R&S FSW Series, Руководство пользователя

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Measurements and Results
R&S
®
FSW
202 User Manual 1173.9411.02 ─ 43
The R&S FSW sets the channel configuration to the W-CDMA standard for mobiles
with two adjacent channels above and below the transmit channel. The frequency
span, the resolution and video bandwidth and the detector are automatically set to
the correct values. The spectrum is displayed in the upper window and the channel
power, the level ratios of the adjacent channel powers and the channel configura-
tion in the lower window. The individual channels are displayed as bars in the
graph.
5. Set the optimal reference level and RF attenuation for the applied signal level using
the "Auto Level" function.
The R&S FSW sets the optimum RF attenuation and the reference level for the
power in the transmission channel to obtain the maximum dynamic range. The fol-
lowing figure shows the result of the measurement.
Figure 7-36: Measuring the relative adjacent channel power on a W-CDMA uplink signal
The R&S FSW measures the power of the individual channels. A root raised cosine
filter with the parameters
α
= 0.22 and chip rate 3.84 Mcps (= receive filter for W-
CDMA) is used as channel filter.
Optimum Level Setting for ACLR Measurements on W-CDMA Signals
The dynamic range for ACLR 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
FSW 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).
Channel Power and Adjacent-Channel Power (ACLR) Measurement