Technical data

5-12
Operating Concepts
S-Parameters
measurements be taken with all test device ports properly terminated.
The Electrical Parameters Menu
The Electrical Parameters menu allows you to define the input ports and test set direction for S-parameter
measurements. The analyzer automatically switches the direction of the measurement according to the
selections you made in this menu. Therefore, the analyzer can measure all four S-parameters with a single
connection. The S-parameter being measured is labeled at the top left corner of the display.
The Electrical Parameters menu contains the following softkeys:
• Refl: FWD S11 (A/R),
• Trans: FWD S21 (B/R),
• Trans: REV S12 (A/R),
• Refl: REV S22 (B/R),
• ANALOG IN Aux Input,
• CONVERSION [ ], accesses the conversion menu.
• INPUT PORTS, accesses the input ports menu.
Analog In Menu
This menu allows you to monitor voltage and frequency nodes, using the analog bus and internal counter.
Conversion Menu
This menu converts the measured reflection or transmission data to the equivalent complex impedance (Z)
or admittance (Y) values. This is not the same as a two-port Y or Z parameter conversion, as only the
measured parameter is used in the equations. Two simple one-port conversions are available, depending on
the measurement configuration.
An S
11
or S
22
trace measured as reflection can be converted to equivalent parallel impedance or
admittance using the model and equations shown in Figure 5-3.
Figure 5-3. Reflection Impedance and Admittance Conversions
S-Parameter Definition Test Set Description Direction
S
11
b
1
/a
1
a
2
= 0 Input reflection coefficient FWD
S
21
b
2
/a
1
a
2
= 0 Forward gain FWD
S
12
b
1
/a
2
a
1
= 0 Reverse Gain REV
S
22
b
2
/a
2
a
1
= 0 Output reflection coefficient REV