Calibration for CAT, NA, and VVM Modes  61 
Calibration for CAT, NA, and VVM Modes 
The FieldFox performs a calibration automatically when powered ON and when 
Preset is performed. In addition, calibration can be performed manually. Key 
presses are identical in all of these Modes. 
In this Chapter 
Why and When to Calibrate ................................. 61 
Definitions .............................................................. 62 
Preset Calibration .................................................. 62 
QuickCal .................................................................. 62 
O,S,L Calibration ................................................... 63 
Normalize ................................................................ 64 
Compatible Mode Calibrations ............................ 65 
Compatible 1-port and 2-port Calibrations ....... 66 
Save a Calibration ................................................. 66 
Verify Calibration .................................................. 66 
Calibrate at the End of a Long Cable ................. 67 
Calibration Method Summary ............................. 68 
See Also 
Making 75 ohm Measurements at the FieldFox Supplemental Online Help: 
www.agilent.com/find/fieldsfoxsupport 
Why and When to Calibrate 
There are well-defined and understood systematic errors that are measured and 
calculated during the calibration process. These errors are caused by leakage 
signals inside the FieldFox, by the frequency response of the FieldFox receivers, 
and by reflections inside the FieldFox that interact with the DUT. After 
calibration, these errors are removed from subsequent measurements. 
To maintain highest measurement accuracy, perform a new calibration when any 
of the following changes occur: 
  When any of the following measurement settings change: Frequency Range, 
Power Level, and Resolution. Therefore, make these measurement settings 
before calibrating.  Increased Averaging and higher Resolution cause slower 
sweeps and slower calibration times. Learn about Interpolation and 
Questionable Accuracy on page 65. 
  When the FieldFox temperature changes more than about 10°F (5°C). Learn 
how to monitor the internal temperature on page 13. 
  When the connection to the DUT changes, requiring a different jumper cable or 
adapter.