Technical data

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Operating Concepts
Electrical Calibration Kit Modifications
The theoretical power reflected is 100%. However, this factor can be adjusted from 0% to
100% to account for any practical reflector being used in the calibration.
Electrical Calibration Kit Modifications
Modifying electrical calibration kits is necessary only if unusual standards (such as in TRL*) are used or
the very highest accuracy is required. Unless a calibration kit model is provided with the calibration devices
used, a solid understanding of error-correction and the system error model are absolutely essential to
making modifications. You may use modifications to a predefined calibration kit by modifying the kit and
saving it as a user kit. The original predefined calibration kit will remain unchanged.
Before attempting to modify calibration standard definitions, you should read Application Note 8510-5A to
improve your understanding of modifying calibration kits. The part number of this application note is
5956-4352. Although the application note is written for the 8510 family of network analyzers, it also applies
to this network analyzer.
Several situations exist that may require a user-defined calibration kit:
• A calibration is required for a connector interface different from the four default calibration kits.
(Examples: SMA, TNC, or waveguide.)
• A calibration with standards (or combinations of standards) that are different from the default
calibration kits is required. (Example: Using three offset shorts instead of open, short, and load to
perform a 1-port calibration.)
• The built-in standard models for default calibration kits can be improved or refined. Remember that the
more closely the model describes the actual performance of the standard, the better the calibration.
(Example: The 7 mm load is determined to be 50.4
Ω instead of 50.0 Ω.)
Definitions
The following are definitions of terms:
• A "standard" (represented by a number 1-8) is a specific, well-defined, physical device used to
determine systematic errors. For example, standard 1 is a short in the 3.5 mm calibration kit. Standards
are assigned to the instrument softkeys as part of a class.
• A standard "type" is one of five basic types that define the form or structure of the model to be used
with that standard (short, open, load, delay/thru, and arbitrary impedance); standard 1 is of the type
short in the 3.5 mm calibration kit.
• Standard "coefficients" are numerical characteristics of the standards used in the model selected. For
example, the offset delay of the short is 32 ps in the 3.5 mm calibration kit.
• A standard "class" is a grouping of one or more standards that determines which of the eight standards
are used at each step of the calibration. For example, standard number 2 and 8 usually makes up the
S
11
A reflection class, which for type-N calibration kits are male and female shorts.
Verify Performance
Once a measurement calibration has been generated with a user-defined calibration kit, its performance
should be checked before making device measurements. To check the accuracy that can be obtained using
the new calibration kit, a device with a well-defined frequency response (preferably unlike any of the
standards used) should be measured. The verification device must not be one of the calibration standards:
measurement of one of these standards is merely a measure of repeatability. To achieve more complete
verification of a particular measurement calibration, accurately known verification standards with a diverse