public static Signal Modulate(Signal Baseband, Signal Carrier)
{
if (Baseband.Samples.Length != Carrier.Samples.Length)
{
throw new InvalidOperationException("baseband and carrier signal must have equal number of samples");
}
return Baseband * Carrier;
}
//
//Operators
//
public static Signal operator *(Signal A, float x)
{
Signal tmp = new Signal(A.SamplingRate, A.Samples);
for (int i = 0 ; i < tmp.Samples.Length ; i++)
{
tmp.Samples[i] = tmp.Samples[i] * x;
}
return tmp;
}
/// <summary>
/// Calculates N-point frequency domain transform (Fast-Fourier Transform) of the given signal
/// </summary>
/// <param name="s">signal object</param>
/// <param name="N">value of N for N-point FFT</param>
/// <returns>Array of Complex[Re,Im] values</returns>
public static Complex[] FFT(this OpenSignalLib.Sources.Signal s, int N = 1024)
{
float[] sig = new float[s.Samples.Length];
for (int i = 0; i < s.Length; i++)
{
sig[i] = (float)s.Samples[i];
}
Complex[] fft = LiquidFFT.fft(sig, N);
return(fft);
}
public static Signal operator *(Signal A, Array x)
{
Signal tmp = new Signal(A.SamplingRate, A.Samples);
if (A.Samples.Length != x.Length)
{
throw new InvalidOperationException("Signal and Array must be of same length");
}
for (int i = 0 ; i < tmp.Samples.Length ; i++)
{
tmp.Samples[i] = tmp.Samples[i] * (double)x.GetValue(i);
}
return tmp;
}
public static Signal DeModulate(Signal PassBand, float carrier_frequency, float threshold = 0)
{
Signal ccarrier = new Sinusoidal(carrier_frequency, 0, -1, 1, PassBand.Samples.Length); // generate coherent carrier
Signal demod = ccarrier * PassBand; // multiply the carrier and the passband signal
var s = demod.Samples.Split((int)PassBand.SamplingRate);
bool[] bits = new bool[s.Count()];
int j = 0;
foreach (var item in s)
{
var sm = item.Sum();
bits[j] = sm > threshold;
j++;
}
return new BinaryData(bits, demod.Samples.Length);
}
public static Signal BFSK_DeModulate(Signal passband, float f1, float f2, float threshold = 10)
{
Sinusoidal c = new Sinusoidal(f1, 0, passband.SamplingRate, 1, passband.Samples.Length);
Signal demod = passband * c;
var s = demod.Samples.Split((int)passband.SamplingRate);
bool[] bits = new bool[s.Count()];
int j = 0;
foreach (var item in s)
{
var sm = item.Sum();
bits[j] = sm > threshold;
j++;
}
return new BinaryData(bits, demod.Samples.Length);
}
public static Signal BFSK_Modulate(BinaryData baseband, float f1, float f2)
{
Signal modFSK = new Signal();
float tmp = 1 / baseband.SamplingRate; //(30 * Math.Max(f1,f2));
float t = 0;
BaseSignalGenerator s = new BaseSignalGenerator( SignalType.Sine);
modFSK.Samples = new double[baseband.Samples.Length];
modFSK.SamplingRate = baseband.SamplingRate;
for (int i = 0 ; i < baseband.Samples.Length ; i++)
{
if (baseband.Samples[i] == 1)
{
s.Frequency = f1;
}
else
{
s.Frequency = f2;
}
modFSK.Samples[i] = s.GetValue(t);
t += tmp;
}
return modFSK;
}
public static Signal Modulate(Signal Baseband, float CarrierFrequency, float CarrierAmplitude = 1)
{
Signal Carrier = new Sinusoidal(CarrierFrequency, 0, Baseband.SamplingRate, 1, Baseband.Samples.Length);
return Baseband * Carrier;
}
public static Signal operator *(Signal A, Signal B)
{
if (A.Samples.Length != B.Samples.Length)
{
throw new InvalidOperationException("Both the operand signals must have equal number of samples");
}
if (A.SamplingRate != B.SamplingRate)
{
System.Diagnostics.Debug.Print("WARNING: Two signals with different sampling rates are being multiplied");
}
Signal temp = new Signal();
temp.Samples = new double[A.Samples.Length];
for (int i = 0 ; i < A.Samples.Length ; i++)
{
temp.Samples[i] = A.Samples[i] * B.Samples[i];
}
temp.SamplingRate = Math.Max(A.SamplingRate, B.SamplingRate);
return temp;
}
public Signal Extend(Signal sig)
{
Signal x = new Signal();
if (this.Samples == null) this.Samples = new double[0];
x.Samples = this.Samples.Concat(sig.Samples).ToArray();
if (this.SamplingRate == 0) this.SamplingRate = sig.SamplingRate;
x.SamplingRate = this.SamplingRate;
return x;
}
