Rohde & Schwarz FSW43 - Page 319

Common Measurement Settings
R&S
®
FSW
319User Manual 1173.9411.02 ─ 19
6.2.2.1 Radio Frequency Input
The default input source for the R&S FSW is "Radio Frequency", i.e. the signal at the
RF INPUT connector on the front panel of the R&S FSW. If no additional options are
installed, this is the only available input source.
Radio Frequency State............................................................................................... 319
Input Coupling.............................................................................................................319
Impedance.................................................................................................................. 319
High-Pass Filter 1...3 GHz.......................................................................................... 320
YIG-Preselector...........................................................................................................320
Input Connector...........................................................................................................320
Radio Frequency State
Activates input from the RF INPUT connector.
Remote command:
INPut:SELect on page 866
Input Coupling
The RF input of the R&S FSW can be coupled by alternating current (AC) or direct cur-
rent (DC).
AC coupling blocks any DC voltage from the input signal. This is the default setting to
prevent damage to the instrument. Very low frequencies in the input signal may be dis-
torted.
However, some specifications require DC coupling. In this case, you must protect the
instrument from damaging DC input voltages manually. For details, refer to the data
sheet.
Remote command:
INPut:COUPling on page 865
Impedance
The reference impedance for the measured levels of the R&S FSW can be set to 50 Ω
or 75 Ω.
75 Ω should be selected if the 50 Ω input impedance is transformed to a higher impe-
dance using a 75 Ω adapter of the RAZ type (= 25 Ω in series to the input impedance
of the instrument). The correction value in this case is 1.76 dB = 10 log (75Ω/50Ω).
Data Input and Output