Technical data

5-15
Operating Concepts
Analyzer Display Formats
Figure 5-7. Group Delay Format
Smith Chart Format
The SMITH CHART, softkey displays a Smith chart format. Refer to Figure 5-8. This is used in reflection
measurements to provide a readout of the data in terms of impedance. The intersecting dotted lines on the
Smith chart represent constant resistance and constant reactance values, normalized to the characteristic
impedance, Z
0
, of the system. Reactance values in the upper half of the Smith chart circle are positive
(inductive) reactance, and those in the lower half of the circle are negative (capacitive) reactance. The
default marker readout is in ohms (
Ω) to measure resistance and reactance (R+jX). Additional marker
types are available in the Smith marker menu.
The Smith chart is most easily understood with a full scale value of 1.0. If the scale per division is less than
0.2, the format switches automatically to polar. If the characteristic impedance of the system is not 50
ohms, modify the impedance value recognized by the analyzer by pressing Cal, MORE, SET Z0, (the
impedance value) x1.
An inverted Smith chart format for admittance measurements is also available. This is shown in Figure 5-8.
Access this by selecting SMITH CHART, in the format menu, and pressing Marker Fctn, MKR MODE
MENU, SMITH MKR MENU, G+jB MKR. The Smith chart is inverted and marker values are read out in
siemens (S) to measure conductance and susceptance (G+jB).