/// <summary>Creates an envelope waveform utilizing the detrough method.</summary>
/// <param name="referenceWaveform">Specifies the waveform used for RF signal generation.</param>
/// <param name="detroughConfig">Specifies common settings for creating the detrough envelope waveform.</param>
/// <returns>The detrough envelope waveform.</returns>
public static Waveform CreateDetroughEnvelopeWaveform(Waveform referenceWaveform, DetroughConfiguration detroughConfig)
{
Waveform envelopeWaveform = CloneAndConditionReferenceWaveform(referenceWaveform);
WritableBuffer <ComplexSingle> envWfmWriteBuffer = envelopeWaveform.Data.GetWritableBuffer();
double[] envelope = envelopeWaveform.Data.GetMagnitudeDataArray(false);
double detroughRatio = detroughConfig.MinimumVoltage_V / detroughConfig.MaximumVoltage_V;
// Waveforms are assumed to be normalized in range [0, 1], so no normalization will happen here
switch (detroughConfig.Type)
{
case DetroughType.Exponential:
// Formula: e = IQmag + d*exp(-IQmag/d)
for (int i = 0; i < envWfmWriteBuffer.Size; i++)
{
envelope[i] = envelope[i] + detroughRatio * Math.Exp(-envelope[i] / detroughRatio);
}
break;
case DetroughType.Cosine:
// Formula: e = 1 - (1-d)*cos(IQmag*pi/2)
for (int i = 0; i < envWfmWriteBuffer.Size; i++)
{
envelope[i] = 1.0 - (1.0 - detroughRatio) * Math.Cos(envelope[i] * Math.PI / 2.0);
}
break;
case DetroughType.Power:
// Formula: e = d + IQmag^(exponent)*(1-d)
for (int i = 0; i < envWfmWriteBuffer.Size; i++)
{
envelope[i] = detroughRatio + Math.Pow(envelope[i], detroughConfig.Exponent) * (1 - detroughRatio);
}
break;
default:
throw new ArgumentException("Detrough type not supported.\n");
}
double max = envelope.Max();
for (int i = 0; i < envelope.Length; i++)
{
envelope[i] *= detroughConfig.MaximumVoltage_V / max;
envWfmWriteBuffer[i] = ComplexSingle.FromSingle((float)envelope[i]);
}
return(envelopeWaveform);
}
/// <summary>
/// This example illustrates how to use RFSG drivers and envelope tracking APIs to configure envelope tracking.
/// </summary>
static void Main(string[] args)
{
#region Example Settings
// Select mode for use in the example
EnvelopeMode mode = EnvelopeMode.Detrough;
string waveformPath = @"C:\Users\Public\Documents\National Instruments\RFIC Test Software\Waveforms\LTE_FDD_DL_1x20MHz_TM11_OS4.tdms";
#endregion
#region Configure RF Generator
// Initialize instrument sessions
NIRfsg rfVsg = new NIRfsg("5840", true, false);
// Load up waveform
Waveform rfWfm = LoadWaveformFromTDMS(waveformPath);
// Configure RF generator
InstrumentConfiguration rfInstrConfig = InstrumentConfiguration.GetDefault();
ConfigureInstrument(rfVsg, rfInstrConfig);
DownloadWaveform(rfVsg, rfWfm);
ConfigureContinuousGeneration(rfVsg, rfWfm);
#endregion
#region Configure Tracker Generator
NIRfsg envVsg = new NIRfsg("5820", true, false);
// Configure envelope generator
EnvelopeGeneratorConfiguration envInstrConfig = EnvelopeGeneratorConfiguration.GetDefault();
TrackerConfiguration trackerConfig = TrackerConfiguration.GetDefault();
ConfigureEnvelopeGenerator(envVsg, envInstrConfig, trackerConfig);
Waveform envWfm = new Waveform();
switch (mode)
{
case EnvelopeMode.Detrough:
// Create envelope waveform
DetroughConfiguration detroughConfig = DetroughConfiguration.GetDefault();
detroughConfig.MinimumVoltage_V = 1.5;
detroughConfig.MaximumVoltage_V = 3.5;
detroughConfig.Exponent = 1.2;
detroughConfig.Type = DetroughType.Exponential;
envWfm = CreateDetroughEnvelopeWaveform(rfWfm, detroughConfig);
break;
case EnvelopeMode.LUT:
LookUpTableConfiguration lutConfig = new LookUpTableConfiguration
{
DutAverageInputPower_dBm = rfInstrConfig.DutAverageInputPower_dBm
};
// Todo - initialize lookup table
envWfm = CreateLookUpTableEnvelopeWaveform(rfWfm, lutConfig);
break;
}
ScaleAndDownloadEnvelopeWaveform(envVsg, envWfm, trackerConfig);
ConfigureContinuousGeneration(envVsg, envWfm, "PFI0");
#endregion
// Start envelope tracking
SynchronizationConfiguration syncConfig = SynchronizationConfiguration.GetDefault();
InitiateSynchronousGeneration(rfVsg, envVsg, syncConfig);
// Wait until user presses a button to stop
Console.WriteLine("Press any key to abort envelope tracking..");
Console.ReadKey();
AbortGeneration(envVsg);
AbortGeneration(rfVsg);
// Close instruments
rfVsg.Close();
envVsg.Close();
}
