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Chapter 10 Using RFoCPRI Analyzer
Configuring test parameters
Enabling auto leveling
It is normal to see higher levels of RSSI in CPRI spectrum than you have seen in RF
spectrum, as the digital signal has a different gain level from RF's. If you use the Auto
Leveling feature and enter the Noise Figure (NF) for the system to be tested, the instru-
ment calculates an offset that compensates the digital gain of RRH and applies it to the
spectrum automatically to displace the level of spectrum to a known RSSI power even
though its accuracy cannot be guaranteed. Offset calculation for Auto Leveling is based
on the following:
Auto Level offset = (Noise Floor of RFoCPRI) – (Ideal Noise Floor of RRH)
where (Idea Noise Floor) = N.F (RRH) + Thermal Noise + 10log (RBW)
To enable auto leveling
1
Tap Menu > Amp/Scale > Auto leveling.
A calculated level of offset without NF is applied as the external offset and the
user input field is activated for entry of the noise figure value.
2
Enter a noise figure value using the on-screen keyboard.
3
Tap Apply to complete the entry.
A new external value offset value appears in the External Offset menu box.
4
Tap External Offset to Off. Auto Leveling is turned off.
Figure 163
enabled.
Page 358
NOTE
Having the noise figure factored in the offset calculation for Auto Leveling will
enable you to view the CPRI spectrum closer to what you view in the RF spec-
trum. If you do not know the noise figure, you can skip this noise figure setting.
and
Figure 164
show an example of before and after Auto Leveling is
SPA06MA-O User's Guide
22145360, R005
April 2021
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