Rohde & Schwarz FPC Series, User Manual

Page: 182 / 419

Vector Network Analyzer
R&S
®
FPC
179 User Manual 1178.4130.02 ─ 07
Defining the cable length
The cable length is the sum of the start and stop distances you define for the measure-
ment.
If you do not know the exact length of the cable, define a length that is about 20 % to
50 % larger than the best estimate.
1. Press the "Freq" key to enter the frequency menu.
2. Select the "Start Distance" menu item to define the start of the measurement.
3. Select the "Stop Distance" menu item to define the stop of the measurement.
The maximum cable length that is suitable for measurements depends on the cable
attenuation. Because the test signal must be routed twice through the cable, the signal
reflected at the cable end arrives with twice the cable attenuation in attenuated form at
the input of the power divider. Dynamic range decreases with increasing cable length.
18.2 Frequency Configuration
Access : "Freq"
Access : "Setup" > "Config Overview" > "Stimulus" (selected settings)
Remote commands to configure the frequency:
●
Chapter 19.16.3, "Frequency" , on page 335
VNA measurements are done over a certain frequency range on a certain number of
discrete
measurement points . You can define the frequency range by defining a center
frequency and a start and stop frequency or a frequency span, similar to the spectrum
application.
The R&S FPC displays the frequency information on the x-axis (except for the DTF
measurement, which shows the cable length on the x-axis).
Frequency settings in the VNA application described elsewhere:
●
"Center Frequency": "Defining a center frequency" on page 94
●
"Start Frequency" and "Stop Frequency": Chapter 14.3.2, "Frequency Span" ,
on page 96
●
"Manual Span": Chapter 14.3.2, "Frequency Span" , on page 96
●
"Full Span": Chapter 14.3.2, "Frequency Span" , on page 96
(not available for DTF measurements)
●
"Signal Standard": Chapter 14.3.3, "Channel Tables" , on page 97
Defining the frequency range for DTF measurements
When you define the frequency range in the DTF measurement, it is best to first set the
span and then the center frequency.
In the DTF measurement, you can define the span manually or automatically.
1. Press the "Span" key to open the span menu.
Frequency Configuration