Common Measurement Settings
R&S
®
FSW
316
User Manual 1173.9411.02 ─ 19
Microbutton action
You can define an action to be performed by the R&S
FSW when the probe's microbut-
ton (if available) is pressed. Currently, a single data acquisition via the probe can be
performed simply by pressing the microbutton.
Impedance and attenuation
The measured signal from the probe is attenuated internally by the probe's specific
attenuation. For probe signals that are redirected to the RF path, the attenuation is
compensated using a transducer (see
"Frequency sweep measurements on probe
on page 314). The reference level is adjusted automatically.
For analog baseband input, the attenuation is compensated without a transducer. In
this case, higher levels are available for the full scale level.
A fixed impedance of 50
Ω
is used for all probes to convert voltage values to power
levels.
6.2.1.4
Input from Noise Sources
The R&S
FSW provides a connector (NOISE SOURCE CONTROL) with a voltage sup-
ply for an external noise source. By switching the supply voltage for an external noise
source on or off in the firmware, you can activate or deactive the device as required.
External noise sources are useful when you are measuring power levels that fall below
the noise floor of the R&S
FSW itself, for example when measuring the noise level of
an amplifier.
In this case, you can first connect an external noise source (whose noise power level is
known in advance) to the R&S
FSW and measure the total noise power. From this
value you can determine the noise power of the R&S
FSW. Then when you measure
the power level of the actual DUT, you can deduct the known noise level from the total
power to obtain the power level of the DUT.
The noise source is controlled in the "Output" settings, see
6.2.1.5
Receiving and Providing Trigger Signals
Using one of the variable TRIGGER INPUT/OUTPUT connectors of the R&S
FSW, the
R&S
FSW can use a signal from an external reference as a trigger to capture data.
Alternatively, the internal trigger signal used by the R&S
FSW can be output for use by
other connected devices. Using the same trigger on several devices is useful to syn-
chronize the transmitted and received signals within a measurement.
For details on the connectors see the R&S
FSW "Getting Started" manual.
External trigger as input
If the trigger signal for the R&S
FSW is provided by an external reference, the refer-
ence signal source must be connected to the R&S
FSW and the trigger source must be
defined as "External" on the R&S
FSW.
Data Input and Output
