User Manual

The Spectrum Application (RF Measurements)
R&S
®
FPL1000
257User Manual 1178.3370.02 ─ 09
The detector parameters depend on the measured frequency. The time lag of the simu-
lated pointer instrument reflects the weighting factor of the signal depending on its
form, modulation, etc.
Table 7-18: Required parameters depending on frequency for RMS Average detector
Band A Band B Band C/D Band E
Frequency range <150 kHz 150 kHz to 30 MHz 30 MHz to 1 GHz >1 GHz
IF bandwidth 200 Hz 9 kHz 120 kHz 1 MHz
Time lag of simula-
ted pointer instru-
ment
160 ms 160 ms 100 ms 100 ms
Corner frequency 10 Hz 100 Hz 100 Hz 1 kHz
The same considerations apply to the dwell time as for the CISPR average detector.
Frequency Resolution - Sweep Points and Scaling
The number of sweep points defines the number of measurement values collected dur-
ing one sweep. Thus, increasing the sweep points also increases the accuracy of the
results regarding the frequency resolution.
Because EMI measurements often cover a large frequency range you should define an
adequate number of sweep points, especially when performing the measurement on a
logarithmic axis. As on a linear axis, the distance from one sweep point to the next is
calculated graphically on a logarithmic axis, and is not based on the frequency itself.
Thus, the frequency resolution between two sweep points deteriorates with higher fre-
quencies.
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. If the distance between two sweep points is larger than
RBW/3, a warning is displayed in the status bar ("Increase Sweep Points").
Measurements and Results