Instructions

Chapter 2 Front Panel Operations RIGOL
DSG800 User Guide 2-29
I/Q Modulation (Only Available for
DSG821A/DSG836A)
I/Q modulation can improve the spectrum utilization. In I/Q modulation, two
orthogonal signals (carriers with the same frequency and 90°phase deviation,
generally expressed as Sin and Cos) are modulated with the I (In-Phase components)
and Q (Quadrature Phase components) signals respectively and then they are
transmitted together.
Press MOD  I/Q Mod to enter the I/Q modulation parameter setting menu.
To Turn on I/Q Modulation
Press Switch to select "On" or "Off".
 On: turn on the I/Q modulation function. The IQ label in the function status area
in the user interface is illuminated.
 Off: turn off the I/Q modulation function and this is the default state.
Note: The amplitude modulation function and I/Q modulation function cannot be
turned on at the same time. If a sweep manner is selected and the step sweep time
is lower than 50 ms, "You can turn on the IQ Modulation when sweep time is greater
than 50ms" will be displayed in the user interface when I/Q modulation is turned on.
To Select the Modulation Source
Press Source to select "Int" or "Ext" modulation source.
1. Internal Source
When "Int" is selected, the built-in baseband generator (wavetable) of the
instrument provides the modulating signal. At this point, if I/Q modulation is
already turned on, the baseband output will be turned "On" automatically. The
RF signal generator will output the I (In-Phase) components and Q (Quadrature
Phase) components of the I/Q modulation baseband signal from the [I OUT]
and [Q OUT] connectors (as shown in the figures below) at the rear panel
respectively.