Examines the input signal to calculate the peak power level and sets it as the value of the SetReferenceLevel(string, double) method. Use this method to calculate an approximate setting for the reference level.

Syntax

Namespace: NationalInstruments.RFmx.LteMX

public int AutoLevel(string selectorString, double measurementInterval, out double referenceLevel)

Remarks

The RFmxLTE Auto Level method 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 SetAutoLevelInitialReferenceLevel(string, double) method.
When using NI 5663, 5665, or 5668R devices, NI recommends that you set an appropriate value for mechanical attenuation before calling the RFmxLTE Auto Level method. Setting an appropriate value for mechanical attenuation reduces the number of times the attenuator settings are changed by this method; thus reducing wear and tear, and maximizing the life time of the attenuator.

Parameters

NameTypeDescription
selectorStringstring

Pass an empty string. The signal name that is passed when creating the signal configuration is used.

measurementIntervaldouble

Specifies the acquisition length. This value is expressed in seconds. Use this value to compute the number of samples to acquire from the signal analyzer. Auto Level method does not use any trigger for acquisition. It ignores the user-configured trigger methods. 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.

referenceLevelout double

Upon return, contains the estimated peak power level of the input signal. This value is configured in dBm for RF devices and as Vpk-pk for baseband devices. The default value of this parameter is hardware dependent.

Returns

Returns the status code of this method. The status code either indicates success or describes a warning condition.