Rohde & Schwarz FPC1000, User Manual

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The Spectrum Application
FPC1000
81
User Manual 1178.4130.02 ─ 02
2. Select the "Attenuator" menu item to open the attenuator menu.
3. The R&S FPC1000 provides several attenuation modes.
● "Manual Att <x> dB"
Defines the attenuation manually in 5 dB steps. The range is from 0 dB to
40 dB.
Manual attenuation is indicated by a blue dot in front of the "Att:" display in the
status bar.
Figure 9-8: Indicator of manual attenuation
● "Auto Low Distortion"
Selects an attenuation and gain that results in a good signal-to-noise ratio.
Thus, it reduces the display of spurious products. It also leads to an increased
display of the inherent noise (because of a higher attenuation).
See
Table 9-1 for the dependencies between reference level and applied
attenuation.
● "Auto Low Noise"
Selects an attenuation and gain that increases the sensitivity of the
R&S
FPC1000.
This mode gives a better impression of spurious products and is thus useful to
analyze signals whose level is near the noise level. However, the signal-to-
noise ratio in general can deteriorate.
See
Table 9-1 for the dependencies between reference level and applied
attenuation.
The current attenuation is indicated in the measurement settings.
Table 9-1: Dependencies of the selected reference levels and attenuation
Reference level
Preamplifier OFF
RF attenuation
Preamplifier ON
RF attenuation
Low noise Low distortion Low noise Low distortion
≤-30dBm 0 dB 0 dB 0 dB 0 dB
-29 dBm to -25 dBm 0 dB 0 dB 0 dB 5 dB
-24 dBm to -20 dBm 0 dB 0 dB 0 dB 10 dB
-19 dBm to -15 dBm 0 dB 5 dB 5 dB 15 dB
-14 dBm to -10 dBm 0 dB 10 dB 10 dB 20 dB
-9 dBm to -5 dBm 5 dB 15 dB 15 dB 25 dB
-4 dBm to 0 dBm 10 dB 20 dB 20 dB 30 dB
1 dBm to 5 dBm 15 dB 25 dB 25 dB 35 dB
6 dBm to 10 dBm 20 dB 30 dB 30 dB 40 dB
11 dBm to 15 dBm 25 dB 35 dB 35 dB 40 dB
16 dBm to 20 dBm 30 dB 40 dB 40 dB 40 dB
Amplitude Configuration
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