Measurements and results
R&S
®
FSVA3000/ R&S
®
FSV3000
208
User Manual 1178.8520.02 ─ 08
Figure 5-37: Dynamic range for ACLR measurements on W-CDMA uplink signals as a function of the
mixer level
The level of the W-CDMA signal at the input mixer is shown on the horizontal axis, i.e.
the measured signal level minus the selected RF attenuation. The individual compo-
nents which contribute to the power in the adjacent channel and the resulting relative
level (total ACPR) in the adjacent channel are displayed on the vertical axis. The opti-
mum mixer level is -12
dBm. The relative adjacent channel power (ACPR) at an opti-
mum mixer level is -77
dBc. At a given signal level, the mixer level is set in 1
dB steps
with the 1
dB RF attenuator. Thus, the optimum range spreads from -10
dBm to
-14
dBm.
To set the attenuation parameter manually, the following method is recommended:
► Set the RF attenuation so that the mixer level (= measured channel power – RF
attenuation) is between -10
dBm and -14
dBm.
This method is automated with the "Auto Level" function. Especially in remote control
mode, e.g. in production environments, set the attenuation parameters correctly before
the measurement. That saves the time required for automatic setting.
To measure the R&S
FSV/A's intrinsic dynamic range for W-CDMA adjacent channel
power measurements, a filter which suppresses the adjacent channel power is
required at the output of the transmitter. A SAW filter with a bandwidth of 4
MHz, for
example, can be used.
Channel power and adjacent-channel power (ACLR) measurement
