R&S FSW Series, Руководство пользователя

Страница: 369 / 1450

Common Measurement Settings
R&S
®
FSW
369 User Manual 1173.9411.02 ─ 43
The impedance conversion does not affect the level of the output signals (such as IF,
video, demod, digital I/Q output)
"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:
INPut<ip>:IMPedance
on page 1071
INPut<ip>:IMPedance:PTYPe
on page 1071
For Analog Baseband input:
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:
INPut<ip>:DPATh
on page 1069
High Pass Filter 1 to 3 GHz
Activates an additional internal high-pass filter for RF input signals from 1 GHz to
3 GHz. This filter is used to remove the harmonics of the analyzer to measure the har-
monics for a DUT, for example.
This function requires an additional hardware option.
(Note: for RF input signals outside the specified range, the high-pass filter has no
effect. For signals with a frequency of approximately 4
GHz upwards, the harmonics
are suppressed sufficiently by the YIG-preselector, if available.)
Remote command:
INPut<ip>:FILTer:HPASs[:STATe]
on page 1070
YIG-Preselector
Activates or disables the YIG-preselector, if available on the R&S FSW.
Data Input and Output