6-9
Calibrating for Increased Measurement Accuracy
Calibration Considerations
NOTE The preset state of the instrument can be configured so that interpolated
error correction is on or off. Press
to configure
the preset state of interpolated error correction.
System performance is unspecified when using interpolated error correc tion. The q uality of
the interpolated error correction is dependent on the amount of phase shift and the
amplitude change between measurement points. If phase shift is no greater than 180° per
approximately five measurement points, interpolated error correction offers a great
improvement over uncorrected measurements. The accuracy of interpolated error
correction improves as the phase shift and amplitude change between adjacent points
decrease. When you use the analyzer in linear frequency sweep, perform the original
calibration with at least 30 points per 1 GHz of frequency span for greatest accuracy with
interpolated error correction.
Interpolated error correction is available in three sweep modes: linear frequency, power
sweep, and CW time.
NOTE If there is a valid correction array for a linear frequency sweep, this may be
interpolated to provide correction at the CW frequency used in power sweep
or CW time modes. This correction is part of the interpolated error-correction
feature.
Error-Correction Stimulus State
Error correction is only valid for a specific stimulus state, which you must select before you
start a correction. If you change any of the following parameters, you will invalidate the
correction and the analyzer will switch the correction off (unless the interpolated error
correction feature is activated):
• frequency range
• number of points
• sweep type
The error correction quality may be de gr aded (Cor changes to C∆), if you change the
following stimulus state parameters:
• sweep time
• system bandwidth
• output power
If correction is turned off or shows C∆, the original stimulus state can be recalled by, first,
turning interpolation off ( ), and toggling correction off and then on
().
System
CONFIGURE MENU
USER SETTINGS
PRESET SETTINGS
CAL INTERP ON off
INTERPOL ON off
CORRECTION ON off