I
-
I
-
Making Measurements
Measuring Impedance Magnitude
How
the
Reflection
Measurement
Works
A reflection trace can be converted to equivalent parallel impedance using
the model and equations shown in Figure 3-26. In the formula shown in
Figure 3-26,
r
is the complex reflection coefficient. The complex impedance,
Znes,
is computed based on I’ and ZO. The analyzer displays the magnitude of
Znes.
This measurement assumes a two-terminal device, connected across the
analyzer’s REFLECTION port.
Reflection
(r)
I
fr
ZRef,
=
zo
.
-
i-r
Figure 3-26. Impedance Calculation for Reflection Measurements
3-63
-1