Rohde & Schwarz FPL1000 Series, User Manual

Page: 387 / 899

The Spectrum Application (RF Measurements)
R&S
®
FPL1000
387 User Manual 1178.3370.02 ─ 03
In "Manual" mode, you can set the RF attenuation in 5 dB steps down to 0 dB (with
option R&S FPL1-B22: in 1 dB steps). Other entries are rounded to the next integer
value. The range is specified in the data sheet. If the defined reference level cannot be
set for the defined RF attenuation, the reference level is adjusted accordingly and the
warning "limit reached" is displayed.
NOTICE! Risk of hardware damage due to high power levels. When decreasing the
attenuation manually, ensure that the power level does not exceed the maximum level
allowed at the RF input, as an overload may lead to hardware damage.
For details, see
Chapter 7.5.1.2, "RF Attenuation" , on page 383.
Remote command:
INPut:ATTenuation
on page 658
INPut:ATTenuation:AUTO
on page 659
Impedance
For some measurements, the reference impedance for the measured levels of the
R&S
FPL can be set to 50
Ω
or 75
Ω
.
Select 75
Ω
if the 50
Ω
input impedance is transformed to a higher impedance using a
75
Ω
adapter of the RAZ type. (That corresponds to 25
Ω
in series to the input impe-
dance of the instrument.) The correction value in this case is 1.76 dB = 10 log (75
Ω
/
50
Ω
).
This value also affects the unit conversion (see " Reference Level " on page 385).
Remote command:
INPut:IMPedance
on page 670
Preamplifier
If the (optional) internal preamplifier hardware is installed, a preamplifier can be activa-
ted for the RF input signal.
You can use a preamplifier to analyze signals from DUTs with low output power.
The input signal is amplified by 20 dB if the preamplifier option is activated.
Remote command:
INPut:GAIN:STATe
on page 660
7.5.3 Scaling the Y-Axis
The individual scaling settings that affect the vertical axis are described here.
Access : "Overview" > "Amplitude" > "Scale" tab
Or : AMPT > "Scale Config"
The remote commands required to define these settings are described in Chap-
ter 8.8.3, "Configuring the Vertical Axis (Amplitude, Scaling)" , on page 656.
Amplitude and Vertical Axis Configuration