RFmx Demod 19.1 Help

Edition Date: October 2019

Part Number: 374641M-01

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RFmx Demod 19.1 Help
RFmx Demod 20.0 Help

int32 __stdcall RFmxDemod_Initialize (char resourceName[], char optionString[], niRFmxInstrHandle *handleOut, int32 *isNewSession);


Creates an RFmx session to the NI-RFSA supported device you specify through the resourceName parameter and returns a handleOut that identifies this device in all subsequent RFmx functions.

The RFmxDemod_Initialize function calls the RFxInstr_Initialize function.

Enabling the SFP (Soft Front Panel) debug has a performance impact. For best performance, National Instruments recommends disabling SFP debug.

  • On a 64-bit Windows, SFP debug can be enabled/disabled from either the RFmx Soft Front Panel, the RFSA Soft Front Panel, or the RFmx Debug Configuration Utility.
  • On a 32-bit Windows, SFP debug can be enabled/disabled from the RFSA Soft Front Panel or the RFmx Debug Configuration Utility.


Name Type Description
resourceName char[] Specifies the resource name of the device to initialize.

The following table shows examples of how to specify the resource name.

Example # Device Type Syntax
1 myRFmxDevice RFmx device, device name is "myRFmxDevice"
2 myLogicalName IVI logical name or virtual instrument, name is "myLogicalName"

For NI-DAQmx devices, the syntax is the device name specified in MAX, as shown in Example 1. Typical default names for NI-DAQmx devices in MAX are Dev1 or PXI1Slot2. You can rename an NI-DAQmx device by right-clicking the name in MAX, selecting Rename from the pull-down menu, and entering a new name. You can also pass the name of an IVI logical name configured with the IVI Configuration utility. For additional information about IVI, refer to the IVI section of the Measurement & Automation Explorer Help.
optionString char[] Sets the initial value of certain attributes for the session.

The following attributes are used in this parameter:

  • RFmxSetup
  • Simulate
  • AnalysisOnly

For more information about attributes used in this parameter, refer to NI RF Vector Signal Analyzers Help.

The format of this string is "AttributeName=Value", where AttributeName is the name of the attribute and Value is the value to which the attribute is set. For example, you can simulate an NI 5663E using either of the following strings:

"Simulate=1, RFmxSetup=Model:5663E"

"Simulate=1, RFmxSetup=Model:5601; Digitizer:5622; LO:5652; LOBoardType:PXIe"

To set multiple attributes, separate their assignments with a comma.

To use FPGA extensions, specify the custom LabVIEW FPGA bitfile to use with the bitfile specifier within the RFmxSetup string. For example, "RFmxSetup=bitfile:yourbitfile.lvbitx" specifies that RFmx uses yourbitfile.lvbitx as the LabVIEW FPGA bitfile for the session.

To use AnalysisOnly mode, specify the string as "AnalysisOnly=1". In this mode, user is responsible for waveform acquisition and RFmx driver will perform analysis on user specified IQ waveform or Spectrum. Use personality specific Analyze functions to perform measurements.

Note  To simulate a device using the NI 5622 (25 MHz) digitizer, set the Digitizer field to 5622_25MHz_DDC and the Simulate field to 1. You can set the Digitizer field to 5622_25MHz_DDC only when using the NI 5665.
To use an external NI Source Measure Units (SMU) as the noise source power supply for the Noise Figure (NF) measurement, use "NoiseSourcePowerSupply" as the specifier within the RFmxSetup string. For example, "RFmxSetup= NoiseSourcePowerSupply:myDCPower[0]" configures RFmx to use channel 0 on myDCPower SMU device for powering the noise source. You should allocate a dedicated SMU channel for RFmx.
Note Note  RFmx supports NI PXIe-4138 and NI PXIe-4139 SMUs.
Name Type Description
handleOut niRFmxInstrHandle* Passes a reference of the instrument session to the next function.
isNewSession int32* Returns RFMXDEMOD_VAL_TRUE if the function created a new session or RFMXDEMOD_VAL_FALSE if the function returned a reference to an existing session.

Return Value

Name Type Description
status int32 Returns the status code of this operation. The status code either indicates success or describes an error or warning condition. Examine the status code from each call to an RFmx function to determine if an error has occurred.

To obtain a text description of the status code and additional information about the error condition, call the RFmxDemod_GetError function.

The general meaning of the status code is as follows:

Value Meaning
0 Success
Positive Values Warnings
Negative Values Errors


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