Rf Input - Keysight x-series User Reference Manual

4 Input/Output Functions
Input/Output
by one of the three ways:
• by using the Restore Input/Output Defaults key on the first page of the input/output menu,
• by using the System->Restore System Defaults->Input/Output Settings or,
• by using the System -> Restore System Defaults->All. Also, they survive a Preset and a Power cycle.
A very few of the Input/Output settings do respond to a Mode Preset; for example, if the Calibrator is on it
turns off on a Preset, and if DC coupling is in effect it switches to AC on a Preset. These exceptions are
made in the interest of reliability and usability, which overrides the need for absolute consistency.
Exceptions are noted in the SCPI table for the excepted functions.

RF Input

Selects the front-panel RF input port to be the analyzer signal input. If RF is already selected, pressing this
key accesses the RF input setup functions.
Key Path
Example
Couplings
Readback
Initial S/W Revision
Modified at S/W Revision
Input Z Correction
Sets the input impedance for unit conversions. This affects the results when the y-axis unit is voltage or
current units (dBmV, dBµV, dBµA, V, A), but not when it is power units (dBm, W). The impedance you select
is for computational purposes only, since the actual impedance is set by internal hardware to 50 ohms.
Setting the computational input impedance to 75 ohms is useful when using a 75 ohm to 50 ohm adapter to
measure a 75 ohm device on an analyzer with a 50 ohm input impedance.
There are a variety ways to make 50 to 75 ohm transitions, such as impedance transformers or minimum
loss pads. The choice of the solution that is best for your measurement situation requires balancing the
amount of loss that you can tolerate with the amount of measurement frequency range that you need. If
you are using one of these pads/adaptors with the Input Z Corr function, you might also want to use the
Ext Gain key. This function is used to set a correction value to compensate for the gain (loss) through your
pad. This correction factor is applied to the displayed measurement values.
152
Input/Output
[:SENSe]:FEED RF
The act of connecting the U7227A USB Preamplifier to one of the analyzer's USB ports will cause
the Input to automatically switch to the RF Input. If the RF Calibrator is on, it is turned off.
Subsequently disconnecting the USB Preamp from USB does not change the Input selection nor
restore the previous selection.
The RF input port, RF coupling, and current input impedance settings appear on this key as:
"XX, YY, ZZ" where
XX is RF, RF2, RFIO1, RFIO2, depending on what input is selected (only appears on analyzers with
multiple RF inputs)
YY is AC or DC
ZZ is 50Ω or 75Ω
Prior to A.02.00
A.14.00
EMI Receiver Mode Reference