The distortion functions have slope 1 at zero, if they are differentiable at that point, at all. This ensures that signals with low amplitude are only slightly altered. Non-differentiable distortions try to have an overall slope of 1.
Odd Chebyshev polynomial
oddChebyshev n is an appropriately scaled Chebyshev polynomial of order
n must be non-negative.
Graphics.Gnuplot.Simple.plotFuncs [Graphics.Gnuplot.Simple.YRange (-1,1)] (Graphics.Gnuplot.Simple.linearScale 1000 (-7,7::Double)) (List.map oddChebyshev [0..5])