Spectrum Measurements
R&S
®
ESRP
424
User Manual 1175.7445.02 ─ 08
5. Set up the adjacent channel power measurement with the fast ACLR mode.
a) Set "Fast ACLR" softkey to "On".
b) Press the "Adjust Ref Level" softkey.
The R&S
ESRP measures the power of the individual channels with zero span.
A root raised cosine filter with the parameters
α
= 0.22 and chip rate 3.84 Mcps
(= receive filter for 3GPP W-CDMA) is used as channel filter.
Figure 6-34: Measuring the adjacent channel power of a W-CDMA signal with the fast ACLR mode
Optimum Level Setting for ACP Measurements on W-CDMA Signals
The dynamic range for ACPR measurements is limited by the thermal noise floor, the
phase noise and the intermodulation (spectral regrowth) of the signal analyzer. The
power values produced by the R&S
ESRP due to these factors accumulate linearly.
They depend on the applied level at the input mixer. The three factors are shown in the
figure below for the adjacent channel (5 MHz carrier offset).
Advanced Measurement Examples