public void TestConfigureLookUpTable()
{
LookUpTableConfiguration lutConfig = new LookUpTableConfiguration()
{
DutAverageInputPower_dBm = 10.0, // results in no scaling of iq data
DutInputPower_dBm = new float[] { 1.0f, 3.0f, 2.0f, 4.0f },
SupplyVoltage_V = new float[] { 5.0f, 7.0f, 6.0f, 8.0f }
};
Waveform referenceWaveform = new Waveform()
{
Data = ComplexWaveform <ComplexSingle> .FromArray1D(new ComplexSingle[] {
ComplexSingle.FromSingle(0.5f),
ComplexSingle.FromSingle(1.5f),
ComplexSingle.FromSingle(2.5f),
ComplexSingle.FromSingle(3.5f),
ComplexSingle.FromSingle(4.5f)
})
};
// p = 10log(i^2) + 10
// i = sqrt(10**(p - 10) / 10)
var writableBuffer = referenceWaveform.Data.GetWritableBuffer();
for (int i = 0; i < referenceWaveform.Data.SampleCount; i++)
{
writableBuffer[i] = ComplexSingle.FromSingle((float)Math.Sqrt(Math.Pow(10.0, (writableBuffer[i].Real - 10.0) / 10.0)));
}
Waveform envelopeWaveform = CreateLookUpTableEnvelopeWaveform(referenceWaveform, lutConfig);
ComplexSingle.DecomposeArrayPolar(envelopeWaveform.Data.GetRawData(), out float[] yi, out _);
float[] solution = new float[] { 4.5f, 5.5f, 6.5f, 7.5f, 8.5f };
using (new AssertionScope())
{
for (int i = 0; i < yi.Length; i++)
{
yi[i].Should().BeApproximately(solution[i], 0.1f);
}
}
}
/// <summary>Creates an envelope waveform utilizing the lookup table method.</summary>
/// <param name="referenceWaveform">Specifies the waveform used for RF signal generation.</param>
/// <param name="lookUpTableConfig">Specifies common settings for creating the lookup table envelope waveform.</param>
/// <returns>The lookup table envelope waveform.</returns>
public static Waveform CreateLookUpTableEnvelopeWaveform(Waveform referenceWaveform, LookUpTableConfiguration lookUpTableConfig)
{
ComplexSingle[] iq = referenceWaveform.Data.GetRawData(); // get copy of iq samples
/// power conversions needed to understand following scaling:
/// power_dBW = 20log(V) - 10log(R) - since R is 100 we get power_dBW = 20log(V) - 20
/// if we want to normalize to dbW 1ohm, we would have 20log(V) - 10log(1) = 20log(V)
/// power_dBm = power_dBW + 30 therefore power_dBm = 20log(V) + 10
/// therefore, to convert from dBm to dBW 1ohm we subtract 10 from dBm value
// scale waveform to have average dBW 1ohm power equal to dut input power normalized to dBW 1ohm
ComplexSingle scale = ComplexSingle.FromSingle((float)Math.Pow(10.0, (referenceWaveform.PAPR_dB + lookUpTableConfig.DutAverageInputPower_dBm - 10.0) / 20.0));
for (int i = 0; i < iq.Length; i++)
{
iq[i] *= scale;
}
// get 1 ohm power trace in watts of scaled iq data
float[] powerTrace_W = new float[iq.Length];
for (int i = 0; i < iq.Length; i++)
{
powerTrace_W[i] = iq[i].Real * iq[i].Real + iq[i].Imaginary * iq[i].Imaginary;
}
// get lookup table input power trace in 1ohm watts
float[] lutDutInputPowerWattOneOhm = new float[lookUpTableConfig.DutInputPower_dBm.Length];
for (int i = 0; i < lookUpTableConfig.DutInputPower_dBm.Length; i++)
{
lutDutInputPowerWattOneOhm[i] = (float)Math.Pow(10.0, (lookUpTableConfig.DutInputPower_dBm[i] - 10.0) / 10.0); // V^2 = 10^((Pin - 10.0)/10)
}
// run the trace through 1D interpolation
float[] rawEnvelope = LinearInterpolation1D(lutDutInputPowerWattOneOhm, lookUpTableConfig.SupplyVoltage_V, powerTrace_W);
// create waveform to return to the user
Waveform envelopeWaveform = CloneAndConditionReferenceWaveform(referenceWaveform);
// copy raw envelope data into cloned envelope waveform
WritableBuffer <ComplexSingle> envWfmWriteBuffer = envelopeWaveform.Data.GetWritableBuffer();
for (int i = 0; i < rawEnvelope.Length; i++)
{
envWfmWriteBuffer[i] = ComplexSingle.FromSingle(rawEnvelope[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();
}
