operation Conwpts