Rohde & Schwarz R&S FSP Series, Operating Manual

Page: 111 / 796

Operating Manual 1164.4556.12 - 06 4.39
R&S FSP Instrument Functions
Analyzer Mode
Pressing the MAX HOLD softkey again clears the trace memory and restarts the
max hold mode.
Remote command:
DISP:WIND:TRAC:MODE MAXH
AVERAGE The AVERAGE softkey activates the trace averaging function. The average is
formed over several sweeps. Averaging can be performed with any of the detectors
available. If the detector is automatically selected by R&S FSP, the sample detector
is used.
Depending on the setting of AVG MODE, the logarithmic level values or the mea-
sured power/voltage values are averaged.
Averaging is restarted every time the AVERAGE softkey is pressed. The trace mem-
ory is always cleared.
Remote command:
DISP:WIND:TRAC:MODE AVER
Description of averaging
Averaging is carried out over the pixels derived from the measurement samples.
Several measured values may be combined in a pixel. This means that with linear
level display the average is formed over linear amplitude values and with logarithmic
level display over levels. For this reason the trace must be measured again when
changing between
LIN and LOG display mode. The settings CONT/SINGLE
SWEEP and running averaging apply to the average display analogously.
There are two methods for calculating the average. For a sweep count = 0, a run-
ning average is calculated according to the following formula:
Due to the weighting between the new measured value and the trace average, past
values 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.
If the sweep count is >1, averaging takes place over the selected number of
sweeps. In this case the displayed trace is determined during averaging according
to the following formula:
where n is the number of the current sweep (n = 2 ... SWEEP COUNT). No averag-
ing 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 single 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.
After completion of averaging, i.e. when the averaging length defined by SWEEP
COUNT is attained, a running averaging is continued with CONTINUOUS SWEEP
according to the following formula:
TRACE
9 TRACE
⋅
MeasValue +
10
-----------------------------------------------------------------
=
Trace
n
1
n
---
T
i
( )
i 1 =
n 1 –
∑
MeasValue
n
+
⋅
=