/// <summary>
///
/// </summary>
/// <param name="signal"></param>
/// <returns></returns>
public static IEnumerable <Complex> ToComplexNumbers(this ComplexDiscreteSignal signal)
{
for (var i = 0; i < signal.Length; i++)
{
yield return(new Complex(signal.Real[i], signal.Imag[i]));
}
}
/// <summary>
/// Superimposes signals <paramref name="signal1"/> and <paramref name="signal2"/>.
/// If sizes are different then the smaller signal is broadcast to fit the size of the larger signal.
/// </summary>
/// <param name="signal1">First signal</param>
/// <param name="signal2">Second signal</param>
public static ComplexDiscreteSignal Superimpose(this ComplexDiscreteSignal signal1, ComplexDiscreteSignal signal2)
{
Guard.AgainstInequality(signal1.SamplingRate, signal2.SamplingRate,
"Sampling rate of signal1", "sampling rate of signal2");
ComplexDiscreteSignal superimposed;
if (signal1.Length > signal2.Length)
{
superimposed = signal1.Copy();
for (var i = 0; i < signal2.Length; i++)
{
superimposed.Real[i] += signal2.Real[i];
superimposed.Imag[i] += signal2.Imag[i];
}
}
else
{
superimposed = signal2.Copy();
for (var i = 0; i < signal1.Length; i++)
{
superimposed.Real[i] += signal1.Real[i];
superimposed.Imag[i] += signal1.Imag[i];
}
}
return(superimposed);
}
/// <summary>
/// Performs the complex division of <paramref name="signal1"/> and <paramref name="signal2"/> (with normalization by length).
/// </summary>
/// <param name="signal1">First signal</param>
/// <param name="signal2">Second signal</param>
public static ComplexDiscreteSignal Divide(
this ComplexDiscreteSignal signal1, ComplexDiscreteSignal signal2)
{
Guard.AgainstInequality(signal1.SamplingRate, signal2.SamplingRate,
"Sampling rate of signal1", "sampling rate of signal2");
var length = signal1.Length;
var real = new double[length];
var imag = new double[length];
var real1 = signal1.Real;
var imag1 = signal1.Imag;
var real2 = signal2.Real;
var imag2 = signal2.Imag;
for (var i = 0; i < length; i++)
{
var den = imag1[i] * imag1[i] + imag2[i] * imag2[i];
real[i] = (real1[i] * real2[i] + imag1[i] * imag2[i]) / den;
imag[i] = (real2[i] * imag1[i] - imag2[i] * real1[i]) / den;
}
return(new ComplexDiscreteSignal(signal1.SamplingRate, real, imag));
}
/// <summary>
/// Method superimposes two signals.
/// If sizes are different then the smaller signal is broadcasted
/// to fit the size of the larger signal.
/// </summary>
/// <param name="signal1">Object signal</param>
/// <param name="signal2">Argument signal</param>
/// <returns></returns>
public static ComplexDiscreteSignal Superimpose(this ComplexDiscreteSignal signal1, ComplexDiscreteSignal signal2)
{
if (signal1.SamplingRate != signal2.SamplingRate)
{
throw new ArgumentException("Sampling rates must be the same!");
}
ComplexDiscreteSignal superimposed;
if (signal1.Length > signal2.Length)
{
superimposed = signal1.Copy();
for (var i = 0; i < signal2.Length; i++)
{
superimposed.Real[i] += signal2.Real[i];
superimposed.Imag[i] += signal2.Imag[i];
}
}
else
{
superimposed = signal2.Copy();
for (var i = 0; i < signal1.Length; i++)
{
superimposed.Real[i] += signal1.Real[i];
superimposed.Imag[i] += signal1.Imag[i];
}
}
return(superimposed);
}
/// <summary>
/// In-place signal amplification by coeff
/// </summary>
/// <param name="signal"></param>
/// <param name="coeff"></param>
public static void Amplify(this ComplexDiscreteSignal signal, double coeff)
{
for (var i = 0; i < signal.Length; i++)
{
signal.Real[i] *= coeff;
signal.Imag[i] *= coeff;
}
}
/// <summary>
/// In-place signal attenuation by coeff
/// </summary>
/// <param name="signal"></param>
/// <param name="coeff"></param>
public static void Attenuate(this ComplexDiscreteSignal signal, double coeff)
{
if (Math.Abs(coeff) < 1e-10)
{
throw new ArgumentException("Attenuation coefficient can't be zero");
}
signal.Amplify(1 / coeff);
}
/// <summary>
/// Creates the copy of <paramref name="signal"/> repeated <paramref name="n"/> times.
/// </summary>
/// <param name="signal">Signal</param>
/// <param name="n">Number of times to repeat <paramref name="signal"/></param>
public static ComplexDiscreteSignal Repeat(this ComplexDiscreteSignal signal, int n)
{
Guard.AgainstNonPositive(n, "Number of repeat times");
return(new ComplexDiscreteSignal(
signal.SamplingRate,
signal.Real.RepeatArray(n),
signal.Imag.RepeatArray(n)));
}
/// <summary>
/// Creates new signal from last <paramref name="n"/> samples of <paramref name="signal"/>.
/// </summary>
/// <param name="signal">Signal</param>
/// <param name="n">Number of samples to copy</param>
public static ComplexDiscreteSignal Last(this ComplexDiscreteSignal signal, int n)
{
Guard.AgainstNonPositive(n, "Number of samples");
Guard.AgainstExceedance(n, signal.Length, "Number of samples", "signal length");
return(new ComplexDiscreteSignal(
signal.SamplingRate,
signal.Real.FastCopyFragment(n, signal.Length - n),
signal.Imag.FastCopyFragment(n, signal.Imag.Length - n)));
}
/// <summary>
/// Concatenates <paramref name="signal1"/> and <paramref name="signal2"/>.
/// </summary>
/// <param name="signal1">First signal</param>
/// <param name="signal2">Second signal</param>
public static ComplexDiscreteSignal Concatenate(this ComplexDiscreteSignal signal1, ComplexDiscreteSignal signal2)
{
Guard.AgainstInequality(signal1.SamplingRate, signal2.SamplingRate,
"Sampling rate of signal1", "sampling rate of signal2");
return(new ComplexDiscreteSignal(
signal1.SamplingRate,
signal1.Real.MergeWithArray(signal2.Real),
signal1.Imag.MergeWithArray(signal2.Imag)));
}
/// <summary>
/// More or less efficient LINQ-less version.
/// </summary>
/// <param name="signal"></param>
/// <param name="sampleCount"></param>
/// <returns></returns>
public static ComplexDiscreteSignal Last(this ComplexDiscreteSignal signal, int sampleCount)
{
if (sampleCount <= 0 || sampleCount > signal.Length)
{
throw new ArgumentException("Number of samples must be positive and must not exceed the signal length!");
}
return(new ComplexDiscreteSignal(
signal.SamplingRate,
signal.Real.FastCopyFragment(sampleCount, signal.Length - sampleCount),
signal.Imag.FastCopyFragment(sampleCount, signal.Imag.Length - sampleCount)));
}
/// <summary>
/// Method creates new zero-padded complex discrete signal from the current signal.
/// </summary>
/// <param name="signal">Signal</param>
/// <param name="newLength">The length of a zero-padded signal.
/// By default array is zero-padded to have length of next power of 2.</param>
/// <returns>Zero padded complex discrete signal</returns>
public static ComplexDiscreteSignal ZeroPadded(this ComplexDiscreteSignal signal, int newLength)
{
if (newLength <= 0)
{
newLength = MathUtils.NextPowerOfTwo(signal.Length);
}
return(new ComplexDiscreteSignal(
signal.SamplingRate,
signal.Real.PadZeros(newLength),
signal.Imag.PadZeros(newLength)));
}
/// <summary>
/// Method returns repeated n times copy of the signal
/// </summary>
/// <param name="signal"></param>
/// <param name="times"></param>
/// <returns></returns>
public static ComplexDiscreteSignal Repeat(this ComplexDiscreteSignal signal, int times)
{
if (times <= 0)
{
throw new ArgumentException("Number of repeat times must be at least once");
}
return(new ComplexDiscreteSignal(
signal.SamplingRate,
signal.Real.RepeatArray(times),
signal.Imag.RepeatArray(times)));
}
/// <summary>
/// Method concatenates two signals.
/// </summary>
/// <param name="signal1"></param>
/// <param name="signal2"></param>
/// <returns></returns>
public static ComplexDiscreteSignal Concatenate(this ComplexDiscreteSignal signal1, ComplexDiscreteSignal signal2)
{
if (signal1.SamplingRate != signal2.SamplingRate)
{
throw new ArgumentException("Sampling rates must be the same!");
}
return(new ComplexDiscreteSignal(
signal1.SamplingRate,
signal1.Real.MergeWithArray(signal2.Real),
signal1.Imag.MergeWithArray(signal2.Imag)));
}
/// <summary>
/// Creates the delayed copy of <paramref name="signal"/>
/// by shifting it either to the right (positive <paramref name="delay"/>, e.g. Delay(1000))
/// or to the left (negative <paramref name="delay"/>, e.g. Delay(-1000)).
/// </summary>
/// <param name="signal">Signal</param>
/// <param name="delay">Delay (positive or negative number of delay samples)</param>
public static ComplexDiscreteSignal Delay(this ComplexDiscreteSignal signal, int delay)
{
var length = signal.Length;
if (delay <= 0)
{
delay = -delay;
Guard.AgainstInvalidRange(delay, length, "Delay", "signal length");
return(new ComplexDiscreteSignal(
signal.SamplingRate,
signal.Real.FastCopyFragment(length - delay, delay),
signal.Imag.FastCopyFragment(length - delay, delay)));
}
return(new ComplexDiscreteSignal(
signal.SamplingRate,
signal.Real.FastCopyFragment(length, destinationOffset: delay),
signal.Imag.FastCopyFragment(length, destinationOffset: delay)));
}
/// <summary>
/// Method performs the complex multiplication of two signals
/// (with normalization by length)
/// </summary>
/// <param name="signal1"></param>
/// <param name="signal2"></param>
/// <returns></returns>
public static ComplexDiscreteSignal Multiply(
this ComplexDiscreteSignal signal1, ComplexDiscreteSignal signal2)
{
var length = signal1.Length;
var real = new double[length];
var imag = new double[length];
var real1 = signal1.Real;
var imag1 = signal1.Imag;
var real2 = signal2.Real;
var imag2 = signal2.Imag;
for (var i = 0; i < length; i++)
{
real[i] = (real1[i] * real2[i] - imag1[i] * imag2[i]);
imag[i] = (real1[i] * imag2[i] + imag1[i] * real2[i]);
}
return(new ComplexDiscreteSignal(signal1.SamplingRate, real, imag));
}
/// Method delays the signal
/// either by shifting it to the right (positive, e.g. Delay(1000))
/// or by shifting it to the left (negative, e.g. Delay(-1000))
/// <param name="signal"></param>
/// <param name="delay"></param>
/// <returns></returns>
public static ComplexDiscreteSignal Delay(this ComplexDiscreteSignal signal, int delay)
{
var length = signal.Length;
if (delay <= 0)
{
delay = -delay;
if (delay >= length)
{
throw new ArgumentException("Delay can not exceed the length of the signal!");
}
return(new ComplexDiscreteSignal(
signal.SamplingRate,
signal.Real.FastCopyFragment(length - delay, delay),
signal.Imag.FastCopyFragment(length - delay, delay)));
}
return(new ComplexDiscreteSignal(
signal.SamplingRate,
signal.Real.FastCopyFragment(length, destinationOffset: delay),
signal.Imag.FastCopyFragment(length, destinationOffset: delay)));
}
/// <summary>
/// Attenuates <paramref name="signal"/> by <paramref name="coeff"/> in-place.
/// </summary>
/// <param name="signal">Signal</param>
/// <param name="coeff">Attenuation coefficient</param>
public static void Attenuate(this ComplexDiscreteSignal signal, double coeff)
{
Guard.AgainstNonPositive(coeff, "Attenuation coefficient");
signal.Amplify(1 / coeff);
}