
2-20 Programming Guide
Programming Commands and Examples ESG Family Signal Generators
:DM and :BURSt Subsystems (ESG-D and ESG-DP Series)
External ALC Bandwidth Configuration
:DM:EXternal:ALC:BWIDth|BANDwidth NORMal|NARRow
:DM:EXternal:ALC:BWIDth|BANDwidth?
This command is used to toggle between ALC normal and narrow bandwidth modes. The
choices are Normal or Narrow. You can choose to set the signal generator to narrow
bandwidth mode if you have switched on I/Q modulation, are using an external I/Q source,
and the ALC circuit is set to on. Setting the external ALC bandwidth to narrow limits the
bandwidth to 100 Hz, which can improve EVM. Narrow bandwidth mode may, however,
also slow the settling time for frequency changes as much as 40 ms. Defaults are Normal if
IQ modulation is off, Narrow if EXT IQ or HIGH BW AM is on.
*RST Value: Normal
High Crest Mode State
:DM:EXternal:HICrest[:STATe] ON|OFF|1|0
:DM:EXternal:HICrest[:STATe]?
This command is used to change operating conditions to accommodate IQ inputs with high
crest factor. Maximum output level is reduced and power level accuracy is degraded. IQ
drive levels should be reduced, dB per dB, for crest factors greater than 4 dB.
*RST Value: Off
I Channel Offset Adjustment
:DM:IQADjustment:IOFFset <val><unit>
:DM:IQADjustment:IOFFset?
This command is used to set the I channel offset, in percent of full scale. 100% offset is
equivalent to 500 mV at the input connector. Choices for the variables <val> and <unit>
range from
−100.0 to +100.0%.
When using this command to minimize the LO feedthough signal, optimum performance is
achieved when the command is sent after all other I/Q path commands are executed, such
as those that change the internal phase polarity or adjust the modulator attenuator. If
other adjustments are made after minimizing is performed, the LO feedthrough signal
may increase.
*RST Value: 0.00%
I/Q Adjustments State
:DM:IQADjustment[:STATe] ON|OFF|1|0
:DM:IQADjustment[:STATe]?
This command is used to enable the I/Q adjustments (I/Q gain, I offset, and Q offset).
The choices include On (1) or Off (0).
*RST Value: Off
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