Measurements and Results
R&S
®
FSW
355
User Manual 1173.9411.02 ─ 43
Evaluating the measurement
Check the Result Summary to detect exceeded limit values.
Zoom into the diagram at the conspicuous frequency for more details.
If necessary, decrease the span to the area in which irregular values occurred and
repeat the measurement.
7.13.8
Optimizing and Troubleshooting EMI Measurements
If the results do not meet your expectations, try the following methods to optimize the
measurement:
Number of sweep points
The resolution bandwidth should cover at least one sweep point (more is better). If this
condition is not met, signals or interferences could be missed during refined measure-
ment of narrowband interferers. See
Chapter 7.13.3.3, "Frequency Resolution - Sweep
If the distance between two sweep points is larger than RBW/3, a warning is displayed
in the status bar ("Increase Sweep Points" or "RBW").
Dwell time
Consider the following when defining the dwell time:
●
Unknown signals
: select a dwell time of at least 1
second to ensure that pulses
down to a frequency of 5
Hz are weighted correctly
●
Pulsed signals or signals that fluctuate slowly
: the dwell time must cover at
least the time until the first signal peak is measured; can require long dwell time
●
unmodulated signals or signals with a high modulation frequency
: the dwell
time must cover at least the time until the first signal peak is measured; usually
shorter than for pulsed signals
Electromagnetic Interference (EMI) Measurement
