Rohde & Schwarz FPC Series, User Manual

Page: 73 / 419

The Spectrum Application
R&S
®
FPC
70 User Manual 1178.4130.02 ─ 07
● Measuring the AM Modulation Depth ......................................................................79
● Measuring the Occupied Bandwidth ....................................................................... 81
● Working with the Spectrogram Result Display ........................................................ 84
14.2.1 Measuring the Channel Power of Continuously Modulated Signals
Access (measurement menu): "Meas" > "Measurement Mode" > "Channel Power"
Remote commands to control channel power measurements:
●
Chapter 19.12.1, "Measurements and Result Displays" , on page 232
Available with the optional "Advanced Measurements" application.
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 don't show in the results.
When measuring the spectrum within a channel, the R&S FPC uses a resolution band-
width that is small compared to the channel bandwidth. It then determines the total
power of the channel by integrating the results on the trace.
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.
Selecting the channel power measurement
1. Press the "Meas" key to open the measurement menu.
2. Select the "Measurement Mode" menu item to select the measurement.
3. Select the "Channel Power" menu item.
The R&S FPC starts to measure the channel power.
Two vertical lines indicate the channel bandwidth.
The channel power measurement shows the results and various other information
about the measurement in the diagram header.
●
Power / Max Power
Shows the power level measured within the channel. The label changes depending
on the
power mode you have selected.
●
Channel BW
Shows the currently selected channel bandwidth.
The diagram footer shows the currently selected center frequency and span .
● About the Measurement ..........................................................................................71
● Configuration ...........................................................................................................71
Measurements and Result Displays