Keysight Technologies N5171B EXG, Руководство пользователя

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354 Keysight EXG and MXG X-Series Signal Generators User’s Guide
Real–Time Phase Noise Impairments (Option 432)
DAC Over–Range Conditions and Scaling
DAC Over–Range Conditions and Scaling
When using phase noise impairment, it is possible to create a DAC over–range condition, which
causes the signal generator to generate an error. To minimize this condition with the phase noise
impairment feature, the Keysight X-Series signal generator incorporates an automatic DAC over–
range protection feature that scales down the I/Q data. Because it can scale the data by more than
what is actually need, it typically decreases the dynamic range of the waveform. This is especially
noticeable when using a constant amplitude signal such as GSM.
For the Dual ARB Player, the automatic over–range protection can be turned off (on is the factory
default). The control for the Dual ARB DAC over–range protection feature is located in the key path
as shown in Figure 14-3 .
Figure 14-3 Dual ARB DAC Over–Range Protection Softkey Location
In the Dual ARB Player, to avoid excessive scaling or to just perform scaling manually, turn the
over–range protection off and use the Waveform Runtime Scaling softkey to eliminate DAC over–
range conditions.
When the automatic feature is disabled, the other options to eliminate a DAC over–range condition
are to reduce the f2 value, or the Lmid value, or both until the condition corrects itself.
For details on each key, use key help
as described on
page 40
.
When the DAC over–range protection is off,
eliminate over–range conditions by
decreasing the scaling value (see
“Setting
Waveform Runtime Scaling” on
page 238
).
Default setting is On.
Turn off to manually control scaling while
using the phase noise impairment option.
Manually adjust the scaling using the
Waveform Runtime Scaling softkey
shown above.