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7-61
Operating Concepts
Modifying Calibration Kits
• defines the standard type as a transmission line of specified length, for
calibrating transmission measurements.
• defines the standard type to be a load, but with an
arbitrary impedance (different from system Z0).
— allows you to specify the (arbitrary) impedance of the
standard, in ohms.
— defines the load as a fixed (not sliding) load.
— defines the load as a sliding load. When such a load is measured during
calibration, the analyzer will prompt for several load positions, and calculate the
ideal load value from it. Normally, arbitrary impedance standards are fixed rather
than sliding.
Any standard type can be further defined with offsets in delay, loss, and standard
impedance; assigned minimum or maximum frequencies over which the standard applies,
and defined as coax or waveguide. The softkey accesses the specify
offset menu (described next).
The softkey allows you to define a distinct label for each standard, so that
the analyzer can prompt you with explicit standard labels during calibration (such as
SHORT). The function is similar to defining a display title, except that the label is limited to
ten characters.
After each standard is defined, including offsets, the softkey will
terminate the standard definition.
Specify Offset Menu
The specify offset menu allows additional specifications for a user-defined standard.
Features specified in this menu are common to all five types of standards.
Offsets may be specified with any standard type. This means defining a uniform length of
transmission line to exist between the standard being defined and the actual measurement
plane. (Example: a waveguide short circuit terminator, offset by a short length of
waveguide.) For reflection standards, the offset is assumed to be between the measurement
plane and the terminating element of the standard (one-way only). For transmission
standards, the offset is assumed to exist between the two reference planes (in effect, the
offset is the thru). For both reflection and transmission, the offset is entered as a one-way
offset. Three characteristics of the offset can be defined: its delay (length), loss, and
impedance.
In addition, the frequency range over which a particular standard is valid can be defined
with a minimum and maximum frequency. This is particularly important for a waveguide
standard, since the minimum frequency is used to define the waveguide cutoff frequency.
Note that several band-limited standards can together be defined as the same "class" (see
“Specify Class Menu” on page 7-62). Then, if a measurement calibration is performed over
a frequency range exceeding a single standard, additional standards can be used for each
portion of the range.
Lastly, the standard must be defined as either coaxial or waveguide. If it is waveguide,
dispersion effects are calculated automatically and included in the standard model.
DELAY/THRU
ARBITRARY IMPEDANCE
TERMINAL IMPEDANCE
FIXED
SLIDING
SPECIFY OFFSET
LABEL STD
STD DONE (DEFINED)