Esempio n. 1
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        /// <summary>
        /// Performs the convolution of two real signals. The real result is returned.
        /// </summary>
        /// <remarks>Requires <paramref name="excitation"/> and <paramref name="impulse"/>
        /// to match in a length of a power of 2.</remarks>
        public static float[] Convolve(float[] excitation, float[] impulse, FFTCache cache = null)
        {
            Complex[] result = cache != null?
                               ConvolveFourier(excitation, impulse, cache) :
                                   ConvolveFourier(excitation, impulse);

            result.InPlaceIFFT();
            return(Measurements.GetRealPart(result));
        }
Esempio n. 2
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 /// <summary>
 /// Gets a linear phase convolution filter that results in this EQ when applied.
 /// </summary>
 /// <param name="eq">Source <see cref="Equalizer"/></param>
 /// <param name="sampleRate">Sample rate of the target system the convolution filter could be used on</param>
 /// <param name="length">Length of the convolution filter in samples, must be a power of 2</param>
 /// <param name="gain">Signal voltage multiplier</param>
 /// <param name="initial">Custom initial spectrum to apply the EQ on - phases will be corrected, this is not convolved,
 /// and has to be twice the size of <paramref name="length"/></param>
 public static float[] GetLinearConvolution(this Equalizer eq, int sampleRate, int length = 1024, float gain = 1,
                                            Complex[] initial = null)
 {
     Complex[] filter = new Complex[length];
     if (initial == null)
     {
         for (int i = 0; i < length; ++i)
         {
             filter[i].Real = i % 2 == 0 ? gain : -gain; // FFT of DiracDelta(x - length/2)
         }
     }
     else
     {
         for (int i = 0; i < length; ++i)
         {
             filter[i].Real = initial[i].Magnitude * (i % 2 == 0 ? gain : -gain);
         }
     }
     eq.Apply(filter, sampleRate);
     filter.InPlaceIFFT();
     return(Measurements.GetRealPart(filter));
 }