Spectrum Analyzer Mode
R&S
®
Cable Rider ZPH
168
User Manual 1321.0950.02 ─ 07
Time domain
In the time domain, the R&S Cable Rider ZPH analyzes the characteristics of a signal
at a particular frequency over time. The span during time domain measurements is
zero (zero span mode). You can use time domain measurements, for example to moni-
tor the characteristics of a signal.
The horizontal axis shows the time, the vertical axis shows the signal levels.
To perform a time domain measurement, you have to set the span to zero manually.
8.1.2
Measuring the Channel Power of Continuously Modulated Signals
The channel power measurement selectively measures the power of modulated sig-
nals. Unlike a power meter that performs measurements over its entire frequency
range, the channel power measurement measures the power of a specific transmission
channel. Other signals in the frequency spectrum do not show in the results.
When measuring the spectrum within a channel, the R&S Cable Rider ZPH uses a res-
olution bandwidth that is small compared to the channel bandwidth. It then determines
the total power of the channel by integrating the results on the trace. The R&S Cable
Rider ZPH takes the following parameters into account:
●
display mode (absolute or relative)
●
detector
●
resolution bandwidth
That means that you can compare the result to the result that would have been
obtained from a thermal power meter. The small resolution bandwidth acts like a nar-
row channel filter and so prevents out-of-channel emissions from affecting the result.
1. Press the [MEAS] key.
2. Select the "Meas Mode" key.
The R&S Cable Rider ZPH opens a submenu to select the measurement mode.
3. Select the "Channel Power" menu item.
The R&S Cable Rider ZPH starts to measure the channel power.
4. By default, the 3GPP WCDMA standard is active. Two vertical lines show the chan-
nel bandwidth.
Performing Spectrum Measurements
