Exemplo n.º 1
0
        /// <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"
            });
        }
Exemplo n.º 2
0
 /// <summary>
 ///     Gets the time domain signal.
 /// </summary>
 /// <returns></returns>
 public IReadOnlyList <double> GetTimeDomainSignal()
 {
     return(this.TimeDomainSignal ?? (this.TimeDomainSignal = Fft.RealIfft(this.Values)));
 }