HP 8712ES User Manual page 274

Calibrating for Increased Measurement Accuracy
Calibration Kits
C , C , C , C At high frequencies, an open rarely has perfect
0 1 2 3
reflection characteristics because fringing capacitance
causes phase shift that varies with frequency.
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
+ (C
frequency.
The terms in the equation are defined when specifying
the open as follows:
• C
• C
• C
• C
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."
6-28
2 3
*f ) + (C *f ) where f is the measurement
2 3
is used to enter the C
0
constant term of the third-order polynomial and is
expressed in Farads.
is used to enter the C
1
(Farads/Hz).
is used to enter the C
2
is used to enter the C
3
) + (C
0
term, which is the
0
term, expressed in F/Hz
1
term, expressed in F/Hz
2
term, expressed in F/Hz
3
ES User's Guide
*f)
1
2
.
3
.