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124 Chapter 4
Basic Digital Operation
Local Settings for ARB Waveform Formats and the Dual ARB Player
SCPI Command Changes
New SCPI commands have been developed and included in the C.03.10 and later versions of the firmware.
These new commands allow you to set the three parameters discussed earlier for each of the ARB
modulation formats and the dual ARB player. Commands have also been changed for the three parameters in
the Digital Modulation subsystem to accommodate the local setting feature.
These new commands duplicate the behavior of the softkeys discussed in the previous section. The main
difference is that now you can set new values for the three parameters (available in the I/Q and/or MUX
menus) while an ARB modulation format is active and playing. However, the new settings will not be
applied until the ARB format is turned off. Then they are used only if a real-time modulation format is
turned on or an external I/Q signal is applied to the ESG.
The pre-C.03.10 Digital Modulation subsystem filter and attenuator commands will still work and have the
same behavior, in that they apply changes globally. This means that if you configure a local setting for an
ARB format using the new commands, and then executed the older commands from the Digital Modulation
subsystem, the older commands would override the local settings.
Waveform Runtime Scaling
Waveform runtime scaling enables you to set the scaling value that is applied to the waveform while it is
playing.
You can set waveform runtime scaling in the
ARB Setup
softkey menu located in the dual ARB player. The
location of this softkey is shown in Figure 4-14 . This setting is only available for the dual ARB player.
When you save the signal generator setup using the front panel
Save
hardkey function with the dual ARB
player, the local setting for waveform runtime scaling is also saved.
High Crest Mode
High crest mode reduces ALC levels while processing ARB waveform files, resulting in signals with less
distortion and improved EVM. However, in the high crest mode, the maximum output level is reduced and
power level accuracy is degraded.
You can set this parameter by in the
ARB Setup
softkey menu located in the dual ARB player. The location of
this softkey is shown in Figure 4-14 . This setting is only available in the dual ARB player.
When you save the signal generator setup using the front panel
Save
hardkey function with the dual ARB
player, the local setting for high crest mode is also saved.
ARB Sample Clock
Each ARB modulation format and the dual ARB player incorporate a local ARB sample clock parameter.
For example, you can set the ARB CDMA2000 modulation format’s ARB sample rate to 5 MHz, and this
parameter would apply only to the ARB CDMA2000 waveform that is currently playing. The 5 MHz setting