HP HP 8712ET, User Manual, Page: 247 / 480

ET User’s Guide 6-21
Calibrating for Increased Measurement Accuracy
Calibration Kits
These effects are impossible to eliminate, but the
calculation built into the analyzer includes an
open-circuit capacitance model. This capacitance model
is a third-order polynomial as a function of frequency,
where the polynomial coefficients are user-definable.
The capacitance model equation is: C(f) = (C
0
) + (C
1
*f)
+ (C
2
*f
2
) + (C
3
*f
3
) where f is the measurement
frequency.
The terms in the equation are defined when specifying
the open as follows:
• C
0
is used to enter the C
0
term, which is the
constant term of the third-order polynomial and is
expressed in Farads.
• C
1
is used to enter the C
1
term, expressed in F/Hz
(Farads/Hz).
• C
2
is used to enter the C
2
term, expressed in F/Hz
2
.
• C
3
is used to enter the C
3
term, expressed in F/Hz
3
.
For further information on calibration kits and determining standard
characteristics, refer to HP Product Note 8510-5A (HP Publication
No. 5956-4352). To view this product note on the Web, go to
http://www.tmo.hp.com and select “Application Note Library.”
Step 2: Create a
User-Defined
Calibration Kit A user-defined calibration kit can be created by either of these two
methods:
• Method A: use the softkeys under the Modify Kit menu.
This method provides a convenient and quick way to modify
calibration kit standards. Use this method during the development of
new calibration kit standards.
• Method B: use an ASCII file.
This method provides a way to manage calibration kit descriptions in
separate files. Use this method to keep permanently filed descriptions
of your calibration kits.