The Spectrum Application (RF Measurements)
R&S
®
FPL1000
464
User Manual 1178.3370.02 ─ 03
10
*
9
MeasValue
Trace
Trace
old
Figure 7-48: Equation 1
Due to the weighting between the current trace and the average trace, past val-
ues have practically no influence on the displayed trace after about ten
sweeps. With this setting, signal noise is effectively reduced without need for
restarting the averaging process after a change of the signal.
–
In
"Single"
sweep mode, the current trace is averaged with the previously
stored averaged trace. No averaging is carried out for the first sweep but the
measured value is stored in the trace memory. The next time a sweep is per-
formed, the trace average is calculated according to the following formula:
2
MeasValue
Trace
Trace
old
The averaged trace is then stored in the trace memory.
●
sweep count = 1
The currently measured trace is displayed and stored in the trace memory. No
averaging is performed.
●
sweep count > 1
For both
"Single"
sweep mode and
"Continuous"
sweep mode, averaging takes
place over the selected number of sweeps. In this case the displayed trace is
determined during averaging according to the following formula:
1
1
)
(
1
n
i
n
i
n
MeasValue
T
n
Trace
Figure 7-49: Equation 2
Where n is the number of the current sweep (n = 2 ... Sweep Count).
No averaging is carried out for the first sweep but the measured value is stored in
the trace memory. With increasing n, the displayed trace is increasingly smoothed
since there are more individual sweeps for averaging.
After the selected number of sweeps, the average trace is saved in the trace mem-
ory. Until this number of sweeps is reached, a preliminary average is displayed.
When the averaging length defined by the "Sweep Count" is attained, averaging is
continued in continuous sweep mode or for "Continue Single Sweep" according to
the following formula:
N
MeasValue
Trace
N
Trace
old
*
)
1
(
Where N is the sweep count
How Trace Data is Averaged - the Averaging Mode
When the trace is averaged over several sweeps (Trace mode: "Average" ), different
methods are available to determine the trace average.
Trace Configuration
