HP 8530A, Руководство по эксплуатации и программированию, Страница: 241 / 439

Time Domain RCS Measurements
Do not attempt to gate out very large background reections , or subsequent measurements will
not be accurate .
Note
Be sure to turn OFF any existing calibration before making the gate settings for
a gated calibration. RCS calibration (gated or ungated) moves the target zone
to zero seconds in the Time Domain. Because of this , setting the gate while
calibration turned ON will put the gate in the wrong place . Since this will
produce a bad calibration, the HP 8530A will issue a warning if you attempt to
do this . If this ever happens , press TIME DOMAIN, GA TING, GA TE OFF , and
then return to the calibration by pressing CAL, RESUME CAL.
Using Gating During Subsequent Measurements
If gating is used during the calibration, HP recommends that it also be used in subsequent
calibrated RCS measurements . After calibration is nished, the receiver turns the gate OFF
automatically . It does this because the RCS calibration procedure shifts the target zone to
zero seconds , and the current gate would be in the wrong place . Move the Gate center to the
appropriate location around zero seconds before turning the gate back ON.
Eects of Gating on Background Calibrations
Gating has no eect on the isolation portion of any calibration, gated or ungated. It is applied
only to the dierence trace that is used when constructing the frequency response error term
during a gated RCS calibration.
13-16 Introduction to Time Domain RCS and
Antenna Measurements