void FftSpectrum(WWDecimalComplex[] signalTime)
{
WWDecimalFft fft = new WWDecimalFft(LENGTH);
var signalFreq = fft.ForwardFft(signalTime, 1M / LENGTH);
var result = new Dictionary <double, double>();
Parallel.For(0, LENGTH / 2, i => {
decimal magnitude = signalFreq[i].Magnitude();
double db = (double)(20M * WWDecimalMath.Log10(magnitude));
lock (result) {
result.Add((double)(SAMPLERATE * i / LENGTH), db);
}
});
foreach (var item in result)
{
Console.WriteLine("{0},{1}", item.Key, item.Value);
}
}
public static void TestLog10()
{
for (int i = 1; i < 10; ++i)
{
Console.WriteLine("log10({0})={1}", i, WWDecimalMath.Log10(i));
}
Console.WriteLine("log10({0})={1}", 10M, WWDecimalMath.Log10(10M));
Console.WriteLine("log10({0})={1}", 1.0M, WWDecimalMath.Log10(1.0M));
Console.WriteLine("log10({0})={1}", 1.0e-1M, WWDecimalMath.Log10(1.0e-1M));
Console.WriteLine("log10({0})={1}", 1.0e-2M, WWDecimalMath.Log10(1.0e-2M));
Console.WriteLine("log10({0})={1}", 1.0e-3M, WWDecimalMath.Log10(1.0e-3M));
Console.WriteLine("log10({0})={1}", 1.0e-4M, WWDecimalMath.Log10(1.0e-4M));
Console.WriteLine("log10({0})={1}", 1.0e-5M, WWDecimalMath.Log10(1.0e-5M));
Console.WriteLine("log10({0})={1}", 1.0e-6M, WWDecimalMath.Log10(1.0e-6M));
Console.WriteLine("log10({0})={1}", 1.0e-7M, WWDecimalMath.Log10(1.0e-7M));
Console.WriteLine("log10({0})={1}", 1.0e-8M, WWDecimalMath.Log10(1.0e-8M));
Console.WriteLine("log10({0})={1}", 1.0e-9M, WWDecimalMath.Log10(1.0e-9M));
Console.WriteLine("log10({0})={1}", 1.0e-10M, WWDecimalMath.Log10(1.0e-10M));
Console.WriteLine("log10({0})={1}", 1.0e-11M, WWDecimalMath.Log10(1.0e-11M));
Console.WriteLine("log10({0})={1}", 1.0e-12M, WWDecimalMath.Log10(1.0e-12M));
Console.WriteLine("log10({0})={1}", 1.0e-13M, WWDecimalMath.Log10(1.0e-13M));
Console.WriteLine("log10({0})={1}", 1.0e-14M, WWDecimalMath.Log10(1.0e-14M));
Console.WriteLine("log10({0})={1}", 1.0e-15M, WWDecimalMath.Log10(1.0e-15M));
Console.WriteLine("log10({0})={1}", 1.0e-16M, WWDecimalMath.Log10(1.0e-16M));
Console.WriteLine("log10({0})={1}", 1.0e-17M, WWDecimalMath.Log10(1.0e-17M));
Console.WriteLine("log10({0})={1}", 1.0e-18M, WWDecimalMath.Log10(1.0e-18M));
Console.WriteLine("log10({0})={1}", 1.0e-19M, WWDecimalMath.Log10(1.0e-19M));
Console.WriteLine("log10({0})={1}", 1.0e-20M, WWDecimalMath.Log10(1.0e-20M));
Console.WriteLine("log10({0})={1}", 1.0e-21M, WWDecimalMath.Log10(1.0e-21M));
Console.WriteLine("log10({0})={1}", 1.0e-22M, WWDecimalMath.Log10(1.0e-22M));
Console.WriteLine("log10({0})={1}", 1.0e-23M, WWDecimalMath.Log10(1.0e-23M));
Console.WriteLine("log10({0})={1}", 1.0e-24M, WWDecimalMath.Log10(1.0e-24M));
Console.WriteLine("log10({0})={1}", 1.0e-25M, WWDecimalMath.Log10(1.0e-25M));
Console.WriteLine("log10({0})={1}", 1.0e-26M, WWDecimalMath.Log10(1.0e-26M));
Console.WriteLine("log10({0})={1}", 1.0e-27M, WWDecimalMath.Log10(1.0e-27M));
}