Rohde & Schwarz FSW Series, User Manual

Page: 91 / 371

Configuration
R&S
®
FSW-K7
91 User Manual 1173.9240.02 ─ 17
Reference Level
Defines the expected maximum reference level. Signal levels above this value may not
be measured correctly, which is indicated by the "IF OVLD" status display ("OVLD" for
analog baseband or digitial baseband input).
The reference level is also used to scale power diagrams; the reference level is then
used as the maximum on the y-axis.
Since the R&S FSW hardware is adapted according to this value, it is recommended
that you set the reference level close above the expected maximum signal level to
ensure an optimum measurement (no compression, good signal-to-noise ratio).
Note that the "Reference Level" value ignores the Shifting the Display (Offset) . It is
important to know the actual power level the R&S FSW must handle.
Note that for input from the External Mixer (R&S FSW-B21) the maximum reference
level also depends on the conversion loss; see the R&S FSW I/Q Analyzer and I/Q
Input User Manual for details.
Remote command:
DISPlay[:
​
WINDow<n>]:
​
TRACe:
​
Y[:
​
SCALe]:
​
RLEVel
​
on page 234
Shifting the Display (Offset) ← Reference Level
Defines an arithmetic level offset. This offset is added to the measured level irrespec-
tive of the selected unit. The scaling of the y-axis is changed accordingly.
Define an offset if the signal is attenuated or amplified before it is fed into the
R&S
FSW so the application shows correct power results. All displayed power level
results will be shifted by this value.
Note, however, that the Reference Level value ignores the "Reference Level Offset". It
is important to know the actual power level the R&S FSW must handle.
To determine the required offset, consider the external attenuation or gain applied to
the input signal. A positive value indicates that an attenuation took place (R&S
FSW
increases the displayed power values) , a negative value indicates an external gain
(R&S
FSW decreases the displayed power values).
The setting range is ±200 dB in 0.01 dB steps.
Remote command:
DISPlay[:
​
WINDow<n>]:
​
TRACe:
​
Y[:
​
SCALe]:
​
RLEVel:
​
OFFSet
​
on page 235
Unit ← Reference Level
The R&S FSW measures the signal voltage at the RF input. In the default state, the
level is displayed at a power of 1 mW (= dBm). Via the known input impedance (50 Ω
or 75 Ω, see
"Impedance" on page 57), conversion to other units is possible. The fol-
lowing units are available and directly convertible:
●
dBm
●
dBmV
●
dBμV
●
dBμA
●
dBpW
●
Volt
●
Ampere
Input and Frontend Settings