Common Measurement Settings
R&S
®
FSVA3000/ R&S
®
FSV3000
313
User Manual 1178.8520.02 ─ 01
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:
Impedance
The R&S
FSV/A has an internal impedance of 50
Ω
. However, some applications use
other impedance values. In order to match the impedance of an external application to
the impedance of the R&S
FSV/A, an
impedance matching pad
can be inserted at the
input. If the type and impedance value of the used matching pad is known to the
R&S
FSV/A, it can convert the measured units accordingly so that the results are cal-
culated correctly.
(See
The impedance conversion does not affect the level of the output signals (such as IF,
video, demod)
"50
Ω
"
(Default:) no conversion takes place
"75
Ω
"
The 50
Ω
input impedance is transformed to a higher impedance
using a 75
Ω
adapter of the selected "Pad Type": "Series-R" (default)
or "MLP" (Minimum Loss Pad)
"User"
The 50
Ω
input impedance is transformed to a user-defined impe-
dance value according to the selected "Pad Type": "Series-R"
(default) or "MLP" (Minimum Loss Pad)
Remote command:
Direct Path
Enables or disables the use of the direct path for small frequencies.
In spectrum analyzers, passive analog mixers are used for the first conversion of the
input signal. In such mixers, the LO signal is coupled into the IF path due to its limited
isolation. The coupled LO signal becomes visible at the RF frequency 0
Hz. This effect
is referred to as LO feedthrough.
To avoid the LO feedthrough the spectrum analyzer provides an alternative signal path
to the A/D converter, referred to as the
direct path
. By default, the direct path is
selected automatically for RF frequencies close to zero. However, this behavior can be
disabled. If "Direct Path" is set to "Off" , the spectrum analyzer always uses the analog
mixer path.
"Auto"
(Default) The direct path is used automatically for frequencies close
to zero.
"Off"
The analog mixer path is always used.
Remote command:
YIG-Preselector
Activates or disables the YIG-preselector, if available on the R&S
FSV/A.
Data Input and Output
