Analog Modulations
R&S
®
SMA100B
81
User Manual 1178.3834.02 ─ 03
Mode ← FM settings
Selects the mode of the frequency modulation.
"High Bandwidth"
The maximum range for modulation bandwidth is available.
"Low Noise"
Phase modulation with phase noise and spurious characteristics
close to CW mode. The range for modulation bandwidth and FM devi-
ation is reduced (see data sheet).
To reduce the phase noise further, set the
=
"Narrow"
Remote command:
PhiM
The following settings are dedicated to PhiM.
Deviation ← PhiM
Sets the phase modulation deviation in radians or degrees.
The maximal deviation depends on the RF frequency and the selected modulation
mode (see data sheet).
Maximal possible deviation is selected automatically, if one of the following applies:
●
The selected deviation is too high for the particular frequency
●
The selected frequency is outside of the range where deviation is possible.
A warning message indicates this situation, too.
Remote command:
Ratio Path2/Path1 ← PhiM
Sets the deviation ratio (path2 to path1) in per cent.
Example:
If the deviation in path1 is 10 rad and the ratio is 50%, the deviation in path 2 is auto-
matically set to 5 rad.
Remote command:
Mode ← PhiM
Selects the mode of the phase modulation.
"High Bandwidth"
The maximum range for modulation bandwidth and PhiM deviation is
available.
However, phase noise increases at low frequencies, and the range of
PhiM deviation is limited. This mode is suitable if you process high
frequencies.
Modulation Settings