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Short Name: Offset Units
Property of niRFSG
Supported Devices: PXIe-5644/5645/5646, PXIe-5673/5673E, PXIe-5820/5840
Default Value: Percent
The AWG or VST offset is the specified percentage of the AWG or VST peak power level when the Offset Units property is set to Percent. Given perfect carrier leakage suppression, the following equation is satisfied:
If the I Offset property is set to 100%, the Q Offset property is set to 0%, and the Power Level (dBm) property is set to 0 dBm, the desired RF signal is at 0 dBm and the carrier leakage is also at 0 dBm.
The AWG or VST peak power level changes when settings change in other properties such as the Power Level (dBm), Frequency (Hz), IQ Skew (Degrees), Gain Imbalance (dB), Attenuator Hold Enabled, and Arb Pre-filter Gain (dB) properties. When the Offset Units property is set to Percent, the actual AWG or VST offset changes as the AWG or VST peak power level changes in order to satisfy the preceding equations. These changes are useful if you are intentionally adding carrier leakage to test the tolerance of a receiver. When the Offset Units property is set to Percent, the carrier leakage, in dBc, remains at a consistent level.
If you are trying to eliminate residual carrier leakage due to calibration inaccuracies or drift, set the Offset Units property to volts. Offset correction voltage is applied to the I/Q modulator or VST, regardless of changes to the AWG or VST peak power level.
Specifies the I Offset and Q Offset property units as percent.
Specifies the I Offset and Q Offset property units as volts.
The following table lists the characteristics of this property.