Specifies whether the RF preamplifier is enabled in the system.

PXIe-5667, PXIe-5644/5645/5646, PXIe-5830/5831/5840/5841/5842—Automatic enables the RF preamplifier based on the value of the Reference Level property and the center frequency. Except on the PXIe-5830/5831/5832, NI-RFSA coerces this property from Automatic to the selected value.

Note For the PXIe-5840/5841, the automatically selected value may not be optimal for all measurements. At some reference levels, Enabled may improve the noise floor while Disabled may improve distortion.

PXIe-5667—Automatic is supported only when the Low Frequency Bypass Enabled property is set to Enabled. If the reference level is greater than -25 dBm, NI-RFSA disables the preamplifier. If the reference level is less than or equal to -25 dBm, NI-RFSA sets the Preamp Enabled property to Enabled when in Signal Path.

PXIe-5668 with PXIe-5698—If you set this property to Enabled, only the preamplifier on PXIe-5698 is used, and the preamplifier on PXIe-5668 remains disabled.

Default Value:

PXIe-5644/5645/5646, PXIe-5830/5831/5832/5840/5841/5842: Automatic

All other devices: Disabled

Supported Devices: PXI-5600, PXIe-5601/5603/5605/5606 (external digitizer mode), PXIe-5644/5645/5646, PXI-5661, PXIe-5663/5663E/5665/5667/5668, PXIe-5693/5698, PXIe-5830/5831/5832/5840/5841/5842

Remarks

The following table lists the characteristics of this property.

Short Name Preamp Enabled
Data type ci32.png
Permissions Read/Write
High-level VIs N/A
Channel-based No
Resettable Yes
Disabled 2500

Disables the RF preamplifier.

Enabled when in Signal Path 2501

Enables the RF preamplifier when it is in the signal path and disables it when it is not in the signal path. Only devices with an RF preamplifier on the downconverter and an RF preselector support this option. Use the RF Preamp Present property to determine whether the downconverter has a preamplifier.
Enabled 2502

Enables the RF preamplifier. If the RF preamplifier is not in a signal path, NI-RFSA returns an error. Select the Enabled when in Signal Path option whenever possible to avoid an error.
Automatic 2503

Automatically enables the RF preamplifier based on the value of the Reference Level property. This value is valid only for the PXIe-5644/5645/5646, PXIe-5667, and PXIe-5830/5831/5832/5840/5841/5842/5860.