R&S ZNH, User Manual

Page: 116 / 369

Cable and Antenna Test Mode
R&S
®
ZNH
109 User Manual 1334.5985.02 ─ 02
● Smith Chart ........................................................................................................... 117
● Phase Measurement ............................................................................................. 119
● Calibrating Measurements .................................................................................... 120
7.1.1 Reflection Measurements
The reflection measurement (S11, S22) is a good way to get an idea if the transmission
system works properly. If unusual amounts of signal power are being reflected, you can
guess that there is something wrong in the system.
A reference signal is transmitted along the transmission system, and this signal is
reflected back by a discontinuity along the transmission line, usually by an impedance
mismatch. This reflected signal is measured and compared with the reference signal to
determine the loss of power.
The reflection measurement can be performed in the following measurement formats:
●
Magnitude (return loss in dB)
Return loss is power loss in dB, measured over the specified frequency range of
the transmission system. The return loss in dB is the default measurement format
in the reflection measurement.
●
SWR
The standing wave ratio, SWR provides the ratio of the maximum and minimum AC
voltages along the transmission line caused by the reflections.
●
Chapter 7.1.6, "Phase Measurement" , on page 119
●
Chapter 7.1.5, "Smith Chart" , on page 117
1. Press [MEAS] key
2. Select "Return Loss" softkey.
By default, the return loss "RL" is selected for reflection measurement.
The R&S
ZNH starts the reflection measurement with default measurement format
over its entire frequency range.
3. Alternatively, select "RL +Trans" for combine measurement .
The R&S ZNH displays the combine measurements over its entire frequency
range.
4. To perform S22 measurement, select "Port 2" menu item from "Driving Port" soft-
key.
The R&S
ZNH starts the S22 reflection measurement.
5. To change the measurement format, press [FORMAT] key.
The R&S ZNH displays the available measurement formats for "Return Loss" mea-
surement.
6. Select "db Mag", "SWR", "Phase" or "Smith" softkey.
The R&S ZNH starts the reflection measurement over its entire frequency range
with the selected measurement format.
Performing Cable and Antenna Measurements