RIGOL DSG3000 Series - Manual (Page 60)

RIGOL Chapter 2 Front Panel Operations
2-20 DSG3000 User’s Guide
To Set the Modulation Depth
The modulation depth indicates the extent of output amplitude variation and is
expressed as a percentage. The range of AM modulation depth is from 0% to 100%.
Press AM  Depth to set the AM modulation depth.
1. Select “Int” modulation source
AM modulation depth (
a
m
) and the amplitude difference (
sb
ΔP ) between the
carrier and sidebands satisfy the following relation:
a sb
m
ΔP
lg 20 6
− =
 When modulation depth is 0%, the instrument outputs a single frequency
carrier signal.
 The greater the modulation depth is, the smaller the difference between the
output amplitude and carrier amplitude and the better the symmetry of the
output amplitudes of the upper and lower sidebands.
2. Select “Ext” modulation source
 To achieve a modulation depth of 100%, the external modulation source
must input a signal (-1V to +1V).
 If the external modulation source inputs a signal (-500mV to +500mV), the
measured modulation depth is 50%.
3. Select “Int & Ext” modulation source
If modulation depth is set to 50%, the modulation depth of the internal
modulation source and that of the external modulation source each is 25%
respectively. These parameters meet the relationship: the modulation depth
setting = the internal modulation depth + the external modulation depth, and
the modulation depth of the internal modulation source equals that of the
external modulation source.
To Select the Modulation Waveform
Press AM  Source to select “Int” or “Int & Ext” modulation source; press
Waveform to select “Sine” or “Square” and the default is “Sine”.
NOTE: When “Ext” modulation source is selected, this menu is grayed out and
disabled.