7- 8 Keysight N9912-90001 User’s Guide
Calibration for NA, CAT, and VVM Modes
Why and When to Calibrate
7-
How to turn Error Correction OFF
"Error Correction" is applying the results of a calibration to a measurement.
Error Correction is automatically turned ON after a calibration. You could turn
Error Correction OFF in order to see the effects of a calibration on the
measurement.
—Press Cal 5
then Error Correction ON OFF.
—Then Exit
or Esc.
— Cal OFF
is shown on the screen when Correction is OFF.
— Cal OFF*
is shown on the screen when switching from a 1-port
measurement to a 2-port measurement or vice-versa. Calibration for the
current measurement has NOT been performed.
Cal ON ? – Questionable Accuracy
If a change made by the user to the output power setting, or a change made
automatically by the FieldFox firmware makes accurate calibration
interpolation questionable, a question mark is added to the screen annotation
for all calibration states (Ex: CAL ON ?
). The resulting measurement accuracy
depends on how much the setting has changed. For optimum accuracy,
recalibrate using the new settings.
Compatible Mode Calibrations
Because CAT, NA, and VVM modes are very similar, a 1-port or 2-port
calibration that is performed in one mode is automatically applied in the other
modes. This occurs ONLY when modes have the same frequency data points,
have the same Power Level, and have the same IF BW. CAT Mode IF BW is 30
kHz and is NOT selectable.
Compatible 1-port and 2-port Calibrations
Typically, a 1-port calibration and a 2-port normalization can NOT be
maintained at the same time. The most recently performed calibration will
usually overwrite the other.
— In CAT mode, the 1-port measurement is Return Loss or DTF, and the
2-port measurement is Insertion Loss.
— In NA mode, the 1-port measurement is S11, and the 2-port measurement
is S21.
However, a 1-port calibration CAN coexist with a 2-port normalization ONLY
when BOTH of the following conditions occur:
1. A 1-port Cal already exists, then a Normalization Cal is performed. They can
NOT be performed in the reverse order.
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