RF:Power Level Type Property

NI RF Signal Generators Help (NI-RFSG 18.1)


Edition Date: June 2018
Part Number: 371025V-01
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Short Name: Power Level Type

Property of niRFSG

Specifies the way the driver interprets the value of the Power Level property. The Power Level Type property also affects how waveforms are scaled.

Supported Devices: PXIe-5644/5645/5646, PXI-5670/5671, PXIe-5672/5673/5673E, PXIe-5820/5840

Default Values:

PXIe-5820: Peak Power

All other devices: Average Power

PXI-5670/5671: While in Script mode, if the Power Level Type property is set to Average Power, the driver scales each waveform so that all waveforms have the same average power. The average power level of each waveform matches the value set in the Power Level property. You can disable this scaling operation by setting the Power Level Type property to Peak Power.

PXIe-5644/5645/5646, PXIe-5672/5673/5673E, PXIe-5820/5840: This property must be set to Peak Power when the Generation Mode property is set to Script.

Converting from Average Power to Peak Power

Typically, the Power Level Type property is set to Average Power. However, some instrument modes require this property to be set to Peak Power. Use the following equations to calculate the equivalent peak power given the desired average power for your waveform:

Where 1 is the highest possible magnitude in the waveform.

Related Topics

Spurious Performance

Optimizing for Low Power Generation

Average Power (7000)

Indicates the desired power averaged in time. The driver maximizes the dynamic range by scaling the I/Q waveform so that its peak magnitude is equal to one. If your write more than one waveform, NI-RFSG scales each waveform without preserving the power level ratio between the waveforms. This value is not valid for the PXIe-5820.

Peak Power (7001)

Indicates the maximum power level of the RF signal averaged over one period of the RF carrier frequency (the peak envelope power). This setting requires that the magnitude of the I/Q waveform must always be less than or equal to one. When using peak power, the power level of the RF signal matches the specified power level at moments when the magnitude of the I/Q waveform equals one. If you write more than one waveform, the relative scaling between waveforms is preserved. In peak power mode, waveforms are scaled according to the Software Scaling Factor property. The Peak Power Adjustment (dB) property can be used in conjunction with the Power Level property when the Power Level Type property is set to Peak Power.

Remarks

The following table lists the characteristics of this property.

Datatype iL
PermissionsRead/Write
High-level VIs niRFSG Configure Power Level Type
Channel-based No
ResettableYes

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