Anritsu S412E User Manual page 44

3-4 Vector Network Analyzer Quick Start Guide
When you have Cal Correction on, you cannot increase the frequency range or the number of
points. You can, however, reduce the frequency range or decrease the number of points
without forcing the calibration to become invalid. When reducing the frequency range, the
LMR Master uses the appropriate points within the new frequency range that have correction
coefficients applied to them. In that case, you can observe that the number of points that are
being used for calibration correction are automatically reduced.
If you reduce only the number of points, then the frequency range is not changed. The
LMR Master finds a subset of the original points in the sweep that can be used. You can
therefore notice that the instrument may not use the exact number of points that you have
entered. It picks a specific number of points that allow the calibration correction to continue
to be valid. If you use the rotary knob, you will more easily find the available number of
points that can be set. For example, if you calibrated with 201 points, then you can observe
that you can reduce the number of points to 101, 68, 51, 41, and so forth.
If you change the source power setting, the calibration status is changed to "CAL: ON (?P)",
which indicates that source power has changed since the instrument was calibrated (from
Low to High, or from High to Low). In this case, the calibration may still be valid, but a new
calibration is recommended.
Another status information display that you may see is "CAL: ON (?T)" which indicates that
the instrument temperature has deviated by more than a set amount since the time that the
calibration was conducted. The calibration is most likely still valid, but a new calibration is
recommended. If you see "CAL: ON (X)" on the display, then this indicates that the
instrument temperature has deviated (since the time the calibration was conducted) by an
amount that has more than likely rendered the calibration invalid. When this occurs, a new
calibration is highly recommended before further measurements are conducted.
Only one calibration is available at one time. Performing a new calibration overwrites any
existing calibration. You can, however, store a measurement setup (with CAL), which also
stores the calibration. You can therefore have multiple calibrations available (as long as the
calibration settings and conditions continue to apply).
Existing Cal Info
The Cal Info submenu key is found in the Calibration main menu and lists the current
calibration settings.
3-8 PN: 10580-00318 Rev. P S412E UG