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RFmx WCDMA 19.1 Help

Edition Date: October 2019

Part Number: 375421H-01

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RFmx WCDMA 19.1 Help
RFmx WCDMA 20.0 Help

int32 __stdcall RFmxWCDMA_AutoLevel (niRFmxInstrHandle instrumentHandle, char selectorString[], float64 measurementInterval, float64* referenceLevel);


Examines the input signal to calculate the peak power level and sets it as the value of the RFMXWCDMA_ATTR_REFERENCE_LEVEL attribute. Use this function to help calculate an approximate setting for the reference level.
The RFmxWCDMA Auto Level function completes the following tasks:

  1. Resets the mixer level, mixer level offset, and IF output power offset.
  2. Sets the starting reference level to the maximum reference level supported by the device, based on the current RF attenuation, mechanical attenuation, and preamplifier enabled settings.
  3. Iterates to adjust the reference level based on the input signal peak power.
  4. Uses immediate triggering and restores the trigger settings back to user setting after the execution.

You can also specify the starting reference level using the RFMXWCDMA_ATTR_AUTO_LEVEL_INITIAL_REFERENCE_LEVEL attribute.
When using PXIe-5663, 5665, or 5668R devices, NI recommends that you set an appropriate value for mechanical attenuation before calling the RFmxWCDMA Auto Level function. Setting an appropriate value for mechanical attenuation reduces the number of times the attenuator settings are changed by this function; thus reducing wear and tear, and maximizing the life time of the attenuator.


Name Type Description
instrumentHandle niRFmxInstrHandle Specifies the instrument session. The RFmx driver obtains this parameter from the RFmxWCDMA_Initialize function.
selectorString char[] Specifies a selector string comprising of the signal name. If you do not specify the signal name, the default signal instance is used.
You can use the RFmxWCDMA_BuildSignalString function to build the selector string.
measurementInterval float64 Specifies the acquisition length. Use this value to compute the number of samples to acquire from the signal analyzer. This value is expressed in seconds.
Auto Level VI does not use any trigger for acquisition. It ignores the user-configured trigger properties. NI recommends that you set a sufficiently high measurement interval to ensure that the acquired waveform is at least as long as one period of the signal.
Name Type Description
referenceLevel float64* Returns the reference level that represents the maximum expected power of an RF input signal. This value is expressed in dBm for RF devices and Vpk-pk for baseband devices.

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 RFmxWCDMA_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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