Agilent Technologies 8510C, Operating And Programming Manual

Page: 240 / 391

Measurement Calibration
R/T T est Set (One-P ath) Calibration Error Models
Y ou may c ho ose S
11
Resp onse, S
21
Resp onse, S
11
1-P ort, or One-P ath 2-P ort calibration
error mo dels. Rev erse calibration may also b e p erformed (S
12
and S
22
resp onse and S
22
1-P ort), but in this case, the standards (op en, short, and load) are still connected to p ort 1.
During measuremen t, y ou m ust use care to ph ysically rev erse the test device and select the
appropriate parameter (S
11
or S
22
).
Use pro cedures similar to those listed for the S-P arameter test set but only connect standards
to P ort 1.
Response and 1-P ort
The reection/transmission test set cannot pro duce real-time error corrected measuremen ts
using the One-P ath 2-P ort error mo del b ecause the device under test m ust b e man ually
rev ersed for eac h measuremen t. F or this reason, the tec hnique of com bining the resp onse and
1-P ort error mo dels describ ed ab o v e is usually the quic k est w a y to measure a t w o-p ort device
on a reection/transmission test set where source and load match eects are not an imp ortant
factor in the accuracy of the measuremen t.
One-P ath 2-P ort
The One-P ath 2-P ort calibration error mo del is designed sp ecially for the
reection/transmission test set. It pro vides v ector error correction of directivit y ,
source match, reection and transmission signal path frequency resp onse, load match,
and isolation errors for S
11
, S
21
, S
12
, and S
22
. This pro cedure is similar to the F ull 2-P ort
calibration pro cedure describ ed previously for S-parameter test sets, except that all calibration
takes place with resp ect to P ort 1, and the device under test (and p ossibly the adapters if
used) m ust b e man ually rev ersed in the pro cess of measuring an y S-parameter.
This man ual rev ersal makes it imp ossible to obtain fully error-corrected data in real
time. Instead, pressing the softkey lab eled
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
PRESS TO CONTINUE con trols a measuremen t
pro cess that includes op erator prompts to connect the test device for forward and rev
erse
measuremen ts, nishing with the corrected data for the selected parameter display ed and
ready for data output. Pressing another parameter k ey either displays the corrected data for
the new parameter c hoice immediately , or restarts the measuremen t pro cess.
When load and source match eects are not ma jor error con tributors in the measuremen t, or
when y ou wish to view the real time resp onse of the device under test and are not concerned
with absolute measuremen t accuracy , use a com bination of S
11
1-P ort and S
22
1-P ort reection
calibrations with S
21
and S
12
frequency resp onse transmission calibrations, instead of the
One-P ath 2-P ort sequence.
Av eraging may b e used during measuremen t calibration. If y ou use Ramp sw eep during
the device measuremen t, a v eraging cannot b e used with correct results due to the need to
rep eatedly man ually rev erse the device. In Step sw eep, a v eraging can b e used with the usual
b enet.
Calibrating for System Measurements 8-25