Spectrum Analyzer Mode
R&S
®
Cable Rider ZPH
181
User Manual 1321.0950.02 ─ 07
The R&S Cable Rider ZPH then selects the smallest possible VBW with regard to
the available step size.
●
Selecting the detector:
It is best to use the RMS detector. This detector correctly indicates the power irre-
spective of the characteristics of the signal to be measured. The whole IF envelope
is used to calculate the power for each measurement point. The IF envelope is
digitized using a sampling frequency which is at least five times the resolution
bandwidth which has been selected. Based on the sample values, the power is cal-
culated for each measurement point using the following formula:
with
S
i
= linear digitized video voltage at the output of the A/D converter
N = number of A/D converter values per measurement point
P
RMS
= power represented by a measurement point
When the power has been calculated, the power units are converted into decibels
and the value is displayed as a measurement point.
In principle, the sample detector would be possible as well. Due to the limited num-
ber of measurement points used to calculate the power in the channel, the sample
detector would yield less stable results.
8.1.5.1
Selecting a Standard
For more information on selecting a standard, see
Chapter 8.1.3.1, "Selecting a Stan-
dard"
,
on page 173.
8.1.5.2
Configuring the Measurement
In addition to creating and editing standards with the R&S InstrumentView software,
the R&S Cable Rider ZPH also provides functionality to set up a measurement configu-
ration.
Setting the number of transmission channels
1. Press the [MEAS] key.
2. Select the "Channel Settings" softkey.
The R&S Cable Rider ZPH opens a submenu to select the channel settings.
3. Select the "Tx Channels" menu item.
The R&S Cable Rider ZPH opens an input field to define the number of transmis-
sion channels.
4. Enter the number of transmission channels you need for the measurement.
Performing Spectrum Measurements
