R&S FSV-K7, Operating Manual, Page: 62 / 262

Analog Demodulation Option R&S FSV–K7
R&S
®
FSV-K7/K7S
62 Operating Manual 1176.7561.02 ─ 06
Logarithmic averaging is recommended to display signals with a low signal to noise
ratio. While positive 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 FSVA/FSV 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 both logarithmic and linear averaging has the
same results.
Lin ← Average Mode
Activates linear averaging. 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.
This softkey takes effect if the grid is set to a linear scale (see "Range Linear" softkey,
"Range Linear %" on page 45). In this case, 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, dBµV, dBµA or dBpW: the data is converted
into V prior to averaging, i.e. averaging is done in V.
Remote command:
SENS:AVER1:TYPE LIN
, see
[SENSe:]AVERage<n>:TYPE
on page 158
Log ← Average Mode
Activates logarithmic averaging.
This averaging method only takes effect if the grid is set to a logarithmic scale
("Range" softkey), i.e. the unit of the data is dBm. In this case the values are averaged
in dBm. Otherwise (i.e. with linear scaling), the behavior is the same as with linear
averaging (see
Lin softkey). For further information on logarithmic scaling refer to the
"Average Mode" softkey.
Remote command:
SENS:AVER1:TYPE VID
, see
[SENSe:]AVERage<n>:TYPE
on page 158
Power ← Average Mode
Activates linear power averaging.
The power level values are converted into unit Watt prior to averaging. After the aver-
aging, the data is converted back into its original unit.
Unlike the linear mode, the averaging is always done in W.
Remote command:
SENS:AVER1:TYPE POW
, see
[SENSe:]AVERage<n>:TYPE
on page 158
Softkeys of the Analog Demodulation option