public void TestWhiteGaussianNoiseIsWhite()
{
for (int z = 0; z < 10; z++) // run test 10 times to be sure
{
IChannelSource source = new WhiteGaussianNoiseSource();
double[] signal = new double[signalLength];
double signalPower = 0d;
for (int i = 0; i < signal.Length; i++)
{
signal[i] = source.ReadNextSample();
signalPower += signal[i] * signal[i];
}
signalPower /= signalLength;
Assert.Less(signalPower, 1.1, "signal power must be less than 1.1");
Assert.Greater(signalPower, 0.9, "signal power must be greater than 0.9");
double[] freqReal, freqImag;
RealFourierTransformation fft = new RealFourierTransformation();
fft.TransformForward(signal, out freqReal, out freqImag);
double spectralPower = 0d;
double[] spectralGroupPower = new double[groupCount];
for (int i = 0, j = 0; i < spectralGroupPower.Length; i++, j += groupLength)
{
double sum = 0d;
for (int k = 0; k < groupLength; k++)
{
double real = freqReal[j + k];
double imag = freqImag[j + k];
sum += real * real + imag * imag;
}
spectralGroupPower[i] = sum / (2 * groupLength);
spectralPower += sum;
Assert.Less(spectralGroupPower[i], 1.4, "spectral power must be less than 1.4 for each group");
Assert.Greater(spectralGroupPower[i], 0.6, "spectral power must be greater than 0.6 for each group");
}
spectralPower /= (2 * signalLength);
Assert.AreEqual(signalPower, spectralPower, 0.0001, "Signal and spectral power must match.");
}
}
public void TestWhiteGaussianNoiseIsWhite()
{
for (int z = 0; z < 10; z++) // run test 10 times to be sure
{
IChannelSource source = new WhiteGaussianNoiseSource();
Complex[] signal = new Complex[SignalLength];
double signalPower = 0d;
for (int i = 0; i < signal.Length; i++)
{
signal[i] = source.ReadNextSample();
signalPower += Math.Pow(signal[i].Magnitude, 2.0);
}
signalPower /= SignalLength;
Assert.Less(signalPower, 1.1, "signal power must be less than 1.1");
Assert.Greater(signalPower, 0.9, "signal power must be greater than 0.9");
Fourier.Forward(signal);
double spectralPower = 0d;
double[] spectralGroupPower = new double[GroupCount];
for (int i = 0, j = 0; i < spectralGroupPower.Length; i++, j += GroupLength)
{
double sum = 0d;
for (int k = 0; k < GroupLength; k++)
{
sum += Math.Pow(signal[j + k].Magnitude, 2.0);
}
spectralGroupPower[i] = sum / GroupLength;
spectralPower += sum;
Assert.Less(spectralGroupPower[i], 1.4, "spectral power must be less than 1.4 for each group");
Assert.Greater(spectralGroupPower[i], 0.6, "spectral power must be greater than 0.6 for each group");
}
spectralPower /= SignalLength;
Assert.AreEqual(signalPower, spectralPower, 0.0001, "Signal and spectral power must match.");
}
}
