Operating Manual EMI TEST RECEIVER ESIB7 - Rohde & Schwarz

Traces - Analyzer
ESIB
BLANK
AVERAGE
The BLANK softkey activates the blanking of the trace.
However, the trace remains stored in memory and can be displayed again by
pressing VIEW. The markers for the blanked trace are also erased. After
reactivation of the trace (with VIEW, CLEAR / WRITE, MAX HOLD, MIN
HOLD, AVERAGE) the markers will be restored their their previous positions.
IEC/IEEE-bus command
:DISPlay[:WINDow]:TRACe OFF
The AVERAGE softkey activates the trace averaging function. The average is
formed over several sweeps. The average can be calculated for each
available detector. If the detector is automatically selected by the ESIB , the
sampling detector is used.
After enabling the averaging mode, the first trace is recorded in
CLEAR/WRITE mode with the selected detector. After the second sweep, the
average is then formed for each succeeding sweep. Here, the average is
formed over the samples/pixels, i.e., according to the LIN or LOG setting,
over amplitudes or levels.
Averaging is restarted every time the AVERAGE softkey is pressed. The
trace memory is also cleared. This is also the case when the trace is
switched from the setting AVERAGE to VIEW or BLANK
IEC/IEEE-bus command
:DISPlay[:WINDow]:TRACe:MODE AVER
Description of averaging:
Averaging is carried out using the pixels which are derived from the measurement value samples.
These pixels may in some cases be comprised of several combined measurement values. This means
that the average is formed over linear amplitude values when the level display is linear and over levels
when the level display is logarithmic. Because of this, the trace must be measured anew when changing
between the LIN and LOG display mode. The settings CONT/SINGLE SWEEP and the sliding average
apply to the average display analogously.
Two calculation procedures are available for averaging. For SWEEP COUNT= 0 , a sliding average is
calculated using the following equation:
9*TRACEn
TRACEn
=
+ Meas_Value
10
- 1
Because of the relative weighting of the new measurement value and the trace average, past values
have practically no no influence on the displayed trace after about 10 sweeps. For this setting, the signal
noise is effectively reduced without the need to restart the averaging process even if the signal is
changed.
If the SWEEP COUNT is >1 averaging takes place over the selected number of sweeps. In this case,
the displayed trace is given by the following formula during averaging::
TRACE
n
⎡n
1
= ⎢∑ − n ⎢⎣
i=
1
1
( Ti)
⎤
+ Meas Value⎥
⎥⎦
where n is the number of the current sweep (n = 2 ... SWEEP COUNT). For the first sweep, an average
is not calculated. The measurement values are stored directly in trace memory. With growing n, the
displayed trace becomes increasingly smoother since more individual trace data are available for
averaging.
The average is stored in trace memory after the defined number of sweeps. Until this number of sweeps
is reached, a preliminary average is displayed.
1088.7531.12 4.228 E-15