public QAM(int amplitudes, int phases, int frequencies, int frameLength)
{
m_NumFrequencies = frequencies;
m_NumAmplitudes = amplitudes;
m_NumPhases = phases;
m_FrameLength = frameLength;
m_FFT = new FFT(frameLength);
}
private void paintControl1_Paint(object sender, PaintEventArgs e)
{
Graphics g = e.Graphics;
g.Clear(Color.Black);
int frameLength = 64;
int numFreqs = (int)numericUpDown4.Value;
int numAmps = (int)Math.Pow(2.0f, (float)numericUpDown1.Value);
int numPhases = (int)Math.Pow(2.0f, (float)numericUpDown2.Value);
Constellation constellation = comboBox1.SelectedIndex == 0 ? (Constellation)new CircularConstellation(numAmps, numPhases) : (Constellation)new RectangularConstellation(numAmps, numPhases);
SymbolStream symbolStream = new SymbolStream(constellation.NumSymbols);
QAM modulator = new QAM(constellation, numFreqs, frameLength);
string inString = "Hello World!";
byte[] inBytes = Encoding.ASCII.GetBytes(inString);
List<uint> inSymbols = symbolStream.EncodeSymbols(inBytes);
List<float> stream = new List<float>();
int symbolIndex = 0;
m_NumFrames = 0;
while (symbolIndex < inSymbols.Count)
{
int symbolCount = Math.Min(inSymbols.Count - symbolIndex, numFreqs);
List<uint> subSymbols = inSymbols.GetRange(symbolIndex, symbolCount);
subSymbols.Add(0);
float[] fragment = modulator.Modulate(subSymbols);
stream.AddRange(fragment);
symbolIndex += symbolCount;
m_NumFrames++;
}
float noiseScale = (float)numericUpDown3.Value / 20.0f;
float[] noise = Noise.GenerateNoise(stream.Count, (float)numericUpDown3.Value / 20.0f);
List<float> noisyStream = new List<float>();
int shifter = (int)(Math.Round((m_Random.NextDouble() * 2.0f - 1.0f) * (float)numericUpDown5.Value));
for (int i = 0; i < stream.Count; i++)
{
noisyStream.Add(noise[i] + stream[Math.Max(0, Math.Min(stream.Count - 1, i + shifter))]);
}
List<uint> outSymbols = new List<uint>();
for (int i = 0; i < noisyStream.Count; i += frameLength)
{
float[] fragment = noisyStream.GetRange(i, frameLength).ToArray();
List<uint> subSymbols = modulator.Demodulate(fragment);
outSymbols.AddRange(subSymbols);
}
byte[] outBytes = symbolStream.DecodeSymbols(outSymbols);
string outString = Encoding.ASCII.GetString(outBytes);
float curY = 100.0f;
float streamScale = 840.0f / stream.Count;
float streamSize = frameLength * streamScale;
float symbolsPerByte = m_NumFrames / (float)inBytes.Length;
for (int i = 0; i < inString.Length; i++)
{
float symbol = (float)i * symbolsPerByte;
g.DrawString(inString[i].ToString(), m_Font, Brushes.White, new PointF(20.0f + symbol * streamSize, curY));
}
curY += 16.0f;
for (int f = 0; f < m_NumFrames; f++)
{
int symbolStart = f * numFreqs;
int symbolEnd = Math.Min(inSymbols.Count - 1, symbolStart + numFreqs);
float frameStart = streamSize * f;
float Y = 0.0f;
float X = 0.0f;
for (int i = symbolStart; i < symbolEnd; i++)
{
string str = inSymbols[i].ToString();
SizeF strSize = g.MeasureString(str, m_Font);
if (X >= streamSize - 10.0f)
{
X = 0.0f;
Y += strSize.Height + 2;
}
g.DrawString(str, m_Font, Brushes.White, new PointF(20.0f + frameStart + X, curY + Y));
X += strSize.Width;
}
}
int graphMax = 0;
curY += 26.0f;
m_SourceY = curY;
m_SourceX = 20.0f;
m_SourceWidth = streamScale * (float)stream.Count;
int useFrame = Math.Min(m_NumFrames - 1, m_ActiveFrame);
DrawGraph(g, 20, curY, stream.ToArray(), streamScale, 32.0f, Pens.Aqua, Pens.SteelBlue, frameLength, useFrame, out graphMax);
m_SourceHeight = graphMax + 10.0f;
curY += graphMax + 10.0f;
DrawGraph(g, 20, curY, noise, streamScale, 32.0f, Pens.Red, Pens.Red, 1, -1, out graphMax);
curY += 32.0f * noiseScale * 1.5f + 10.0f;
DrawGraph(g, 20, curY, noisyStream.ToArray(), streamScale, 32.0f, Pens.Yellow, Pens.LightYellow, frameLength, -1, out graphMax);
curY += graphMax + 10.0f;
for (int f = 0; f < m_NumFrames; f++)
{
int symbolStart = f * numFreqs;
int symbolEnd = Math.Min(inSymbols.Count - 1, symbolStart + numFreqs);
float frameStart = streamSize * f;
float Y = 0.0f;
float X = 0.0f;
for (int i = symbolStart; i < symbolEnd; i++)
{
string str = outSymbols[i].ToString();
SizeF strSize = g.MeasureString(str, m_Font);
if (X >= streamSize - 10.0f)
{
X = 0.0f;
Y += strSize.Height + 2;
}
Brush useBrush = outSymbols[i] != inSymbols[i] ? Brushes.Red : new SolidBrush(Color.FromArgb(0, 255, 0));
g.DrawString(str, m_Font, useBrush, new PointF(20.0f + frameStart + X, curY + Y));
X += strSize.Width;
}
}
curY += 16.0f;
for (int i = 0; i < inString.Length; i++)
{
float symbol = (float)i * symbolsPerByte;
Brush useBrush = outString[i] != inString[i] ? Brushes.Red : new SolidBrush(Color.FromArgb(0, 255, 0));
g.DrawString(outString[i].ToString(), m_Font, useBrush, new PointF(20.0f + symbol * streamSize, curY));
}
curY += 16.0f;
g.DrawString("amps", m_Font, Brushes.Yellow, new PointF(5, 25));
g.DrawString("phases", m_Font, Brushes.Yellow, new PointF(65, 25));
g.DrawString("freqs", m_Font, Brushes.Yellow, new PointF(125, 25));
g.DrawString("noise", m_Font, Brushes.Yellow, new PointF(205, 25));
g.DrawString(String.Format("QAM-{0} x{1}, {2} bits per frame, {3} message len", modulator.NumSymbols, modulator.NumFrequencies, Math.Log(Math.Pow(modulator.NumSymbols, modulator.NumFrequencies), 2), m_NumFrames), m_Font, Brushes.Yellow, new PointF(310, 25));
float markerSize = constellation.NumSymbols > 64 ? 6 : 12;
DrawConstellation(g, constellation, 200, 550, 150.0f, markerSize);
{
int symbolStart = useFrame * numFreqs;
int symbolEnd = Math.Min(inSymbols.Count - 1, symbolStart + numFreqs);
FFT fft = new FFT(frameLength);
float[] data = noisyStream.GetRange(useFrame * frameLength, frameLength).ToArray();
float nrm = (float)numFreqs;
List<FFT.Complex> coeffs = fft.DFT(data, nrm).ToList();
coeffs = coeffs.OrderBy(x => -x.Magnitude).ToList();
coeffs = coeffs.GetRange(0, numFreqs);
coeffs = coeffs.OrderBy(x => x.freq).ToList();
float magNrm = 2.0f / (float)frameLength;
List<uint> correctSymbols = inSymbols.GetRange(symbolStart, symbolEnd - symbolStart);
for (int f = 0; f < correctSymbols.Count; f++)
{
uint subSymbol = (uint)constellation.FindSymbol(coeffs[f].Magnitude * magNrm, coeffs[f].Angle);
float x = (float)Math.Cos(coeffs[f].Angle) * coeffs[f].Magnitude * magNrm * 150.0f;
float y = (float)Math.Sin(coeffs[f].Angle) * coeffs[f].Magnitude * magNrm * 150.0f;
x += 200.0f;
y += 550.0f;
Pen usePen = subSymbol != correctSymbols[f] ? Pens.Red : new Pen(Color.FromArgb(0, 255, 0));
g.DrawLine(usePen, x - markerSize * 0.5f, y, x + markerSize * 0.5f, y);
g.DrawLine(usePen, x, y - markerSize * 0.5f, x, y + markerSize * 0.5f);
}
}
}
public QAM(Constellation constellation, int frequencies, int frameLength)
{
m_Constellation = constellation;
m_NumFrequencies = frequencies;
m_FrameLength = frameLength;
m_FFT = new FFT(frameLength);
}
