User manual

Chapter 2 Front Panel Operations RIGOL
DSG800 User's Guide 2-15
To Set the Modulation Depth
The modulation depth denotes the extent of output amplitude variation and is
expressed as a percentage. The range of AM modulation depth is from 0% to 100%.
Press Depth to set the AM modulation depth.
1. When "Int" modulation source is selected
The AM modulation depth (
a
m
) and the amplitude difference (
sb
ΔP
) between
the carrier and sidebands satisfy the following relation.
asb
mΔP lg206 −=
 When the modulation depth is 0%, the instrument outputs a carrier signal
with a single frequency point.
 The greater the modulation depth is, the smaller the difference between the
output amplitude and carrier amplitude will be.
2. When "Ext" modulation source is selected
 100% modulation depth refers to the modulation depth corresponding to 1
Vpp input amplitude of the external modulation source.
 When the input amplitude of the external modulation source is 0.5 Vpp, the
modulation depth actually measured is 50%.
To Select the Modulation Waveform
Press Source to select "Int" 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.
To Set the Modulation Frequency
Press Source to select "Int" modulation source; press Freq to set the modulation
frequency.
 Use the numeric keyboard or knob to input the desired frequency value.
 For sine waveforms, the range of the modulation frequency is from 10 Hz to 100
kHz.
 For square waveforms, the range of the modulation frequency is from 10 Hz to
20 kHz.
Note: When "Ext" modulation source is selected, this menu is grayed out and
disabled.