Rohde & Schwarz R&S FSP Series, Operating Manual

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Operating Manual 1164.4556.12 - 06 2.7
R&S FSP Getting Started
Measuring the Spectra of Complex Signals
Fig. 2.11 Intermodulation-free range of the FSP3 as a function of level at the input mixer and the
set resolution bandwidth (useful signal offset = 1 MHz, DANL = -155 dBm /Hz, TOI = 12
dBm; typ. values at 2 GHz)
The optimum mixer level, i.e. the level at which the intermodulation distance is at its
maximum, depends on the bandwidth. At a resolution bandwidth of 10 Hz, it is
approx. –42 dBm and at 10 kHz increases to approx. -32 dBm.
Phase noise has a considerable influence on the intermodulation-free range at car-
rier offsets between 10 and 100 kHz (
Fig. 2.12 ). At greater bandwidths, the influence
of the phase noise is greater than it would be with small bandwidths. The optimum
mixer level at the bandwidths under consideration becomes almost independent of
bandwidth and is approx. –40 dBm.
Fig. 2.12 Intermodulation-free dynamic range of the FSP3 as a function of level at the input mixer
and of the selected resolution bandwidth (useful signal offset = 10 to 100 kHz, DANL = -
155 dBm /Hz, TOI = 12 dBm; typ. values at 2 GHz).
Distortion free Dynamic Range
(1 MHz carrier offset
)
-120
-110
-100
-90
-80
-70
-60
-50
-40
-60 -50 -40 -30 -20 -10
Mixer level /dBm
Dyn range /dB
RBW = 10
Hz
RBW = 10
kHz
RBW = 1
kHz
RBW = 100
Hz
T.O.I.
Thermal Noise
Distortion free Dynamic Range
(10 to 100 kHz carrier offset
)
-120
-110
-100
-90
-80
-70
-60
-50
-40
-60 -50 -40 -30 -20 -10
Mixer level /dBm
Dyn. range /dB
RBW = 10
Hz
RBW = 10
kHz
RBW = 1
kHz
RBW = 100
Hz