forked from osherbakov/MELPeModem
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MILSTD188_110B_39.cs
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MILSTD188_110B_39.cs
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using System;
using System.Collections.Generic;
using System.Text;
namespace MELPeModem
{
class MILSTD188_110B_39
{
public const int BITS_PER_SYMBOL = 2;
public const float CARRIER_FREQ_LO = 675.0f;
public const float CARRIER_FREQ_HI = 2812.5f;
public const float DOPPLER_FREQ = 393.75f;
public const int NUM_FREQ = 39;
public const float SYMBOL_TIME = 0.0225f; // Every symbol lasts 22.5ms
public const float SYMBOLRATE = 1 / SYMBOL_TIME; // Symbol rate will be 44.44444444 Hz
public const int RS_BITS = 4;
public const float NORM_AMP = 1.0f / NUM_FREQ;
public const int CARRIER_LO_FFT_IDX = 12;
public const int CARRIER_HI_FFT_IDX = (CARRIER_LO_FFT_IDX + NUM_FREQ);
// Preamble parameters - for the Parts 1, 2 and 3
public const int NUMTONES1 = 4;
public const int NUMTONES2 = 3;
public const int NUMTONES3 = 39;
public const int AMPLITUDE1 = 3;
public const int AMPLITUDE2 = 4;
public const int AMPLITUDE3 = 1;
public const int AMPLITUDEDOPPLER = 2;
public const int PREAMBLE_OVERSAMPLE = 6;
public const int DOPPLERCORR_INTERVAL = 8;
public const int FREQ_OFFSET = -12;
public const float AMP_CORR1 = 1 ;/// ((NORM_AMP * AMPLITUDE1));
public const float AMP_CORR2 = 1 ;/// ((NORM_AMP * AMPLITUDE2));
public const float AMP_CORR3 = 1 ;/// ((NORM_AMP * AMPLITUDE3));
static double[] InitialPhases = {
0, 5.6, 19.7, 42.2, 73.1, 115.3, 165.9, 225.0, 295.3, 14.1,
101.3, 199.7, 303.8, 59.1, 185.6, 317.8, 101.3, 253.1, 56.3, 225.0,
45, 236.3, 73.1, 281.3, 137.8, 5.6, 239.1, 123.8, 19.7, 281.3,
194.1, 115.3, 45, 345.9, 295.3, 253.1, 222.2, 199.7, 185.6
};
static MILSTD188_110B_39()
{
modemModes = new Modes(MILSTD188_110B_39.supportedModes);
}
static float[] Baudrates = { 2400, 1200, 600, 300, 1500, 75 };
static ModeInfo[] supportedModes = {
new ModeInfo(MILSTD_188.Mode.D_2400S, 0, 0, 0, 1, 144, 56, 0, 0, 1, 78, null),
new ModeInfo(MILSTD_188.Mode.D_2400AS, 1, 0, 0, 9, 16, 56, 0, 0, 1, 78, null),
new ModeInfo(MILSTD_188.Mode.D_2400MS, 2, 0, 0, 18, 12, 56, 0, 0, 1, 78, null),
new ModeInfo(MILSTD_188.Mode.D_2400MAS, 3, 0, 0, 27, 9, 56, 0, 0, 1, 78, null),
new ModeInfo(MILSTD_188.Mode.D_2400MAL, 4, 0, 0, 36, 7, 56, 0, 0, 1, 78, null),
new ModeInfo(MILSTD_188.Mode.D_2400ML, 5, 0, 0, 72, 3, 56, 0, 0, 1, 78, null),
new ModeInfo(MILSTD_188.Mode.D_2400AL, 6, 0, 0, 144, 1, 56, 0, 0, 1, 78, null),
new ModeInfo(MILSTD_188.Mode.D_2400L, 7, 0, 0, 288, 1, 56, 0, 0, 1, 78, null),
new ModeInfo(MILSTD_188.Mode.D_1200S, 8, 1, 0, 1, 567, 28, 0, 0, 1, 64, null),
new ModeInfo(MILSTD_188.Mode.D_1200AS, 9, 1, 0, 63, 14, 28, 0, 0, 1, 64, null),
new ModeInfo(MILSTD_188.Mode.D_1200AL, 10, 1, 0, 189, 6, 28, 0, 0, 1, 64, null),
new ModeInfo(MILSTD_188.Mode.D_1200L, 11, 1, 0, 567, 1, 28, 0, 0, 1, 64, null),
new ModeInfo(MILSTD_188.Mode.D_600S, 12, 2, 0, 1, 567, 28, 0, 0, 2, 32, null),
new ModeInfo(MILSTD_188.Mode.D_600AS, 13, 2, 0, 33, 30, 28, 0, 0, 2, 32, null),
new ModeInfo(MILSTD_188.Mode.D_600AL, 14, 2, 0, 99, 10, 28, 0, 0, 2, 32, null),
new ModeInfo(MILSTD_188.Mode.D_600L, 15, 2, 0, 297, 2, 28, 0, 0, 2, 32, null),
new ModeInfo(MILSTD_188.Mode.D_300S, 16, 3, 0, 1, 567, 28, 0, 0, 4, 16, null),
new ModeInfo(MILSTD_188.Mode.D_300AS, 17, 3, 0, 17, 54, 28, 0, 0, 4, 16, null),
new ModeInfo(MILSTD_188.Mode.D_300AL, 18, 3, 0, 47, 18, 28, 0, 0, 4, 16, null),
new ModeInfo(MILSTD_188.Mode.D_300L, 19, 3, 0, 153, 4, 28, 0, 0, 4, 16, null),
new ModeInfo(MILSTD_188.Mode.D_150S, 20, 4, 0, 1, 576, 28, 0, 0, 8, 8, null),
new ModeInfo(MILSTD_188.Mode.D_150AS, 21, 4, 0, 9, 100, 28, 0, 0, 8, 8, null),
new ModeInfo(MILSTD_188.Mode.D_150AL, 22, 4, 0, 25, 36, 28, 0, 0, 8, 8, null),
new ModeInfo(MILSTD_188.Mode.D_150L, 23, 4, 0, 81, 8, 28, 0, 0, 8, 8, null),
new ModeInfo(MILSTD_188.Mode.D_75S, 24, 5, 0, 1, 567, 28, 0, 0, 16, 4, null),
new ModeInfo(MILSTD_188.Mode.D_75AS, 25, 5, 0, 4, 234, 28, 0, 0, 16, 4, null),
new ModeInfo(MILSTD_188.Mode.D_75AL, 26, 5, 0, 12, 75, 28, 0, 0, 16, 4, null),
new ModeInfo(MILSTD_188.Mode.D_75L, 27, 5, 0, 36, 16, 28, 0, 0, 16, 4, null),
};
static BitGroup[] D2400_old = { new BitGroup(0 * 78, 78) };
static BitGroup[] D1200_old = { new BitGroup(0 * 64, 64), new BitGroup(0 * 63, 14) };
static BitGroup[] D600_old = { new BitGroup(0 * 32, 32), new BitGroup(0 * 32, 32), new BitGroup(0, 14) };
static BitGroup[] D300_old = { new BitGroup(0 * 16, 16), new BitGroup(0 * 16, 16), new BitGroup(0 * 16, 16), new BitGroup(0 * 16, 16),
new BitGroup(0 * 0, 14) };
static BitGroup[] D150_old = { new BitGroup(0 * 8, 8), new BitGroup(0 * 8, 8), new BitGroup(0 * 8, 8), new BitGroup(0 * 8, 8),
new BitGroup(0 * 8, 8), new BitGroup(0 * 8, 8), new BitGroup(0 * 8, 8), new BitGroup(0 * 8, 8),
new BitGroup(0 * 0, 8), new BitGroup(0 * 8, 6) };
static BitGroup[] D75_old = { new BitGroup(0 * 0, 4), new BitGroup(0 * 4, 4), new BitGroup(0 * 4, 4), new BitGroup(0 * 4, 4),
new BitGroup(0 * 4, 4), new BitGroup(0 * 4, 4), new BitGroup(0 * 4, 4), new BitGroup(0 * 4, 4),
new BitGroup(0 * 4, 4), new BitGroup(0 * 4, 4), new BitGroup(0 * 4, 4), new BitGroup(0 * 4, 4),
new BitGroup(0 * 4, 4), new BitGroup(0 * 4, 4), new BitGroup(0 * 4, 4), new BitGroup(0 * 4, 4),
new BitGroup(0 * 4, 4), new BitGroup(0 * 4, 4), new BitGroup(0 * 4, 4), new BitGroup(0 * 4, 2) };
static BitGroup[] D2400_new = { new BitGroup(0 * 78, 78) };
static BitGroup[] D1200_new = { new BitGroup(0 * 64, 64), new BitGroup(0 * 63, 14) };
static BitGroup[] D600_new = { new BitGroup(0 * 32, 32), new BitGroup(8 * 32, 32), new BitGroup(0, 14) };
static BitGroup[] D300_new = { new BitGroup(0 * 16, 16), new BitGroup(4 * 16, 16), new BitGroup(8 * 16, 16), new BitGroup(12 * 16, 16),
new BitGroup(0 * 0, 14) };
static BitGroup[] D150_new = { new BitGroup(0 * 8, 8), new BitGroup(2 * 8, 8), new BitGroup(4 * 8, 8), new BitGroup(6 * 8, 8),
new BitGroup(8 * 8, 8), new BitGroup(10 * 8, 8), new BitGroup(12 * 8, 8), new BitGroup(14 * 8, 8),
new BitGroup(0 * 0, 8), new BitGroup(2 * 8, 6) };
static BitGroup[] D75_new = { new BitGroup(0 * 0, 4), new BitGroup(1 * 4, 4), new BitGroup(2 * 4, 4), new BitGroup(3 * 4, 4),
new BitGroup(4 * 4, 4), new BitGroup(5 * 4, 4), new BitGroup(6 * 4, 4), new BitGroup(7 * 4, 4),
new BitGroup(8 * 4, 4), new BitGroup(9 * 4, 4), new BitGroup(10 * 4, 4), new BitGroup(11 * 4, 4),
new BitGroup(12 * 4, 4), new BitGroup(13 * 4, 4), new BitGroup(14 * 4, 4), new BitGroup(15 * 4, 4),
new BitGroup(0 * 4, 4), new BitGroup(1 * 4, 4), new BitGroup(2 * 4, 4), new BitGroup(3 * 4, 2) };
static BitGroup[][] Diversity_Old = { D2400_old, D1200_old, D600_old, D300_old, D150_old, D75_old };
static BitGroup[][] Diversity_New = { D2400_new, D1200_new, D600_new, D300_new, D150_new, D75_new };
static public Modes modemModes;
public TxModem Tx;
public RxModem Rx;
public MILSTD188_110B_39(MILSTD_188.Mode modemMode, float processingFreq, float outputFreq, float[] symbolFilter, float[] outputFilter)
{
Tx = new TxModem(modemMode, processingFreq, outputFreq, symbolFilter, outputFilter);
Rx = new RxModem(outputFreq);
}
public class RxModem
{
public Preamble1Detector pd1;
public Preamble2Detector pd2;
public Preamble3Detector pd3;
public static float MaxMinRatio(float[] inputArray)
{
Array.Sort<float>(inputArray);
return (inputArray[0] != 0) ? Math.Abs(inputArray[inputArray.Length - 1] / inputArray[0]) : 0;
}
public RxModem(float samplingFreq)
{
pd1 = new Preamble1Detector(samplingFreq);
pd2 = new Preamble2Detector(samplingFreq);
pd3 = new Preamble3Detector(samplingFreq);
}
public class Preamble1Detector
{
enum STATES
{
INIT,
FIND_START1,
START1_DETECTED,
FIND_END1,
END1_DETECTED
}
float SamplingFrequency;
STATES State;
IQDetector [] ToneDetectors1; // Part 1 of the preamble
IQDetector[] ToneDetectors2; // Part 2 of the preamble
int SamplesCounter; // General purpose counter
int Counter;
float EnergyMargin = 3; // 9db of error margin
public Preamble1Detector(float samplingFreq)
{
SamplingFrequency = samplingFreq;
ToneDetectors1 = new IQDetector[NUMTONES1];
ToneDetectors2 = new IQDetector[NUMTONES2];
Init();
}
public void Init()
{
State = STATES.INIT;
ToneDetectors1[0] = new IQDetector(787.5f, SamplingFrequency, SYMBOLRATE * PREAMBLE_OVERSAMPLE, (0 * (2 * Math.PI / 360)), 0, -10, false);
ToneDetectors1[1] = new IQDetector(1462.5f, SamplingFrequency, SYMBOLRATE * PREAMBLE_OVERSAMPLE, (103.7 * (2 * Math.PI / 360)), 0, -10, false);
ToneDetectors1[2] = new IQDetector(2137.5f, SamplingFrequency, SYMBOLRATE * PREAMBLE_OVERSAMPLE, (103.7 * (2 * Math.PI / 360)), 0, -10, false);
ToneDetectors1[3] = new IQDetector(2812.5f, SamplingFrequency, SYMBOLRATE * PREAMBLE_OVERSAMPLE, (0 * (2 * Math.PI / 360)), 0, -10, false);
ToneDetectors2[0] = new IQDetector(1125.0f, SamplingFrequency, SYMBOLRATE * PREAMBLE_OVERSAMPLE, (0 * (2 * Math.PI / 360)), 0, -10, false);
ToneDetectors2[1] = new IQDetector(1800.0f, SamplingFrequency, SYMBOLRATE * PREAMBLE_OVERSAMPLE, (90.0 * (2 * Math.PI / 360)), 0, -10, false);
ToneDetectors2[2] = new IQDetector(2475.0f, SamplingFrequency, SYMBOLRATE * PREAMBLE_OVERSAMPLE, (0 * (2 * Math.PI / 360)), 0, -10, false);
Counter = 0;
}
public int SamplesProcessed { get { return Counter; } }
public bool IsSyncFound
{
get { return State == STATES.END1_DETECTED; }
}
public float FrequencyOffset
{
get
{
float FreqOffset = (ToneDetectors1[0].FrequencyOffset + ToneDetectors1[1].FrequencyOffset + ToneDetectors1[2].FrequencyOffset + ToneDetectors1[3].FrequencyOffset) / 4.0f;
return FreqOffset;
}
}
public int Process(float inSample)
{
float[] FreqEnergy1 = new float[NUMTONES1];
float TotalFreqEnergy1 = 0;
float TotalSignalEnergy = 0;
float[] FreqEnergy2 = new float[NUMTONES2];
float TotalFreqEnergy2 = 0;
bool DataReady = true;
bool ConditionsMet;
Counter++;
for (int i = 0; i < NUMTONES1; i++)
{
ToneDetectors1[i].Process(inSample);
DataReady = DataReady && ToneDetectors1[i].IsDataReady;
}
for (int i = 0; i < NUMTONES2; i++)
{
ToneDetectors2[i].Process(inSample);
DataReady = DataReady && ToneDetectors2[i].IsDataReady;
}
if (!DataReady)
return 1;
for (int i = 0; i < NUMTONES1; i++)
{
ToneDetectors1[i].GetData();
FreqEnergy1[i] = ToneDetectors1[i].FrequencyEnergy;
TotalFreqEnergy1 += FreqEnergy1[i];
}
TotalSignalEnergy = ToneDetectors1[0].SignalEnergy;
for (int i = 0; i < NUMTONES2; i++)
{
ToneDetectors2[i].GetData();
FreqEnergy2[i] = ToneDetectors2[i].FrequencyEnergy;
TotalFreqEnergy2 += FreqEnergy2[i];
}
switch (State)
{
case STATES.INIT:
State = STATES.FIND_START1;
break;
case STATES.FIND_START1:
// Process incoming signal, looking for all frequencies
// In this phase look to find NUMTONES1 frequencies
// 1. Each frequency amplitude/energy should be equal (within a margin)
// 2. Each frequency phase should be correct
// 3. Total energy should be above a certain margin
// Now check for the conditions:
// 1. Energy should be within the limit
ConditionsMet = true; // ConditionsMet = MaxMinRatio(FreqEnergy1) < EnergyMargin;
// 2. Energy of signal should be good too
ConditionsMet = ConditionsMet && ((TotalFreqEnergy1 * AMP_CORR1 * EnergyMargin ) > TotalSignalEnergy);
if (ConditionsMet)
{
State = STATES.START1_DETECTED;
SamplesCounter = 4 * PREAMBLE_OVERSAMPLE ; // Should be stable for at least 4 symbols
}
break;
case STATES.START1_DETECTED:
// The start condition was detected
// In this state we are looking for the frequency to be stable
// for at least 2 symbol periods.
// At the same time looking for Preamble 2 tones.
// The transition will happen when Preamble1 tones go below Preamble 2 tones
SamplesCounter--;
ConditionsMet = true; // MaxMinRatio(FreqEnergy1) < EnergyMargin;
// 2. Energy of signal should be good too
ConditionsMet = ConditionsMet && ((TotalFreqEnergy1 * AMP_CORR1 * EnergyMargin) > TotalSignalEnergy);
if(!ConditionsMet)
{
State = STATES.FIND_START1;
// 3. This should be for at least 3 symbols
}
else if (SamplesCounter <= 0)
{
State = STATES.FIND_END1;
}
break;
case STATES.FIND_END1:
// In this state we are looking for energy of Tones2 to become bigger than Tones 1
ConditionsMet = true; // ConditionsMet = MaxMinRatio(FreqEnergy2) < EnergyMargin;
// ConditionsMet = ConditionsMet && ((TotalFreqEnergy2 * AMP_CORR2 * EnergyMargin) > TotalSignalEnergy2);
ConditionsMet = ConditionsMet && ((TotalFreqEnergy1 * EnergyMargin) < TotalSignalEnergy);
if (ConditionsMet)
{
State = STATES.END1_DETECTED;
}
break;
default:
break;
}
return 1;
}
}
public class Preamble2Detector
{
enum STATES
{
INIT = 0,
START2_DETECTED,
END2_DETECTED,
ERROR_DETECTED
}
float SamplingFrequency;
float FreqOff;
IQDetector[] ToneDetectors;
STATES State;
int Counter; // General purpose counter
public Preamble2Detector(float samplingFreq)
{
SamplingFrequency = samplingFreq;
ToneDetectors = new IQDetector[NUMTONES2];
ToneDetectors[0] = new IQDetector(1125.0f, SamplingFrequency, SYMBOLRATE, (float)(0 * (2 * Math.PI / 360)), 0, -10, true);
ToneDetectors[1] = new IQDetector(1800.0f, SamplingFrequency, SYMBOLRATE, (float)(90 * (2 * Math.PI / 360)), 0, -10, true);
ToneDetectors[2] = new IQDetector(2475.0F, SamplingFrequency, SYMBOLRATE, (float)(0 * (2 * Math.PI / 360)), 0, -10, true);
ToneDetectors[0].StartingOffset = (int) (SamplingFrequency / (SYMBOLRATE * PREAMBLE_OVERSAMPLE));
ToneDetectors[1].StartingOffset = (int)(SamplingFrequency / (SYMBOLRATE * PREAMBLE_OVERSAMPLE));
ToneDetectors[2].StartingOffset = (int)(SamplingFrequency / (SYMBOLRATE * PREAMBLE_OVERSAMPLE));
Init(0);
}
public void Init(float frequencyOffset)
{
FreqOff = frequencyOffset;
// Here is the math:
// for (1/symbolrate) time interval the accumulated phase error was E. E = 2*pi*F * (1/sr) ==> F = (E * sr ) / (2 * pi)
foreach (IQDetector td in ToneDetectors) td.FrequencyOffset = frequencyOffset;
State = STATES.START2_DETECTED;
Counter = 0;
}
public bool IsSyncFound
{
get { return State == STATES.END2_DETECTED; }
}
public bool IsErrorFound
{
get { return State == STATES.ERROR_DETECTED; }
}
public float FrequencyOffset
{
get
{
float FreqOffset = (ToneDetectors[0].FrequencyOffset + ToneDetectors[1].FrequencyOffset + ToneDetectors[2].FrequencyOffset) / 3.0f;
return FreqOffset;
}
}
public int Process(float inSample)
{
bool FailTest;
bool DataReady = true;
for (int i = 0; i < NUMTONES2; i++)
{
ToneDetectors[i].Process(inSample);
DataReady = DataReady && ToneDetectors[i].IsDataReady;
}
if (!DataReady)
{
return 1;
}
switch (State)
{
case STATES.START2_DETECTED:
// Process incoming signal, looking for all frequencies
FailTest = false;
// All 3 detectors have data - process
// The symbols received should be alternating 0 and 1
foreach (IQDetector id in ToneDetectors)
{
if (id.GetData() != (Counter & 0x0001))
{
// FailTest = true;
}
}
Counter++;
if ((Counter >= 8) && (FailTest == false))
{
State = STATES.END2_DETECTED;
}
if (FailTest)
{
State = STATES.ERROR_DETECTED;
}
break;
default:
break;
}
return 1;
}
}
public class Preamble3Detector
{
enum STATES
{
INIT = 0,
FIRST_REF_SYMBOL,
REGULAR_DATA,
FREQ_CORRECTION
}
STATES State;
float SamplingFrequency;
IQDecoder[] OFDMDecoders;
IQDetector Doppler;
DataCombiner Despreader;
int FrameCounter;
float FreqOff;
Queue<byte> OutputData;
Queue<IQ> RawData;
int FrameSize;
OFDMFFTDemodulator FFTDemodulator;
public Preamble3Detector(float samplingFreq)
{
SamplingFrequency = samplingFreq;
Doppler = new IQDetector(DOPPLER_FREQ, SamplingFrequency, SYMBOLRATE, 0.0, 1, DOPPLERCORR_INTERVAL, false);
OFDMDecoders = new IQDecoder[NUMTONES3];
Despreader = new DataCombiner(78, D2400_new);
OutputData = new Queue<byte>();
RawData = new Queue<IQ>();
FrameSize = (int) ((SamplingFrequency / SYMBOLRATE) + 0.5);
FFTDemodulator = new OFDMFFTDemodulator(CARRIER_FREQ_LO, CARRIER_FREQ_HI, NUM_FREQ, samplingFreq, SYMBOLRATE);
for (int i = 0; i < NUMTONES3; i++)
{
OFDMDecoders[i] = new IQDecoder(BITS_PER_SYMBOL, Constellation.BitsToPhase_39, Constellation.IQTable_QPSK45,
EncodingType.DIFF_IQ);
}
Init(0);
}
public void Init(float frequencyOffset)
{
FreqOff = frequencyOffset;
FFTDemodulator.FrequencyOffset = FreqOff;
Doppler.FrequencyOffset = FreqOff;
State = STATES.FIRST_REF_SYMBOL;
FrameCounter = 0;
}
public int Process(float inSample)
{
FFTDemodulator.Process(inSample);
Doppler.Process(inSample);
if (FFTDemodulator.IsDataReady)
{
IQ Data;
int DataBits;
switch (State)
{
case STATES.FIRST_REF_SYMBOL:
IQ RotCorr;
for (int i = 0; i < NUMTONES3; i++)
{
Data = FFTDemodulator.GetData();
RotCorr = (IQ.UNITY / Data) / Data.R2;
FFTDemodulator[i].RotateCorrection = RotCorr;
OFDMDecoders[i].Init();
OFDMDecoders[i].PreviousIQ = Data * RotCorr;
OFDMDecoders[i].StartCorrectionProcess(DOPPLERCORR_INTERVAL);
}
Doppler.StartCorrectionProcess(DOPPLERCORR_INTERVAL);
State = STATES.REGULAR_DATA;
break;
case STATES.REGULAR_DATA:
for (int i = 0; i < NUMTONES3; i++)
{
Data = FFTDemodulator.GetData();
RawData.Enqueue(Data);
OFDMDecoders[i].Process(Data, out DataBits);
for (int j = 0; j < BITS_PER_SYMBOL; j++)
{
OutputData.Enqueue((byte)(DataBits & 0x0001));
DataBits >>= 1;
}
}
if (Doppler.IsCorrectionReady)
{
IQ DecodeCorr = IQ.UNITY;
for (int i = 0; i < NUMTONES3; i++)
{
// DecodeCorr += OFDMDecoders[i].FrequencyCorrection;
OFDMDecoders[i].StartCorrectionProcess(DOPPLERCORR_INTERVAL);
}
float FreqCorr = Doppler.FrequencyOffset; // +DecodeCorr;
FFTDemodulator.FrequencyOffset = FreqCorr;
Doppler.FrequencyOffset = FreqCorr;
Doppler.StartCorrectionProcess(DOPPLERCORR_INTERVAL);
}
break;
case STATES.FREQ_CORRECTION:
break;
default:
break;
}
if (FFTDemodulator.Count > 0)
{
throw new ApplicationException("Extra symbols detected");
}
FrameCounter++;
}
return 0;
}
public int Count
{
get { return OutputData.Count; }
}
public int RawCount
{
get { return RawData.Count; }
}
public byte GetData() { return OutputData.Dequeue(); }
public void GetData(byte []outputArray)
{
OutputData.CopyTo(outputArray, 0);
}
public IQ GetRawData() { return RawData.Dequeue(); }
public void GetRawData(IQ[] outputArray)
{
RawData.CopyTo(outputArray, 0);
}
}
}
public class TxModem
{
MILSTD_188.Mode ModemMode;
bool LongPreamble = false;
bool UseDopplerTone = true;
int D1, D2; // Values to inform the receiving modem aboud Rate and Interleave factor
int DataSymbols; // Number of data symbols to be sent before sync
int SyncSymbols; // Number of sync symbols to be sent
// Interleaver parameters
int InterleavingDegree;
int InterleaverNumBlocks;
int BlockLength;
int RepeatDataBits;
int BitsPerSymbol;
int BitsPerCodeword;
float DataRate; // Data transmission rate - 75-2400 bits/sec
BitGroup[] DiversityArray; // Bits diversity array
int PreambleSize;
int InputBlockSize;
Interleaver DataInterleaver;
LFSR__188_110B_39 SyncLFSR;
int LSFRSeed;
IQEncoder[] Encoder; // Each channel has a separate encoder
OFDMFFTModulator Modulator;
IQModulator PreambleModulator;
FIR OutputFilter;
Generator DopplerTone;
DataSpreader<byte> DiversitySpreader;
List<float> OutputData = new List<float>();
int[] BitsToSymbols;
int FlushModulatorLength;
int BitCounter = 0;
int OutputSymbol = 0;
int DataSymbolCounter = 0;
public TxModem(MILSTD_188.Mode modemMode, float processingFreq, float outputFreq, float[] symbolFilter, float[] outputFilter)
{
this.ModemMode = modemMode;
// Set up all the required parameters
MILSTD188_110B_39.modemModes[ModemMode].GetModeInfo(out ModemMode, out D1, out D2, out PreambleSize, out InterleavingDegree,
out InterleaverNumBlocks, out BitsPerCodeword, out SyncSymbols, out BlockLength,
out RepeatDataBits, out BitsPerSymbol, out BitsToSymbols);
this.DataRate = Baudrates[D2];
this.DiversityArray = Diversity_New[D2];
this.InputBlockSize = (int) (processingFreq / SYMBOLRATE);
// For 2400 baud we use RS(14, 10), for all others - RS(7,3)
int SymbTotal = (DataRate == 2400) ? 14 : 7;
int SymbData = (DataRate == 2400) ? 10 : 3;
DataSymbols = BitsPerCodeword * InterleavingDegree * InterleaverNumBlocks;
// DataSymbols = TotalBits * RS_BITS * InterleavingDegree * InterleaverNumBlocks; // The same
// Here is the magic formula that keeps the incoming and outgoing bitrate:
// @ 2400 K = (16 * Int * NumBlocks ) / 9
// @ any other K = (4 * Int * NumBlocks ) / 9
SyncSymbols = (((DataRate == 2400) ? 16 : 4) * InterleavingDegree * InterleaverNumBlocks) / 9;
SyncLFSR = new LFSR__188_110B_39(9, 0x0116);
// Calculate the seed value - the scrambler repeats every 2^9 - 1 = 511 symbols
// Start with the desired end value and count the (511 - necessary number of symbols)
int NumShift = 0x1FF - SyncSymbols; if (NumShift < 0) NumShift += 0x1FF;
SyncLFSR.Init(0x1FF);
SyncLFSR.Shift(NumShift + 1);
LSFRSeed = SyncLFSR.Value & 0x1FF;
this.DataInterleaver = new Interleaver_188_110B_39(InterleavingDegree, InterleaverNumBlocks, RS_BITS, SymbTotal, SymbData);
this.DataInterleaver.Init();
this.DiversitySpreader = new DataSpreader<byte>(BitsPerSymbol, this.DiversityArray);
this.DiversitySpreader.Init();
this.Encoder = new IQEncoder[NUM_FREQ];
for(int i = 0; i < NUM_FREQ; i++)
Encoder[i] = new IQEncoder(BITS_PER_SYMBOL, Constellation.BitsToPhase_39, Constellation.IQTable_QPSK45,
EncodingType.DIFF_IQ);
this.Modulator = new OFDMFFTModulator(CARRIER_FREQ_LO, CARRIER_FREQ_HI, NUM_FREQ, processingFreq, SYMBOLRATE);
this.PreambleModulator = new IQModulator(CARRIER_FREQ_LO, CARRIER_FREQ_HI, NUM_FREQ, processingFreq, SYMBOLRATE, null);
this.DopplerTone = new Generator();
this.DopplerTone.Init(DOPPLER_FREQ + FREQ_OFFSET, processingFreq, 0);
this.OutputFilter = new FIR(outputFilter, (int)(processingFreq / outputFreq));
this.FlushModulatorLength = 20;
if (symbolFilter != null) FlushModulatorLength += (symbolFilter.Length * 2);
if (outputFilter != null) FlushModulatorLength += (outputFilter.Length * 2);
}
void SendIQ(IQ iqData)
{
if (Modulator.Process(iqData * 1 * NORM_AMP) > 0)
{
float[] OutData = new float[Modulator.Count];
Modulator.GetData(OutData, 0);
if (UseDopplerTone && iqData != IQ.ZERO)
{
this.DopplerTone.GenerateAdd(2 * NORM_AMP, OutData, InputBlockSize);
}
int nSamp = OutputFilter.Decimate(OutData, 0, OutData, 0, InputBlockSize);
for (int i = 0; i < nSamp; i++) OutputData.Add(OutData[i]);
}
}
void SendBit(int bitSymb)
{
IQ IQData;
DiversitySpreader.Process((byte) bitSymb);
if (DiversitySpreader.IsDataReady)
{
byte[] OutData = new byte[DiversitySpreader.Count];
DiversitySpreader.GetData(OutData, 0);
foreach (byte OutBit in OutData)
{
// Assemble Symbol from individual bits
OutputSymbol |= (OutBit & 0x0001) << BitCounter;
BitCounter++;
if (BitCounter >= BITS_PER_SYMBOL)
{
Encoder[Modulator.Index].Process(OutputSymbol, out IQData);
SendIQ(IQData);
BitCounter = 0;
OutputSymbol = 0;
}
}
}
}
int SendBlockSync()
{
SyncLFSR.Init(LSFRSeed);
for (int i = 0; i < SyncSymbols; i++)
{
SyncLFSR.Shift();
SendBit(SyncLFSR.CurrentBit);
}
return SyncSymbols;
}
public int SendSyncPreamble(bool extendedPreamble, bool useDopplerTone)
{
int Part1Length = extendedPreamble ? 58: 14;
int Part2Length = extendedPreamble ? 27: 8;
int Part3Length = extendedPreamble ? 12: 1;
int nSamp;
IQ Symb;
int DataSize = Math.Max(Part1Length, Part2Length); DataSize = Math.Max(DataSize, Part3Length);
float[] ModDataBuff = new float[InputBlockSize * DataSize];
float[] PhasesInRads = new float[NUM_FREQ];
for (int i = 0; i < NUM_FREQ; i++) PhasesInRads[i] = (float)(InitialPhases[i] * (2 * Math.PI / 360));
//--------------------------------------------------
// Part one of the preamble
//--------------------------------------------------
PreambleModulator.Init();
PreambleModulator.FrequencyOffset = FREQ_OFFSET;
Array.Clear(ModDataBuff, 0, ModDataBuff.Length);
Symb = IQ.UNITY * AMPLITUDE1 * NORM_AMP;
for (int i = 0; i < Part1Length; i++)
{
PreambleModulator[787.5f].Process(Symb, ModDataBuff, i * InputBlockSize);
PreambleModulator[1462.5f].Process(Symb, ModDataBuff, i * InputBlockSize);
PreambleModulator[2137.5f].Process(Symb, ModDataBuff, i * InputBlockSize);
PreambleModulator[2812.5f].Process(Symb, ModDataBuff, i * InputBlockSize);
PreambleModulator.Finish(ModDataBuff, i * InputBlockSize);
}
nSamp = OutputFilter.Decimate(ModDataBuff, 0, ModDataBuff, 0, Part1Length * InputBlockSize);
for (int i = 0; i < nSamp; i++) OutputData.Add(ModDataBuff[i]);
//--------------------------------------------------
// Part two of the preamble
//--------------------------------------------------
PreambleModulator.Init();
PreambleModulator.FrequencyOffset = FREQ_OFFSET;
Array.Clear(ModDataBuff, 0, ModDataBuff.Length);
for (int i = 0; i < Part2Length; i++)
{
float Sign = (i % 2) == 0 ? 1 : -1;
Symb = IQ.UNITY * Sign * AMPLITUDE2 * NORM_AMP;
PreambleModulator[1125.0f].Process(Symb * new IQ((float)(0 * (2 * Math.PI / 360))), ModDataBuff, i * InputBlockSize);
PreambleModulator[1800.0f].Process(Symb * new IQ((float)(90 * (2 * Math.PI / 360))), ModDataBuff, i * InputBlockSize);
PreambleModulator[2475.0f].Process(Symb * new IQ((float)(0 * (2 * Math.PI / 360))), ModDataBuff, i * InputBlockSize);
PreambleModulator.Finish(ModDataBuff, i * InputBlockSize);
}
nSamp = OutputFilter.Decimate(ModDataBuff, 0, ModDataBuff, 0, Part2Length * InputBlockSize);
for (int i = 0; i < nSamp; i++) OutputData.Add(ModDataBuff[i]);
//--------------------------------------------------
// Part three of the preamble
//--------------------------------------------------
Array.Clear(ModDataBuff, 0, ModDataBuff.Length);
Symb = IQ.UNITY * AMPLITUDE3 * NORM_AMP;
for (int i = 0; i < Part3Length; i++)
{
PreambleModulator.FrequencyOffset = FREQ_OFFSET;
Array.Clear(ModDataBuff, 0, ModDataBuff.Length);
this.Modulator.Index = 0;
for (int k = 0; k < NUM_FREQ; k++)
{
IQ NewSymb = Symb * new IQ(PhasesInRads[k]);
this.Modulator[k].Process(NewSymb, ModDataBuff, i * InputBlockSize);
this.Encoder[k].PreviousIQ = NewSymb.N;
}
// this.Modulator.Finish(ModDataBuff, i * InputBlockSize);
}
if (useDopplerTone) this.DopplerTone.GenerateAdd(AMPLITUDEDOPPLER * NORM_AMP, ModDataBuff, Part3Length * InputBlockSize);
nSamp = OutputFilter.Decimate(ModDataBuff, 0, ModDataBuff, 0, Part3Length * InputBlockSize);
for (int i = 0; i < nSamp; i++) OutputData.Add(ModDataBuff[i]);
this.Modulator.Index = 0;
return OutputData.Count;
}
public bool Start()
{
SendSyncPreamble(LongPreamble, UseDopplerTone);
SendBlockSync();
return true;
}
public bool Process(byte dataBit)
{
// Fill the interleaver and start sending the data
DataInterleaver.ProcessEncode(dataBit);
if (DataInterleaver.IsDataReady)
{
byte[] OutData = new byte[DataInterleaver.Count];
DataInterleaver.GetData(OutData, 0);
foreach (byte DataBit in OutData)
{
SendBit(DataBit);
}
}
DataSymbolCounter++;
if (DataSymbolCounter >= DataSymbols)
{
SendBlockSync();
DataSymbolCounter = 0;
}
return true;
}
public bool Process(byte[] dataByteArray, int startIndex, int numDataBits)
{
// Fill the interleaver and start sending the data
while (numDataBits-- > 0)
{
Process(dataByteArray[startIndex++]);
}
return true;
}
public bool ProcessRaw(IQ[] dataArray, int startIndex, int numDataBits)
{
while (numDataBits-- > 0)
{
SendIQ(dataArray[startIndex++]);
}
return true;
}
public bool ProcessRaw(byte[] dataByteArray, int startIndex, int numDataBits)
{
IQ IQData;
// Fill the interleaver and start sending the data
while (numDataBits-- > 0)
{
// Assemble Symbol from individual bits
OutputSymbol |= (dataByteArray[startIndex++] & 0x0001) << BitCounter;
BitCounter++;
if (BitCounter >= BITS_PER_SYMBOL)
{
Encoder[Modulator.Index].Process(OutputSymbol, out IQData);
SendIQ(IQData);
BitCounter = 0;
OutputSymbol = 0;
}
}
return true;
}
public bool Finish()
{
int InterleaverFlushBits = 100;
// and send it to the Interleaver
for(int i = 0; i < InterleaverFlushBits; i++)
Process(0);
FlushInterleaver();
Modulator.Finish();
for (int j = 0; j < FlushModulatorLength * NUM_FREQ; j++)
{
SendIQ(IQ.ZERO);
}
return true;
}
void FlushInterleaver()
{
// Make sure that interleaver is completely full - fill it with zero bytes.
while (!DataInterleaver.IsDataReady)
DataInterleaver.ProcessEncode(0);
byte[] OutData = new byte[DataInterleaver.Count];
DataInterleaver.GetData(OutData, 0);
foreach (byte symb in OutData)
{
SendBit(symb);
}
}
public int GetData(float[] sampleArray)
{
int ret = OutputData.Count;
OutputData.CopyTo(sampleArray);
OutputData.Clear();
return ret;
}
public int GetData(float[] sampleArray, int startingIndex)
{
int ret = OutputData.Count;
OutputData.CopyTo(sampleArray, startingIndex);
OutputData.Clear();
return ret;
}
public int Count { get { return OutputData.Count; } }
public int SampleCount { get { return OutputData.Count; } }
public bool IsDataReady { get { return OutputData.Count > 0; } }
}
}
}