120 Keysig ht N9923-90001 User’s GuideCalibration for NA, CAT, and VVM ModesInterpolated Calibrations are only slightly less accurate than a calibrationperformed at the measurement settings. Learn more about the relativeaccuracy of FieldFox calibrations in “Cal ON ? – Questionable Accuracy” onpage 120.When a calibration that you performed is being interpolated, an asterisk isadded to the Cal annotation. For example: Cal ON U* is shown on the screenwhen the current Response or Mechanical cal is being interpolated. An * isnever added to a CalRdy.Cal ON ? – Questionable AccuracyWhen the Output Power, Interference Rejection, or IF BW (NA Mode ONLY)setting is changed AFTER performing a calibration, a question mark is added tothe Cal annotation. For example: Cal ON Q? is shown on the screen when thecurrent QuickCal is being interpolated. A ? is never added to CalRdy.The resulting measurement accuracy depends on how much the setting haschanged. For highest accuracy, recalibrate using the new settings.Compatible Mode CalibrationsThe FieldFox can have only ONE calibrat ion present for all modes. Because NA,CAT, and VVM modes are very similar, a calibration that is performed in onemode can also be applied in the other modes with the same type ofmeasurements (1-port or 2-port).To apply a Cal that was performed in a different mode, press Cal 5 then selectCal ON.Save the CalibrationAfter performing any type of calibration, you can save the FieldFox settingsalong with the calibration into a STATE (*.sta) file. These settings andcalibration can then be recalled as necessary. To learn how, see “Saving andRecalling Files” on page 192.CalReady PropertiesThere are several factory calibrations (CalReady) on every FieldFox. These canbe selected based on the type of DUT that you measure most often, and thecompromise that you prefer to make between measurement speed versusmeasurement accuracy. Remember, CalReady was performed at the test ports.Therefore, a CalReady calibration is most accurate when the DUT is directlyconnected to the test ports. Learn more in “CalReady” on page 104.This setting does NOT survive Preset or Power ON/OFF.— Press Cal 5 then More— Thenpress CalReady to toggle between the following selections:
