User Manual

The Spectrum Application (RF Measurements)
R&S
®
FPL1000
278User Manual 1178.3370.02 ─ 03
For this measurement, the RMS detector is activated.
The carrier-to-noise measurements are only available in the frequency domain (span
>0).
Measurement process
Depending on whether the carrier is inside or outside the analyzed channel, the mea-
surement process for the carrier-to-noise ratio varies:
●
The carrier is outside the analyzed channel: In this case, it is sufficient to switch on
the desired measurement function and to set the channel bandwidth. The carrier/
noise ratio is displayed on the screen.
●
The carrier is inside the analyzed channel: In this case, the measurement must be
performed in two steps:
– First, perform the reference measurement by switching on either the C/N or the
C/N
0
measurement and waiting for the end of the next measurement run. The
fixed reference marker is set to the maximum of the measured carrier signal.
– Then, switch off the carrier so that only the noise of the test setup is active in
the channel. The carrier-to-noise ratio is displayed after the subsequent mea-
surement has been completed.
Frequency Span
The frequency span should be set to approximately 4 times the channel bandwidth in
order to measure the carrier-to-noise ratio correctly. This setting is defined automati-
cally by the "Adjust Settings" function.
7.2.4.2 Carrier-to-Noise Results
As a result of the carrier-to-noise measurement the evaluated bandwidth and the cal-
culated C/N ratio are displayed in the result window. The fixed reference marker is indi-
cated in the diagram.
Measurements and Results