/// <summary>
/// Negates the specified finite signal.
/// </summary>
/// <param name="s">The signal.</param>
/// <returns></returns>
public static IFiniteSignal Negate(this IFiniteSignal s)
{
return(new FiniteSignal(s.Signal.Negate().ToReadOnlyList(), s.SampleRate)
{
DisplayName = "negation result"
});
}
/// <summary>
/// Multiplies the specified finite signals.
/// </summary>
/// <param name="s1">The first signal.</param>
/// <param name="s2">The second signal.</param>
/// <returns></returns>
/// <exception cref="SamplerateMismatchException"></exception>
public static IFiniteSignal Multiply(this IFiniteSignal s1, IFiniteSignal s2)
{
if (s1.SampleRate != s2.SampleRate)
{
throw new SamplerateMismatchException();
}
int start;
IReadOnlyList <double> signal;
if (s1.Start < s2.Start)
{
start = s2.Start;
signal = s1.Signal.Skip(s2.Start - s1.Start).Multiply(s2.Signal).ToReadOnlyList();
}
else
{
start = s1.Start;
signal = s2.Signal.Skip(s1.Start - s2.Start).Multiply(s1.Signal).ToReadOnlyList();
}
return(new FiniteSignal(signal, s1.SampleRate, start)
{
DisplayName = "multiplication result"
});
}
/// <summary>
/// Convolves the specified finite signal with an infinite signal.
/// </summary>
/// <param name="s1">The finite signal.</param>
/// <param name="s2">The infinite signal.</param>
/// <returns></returns>
/// <exception cref="SamplerateMismatchException"></exception>
public static ISignal Convolve(this IFiniteSignal s1, ISignal s2)
{
if (s1.SampleRate != s2.SampleRate)
{
throw new SamplerateMismatchException();
}
return(new InfiniteSignal(
(start, length) =>
{
var l = s1.Length + Math.Max(s1.Length, length) - 1;
var n = Fft.NextPowerOfTwo(l);
var spectrum1 = Fft.RealFft(s1.Signal, n);
var signal2A = s2.GetWindowedSignal(start - s1.Length - s1.Start, s1.Length);
var spectrum2A = Fft.RealFft(signal2A, n);
var signal2B = s2.GetWindowedSignal(start - s1.Start, length);
var spectrum2B = Fft.RealFft(signal2B, n);
var spectrumA = spectrum1.Multiply(spectrum2A);
var spectrumB = spectrum1.Multiply(spectrum2B);
var signalA = Fft.RealIfft(spectrumA).Skip(s1.Length).Take(Math.Min(length, s1.Length - 1));
var signalB = Fft.RealIfft(spectrumB).Take(length);
var signal = signalA.AddFull(signalB);
return signal;
},
s1.SampleRate)
{
DisplayName = "convolution result"
});
}
/// <summary>
/// Convolves the specified finite signal with an enumerable signal.
/// </summary>
/// <param name="s1">The finite signal.</param>
/// <param name="s2">The enumerable signal.</param>
/// <returns></returns>
/// <exception cref="SamplerateMismatchException"></exception>
public static IEnumerableSignal Convolve(this IFiniteSignal s1, IEnumerableSignal s2)
{
if (s1.SampleRate != s2.SampleRate)
{
throw new SamplerateMismatchException();
}
return(new EnumerableSignal(Dsp.Convolve(s2.Signal, s1.Signal), s1.SampleRate, s1.Start + s2.Start)
{
DisplayName = "convolution result"
});
}
/// <summary>
/// Multiplies the specified finite signal with a signal.
/// </summary>
/// <param name="s1">The finite signal.</param>
/// <param name="s2">The second signal.</param>
/// <returns></returns>
/// <exception cref="SamplerateMismatchException"></exception>
public static IFiniteSignal Multiply(this IFiniteSignal s1, ISignal s2)
{
if (s1.SampleRate != s2.SampleRate)
{
throw new SamplerateMismatchException();
}
return(new FiniteSignal(s1.Signal.Multiply(s2.GetWindowedSignal(s1.Start, s1.Length)).ToReadOnlyList(), s1.SampleRate, s1.Start)
{
DisplayName = "multiplication result"
});
}
/// <summary>
/// Computes the cross-correlation of a finite and a enumerable signal.
/// </summary>
/// <param name="s1">The finite signal.</param>
/// <param name="s2">The enumerable signal.</param>
/// <returns></returns>
/// <exception cref="SamplerateMismatchException"></exception>
public static IEnumerableSignal CrossCorrelate(this IFiniteSignal s1, IEnumerableSignal s2)
{
if (s1.SampleRate != s2.SampleRate)
{
throw new SamplerateMismatchException();
}
return(new EnumerableSignal(Dsp.CrossCorrelate(s2.Signal, s1.Signal), s1.SampleRate, s1.Start - s2.Start)
{
DisplayName = "cross correlation"
});
}
/// <summary>
/// Adds the specified finite signals.
/// </summary>
/// <param name="s1">The first signal.</param>
/// <param name="s2">The second signal.</param>
/// <returns></returns>
/// <exception cref="SamplerateMismatchException"></exception>
public static IFiniteSignal Add(this IFiniteSignal s1, IFiniteSignal s2)
{
if (s1.SampleRate != s2.SampleRate)
{
throw new SamplerateMismatchException();
}
return(new FiniteSignal(
s1.Signal.AddFullWithOffset(s2.Signal, s2.Start - s1.Start).ToReadOnlyList(),
s1.SampleRate,
Math.Min(s1.Start, s2.Start))
{
DisplayName = "addition result"
});
}
/// <summary>
/// Reverses the specified finite signal.
/// </summary>
/// <param name="signal">The signal.</param>
/// <returns></returns>
public static IFiniteSignal Reverse(this IFiniteSignal signal)
{
return(new FiniteSignal(signal.Signal.Reverse().ToReadOnlyList(), signal.SampleRate, signal.Start));
}
/// <summary>
/// Multiplies the specified signal with a finite signal.
/// </summary>
/// <param name="s1">The first signal.</param>
/// <param name="s2">The finite signal.</param>
/// <returns></returns>
/// <exception cref="SamplerateMismatchException"></exception>
public static IFiniteSignal Multiply(this ISignal s1, IFiniteSignal s2)
{
return(s2.Multiply(s1));
}