R&S FSL Setting Traces – TRACE Key
1300.2519.12 4.49 E-11
Logarithmic averaging is preferred to display signals with a low signal to noise ratio. While
p
ositive peak values are decreased in logarithmic averaging due to the characteristics involved,
it is also true that negative peaks are increased relative to the average value.If the distorted
amplitude distribution is averaged, a value is obtained that is smaller than the actual average
value. The difference is -2.5 dB.
This low average value is usually corrected in noise power measurements by a 2.5 dB factor.
Therefore the R&S FSL offers the selection of linear averaging. The trace data is converted to
linear values prior to averaging, then averaged and reconverted to logarithmic values. After
these conversions the data is displayed on the screen. The average value is always correctly
displayed irrespective of the signal characteristic.
In case of stationary sinusoidal signals all averaging methods have the same results.
LOG
Activates logarithmic averaging.
This averaging method only takes effect if the grid is set to a logarithmic scale (see Range Log
softkey). In this case the values are averaged in dBm. Otherwise (i.e. with linear scaling) the
behaviour is the same as with linear averaging (see LIN softkey). For further information on
logarithmic scaling refer to the Average Mode softkey.
This softkey is available from firmware version 1.90.
Remote: CALC:MATH:MODE LOG
LIN
Activates linear voltage or power averaging, depending on the selected unit.
Linear averaging means that the power level values are converted into linear units prior to
averaging. After the averaging, the data is converted back into its original unit.
The averaging is done in two ways (depending on the set unit – see Unit softkey):
– The unit is set to either W or dBm: the data is converted into W prior to averaging, i.e.
averaging is done in W.
– The unit is set to either V, A, dBmV, dBM V, dBMA or dBpW: the data is converted into V prior to
averaging, i.e. averaging is done in V.
This softkey is available from firmware version 1.90.
Remote: CALC:MATH:MODE LIN
To Next Page
Loading...
