class SPCore::Saturation
Provide simple saturation methods, that limit input above the given threshold value.
Public Class Methods
gompertz(input, threshold)
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A Gompertz-sigmoid-based saturation when input is above threshold.
# File lib/spcore/util/saturation.rb, line 23 def self.gompertz input, threshold a = threshold b = -4 c = -2 x = input.abs y = 2 * a * Math::exp(b * Math::exp(c * x)) if input > 0.0 return y else return -y end end
sigmoid(input, threshold)
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Sigmoid-based saturation when input is above threshold. From musicdsp.org, posted by Bram.
# File lib/spcore/util/saturation.rb, line 6 def self.sigmoid input, threshold input_abs = input.abs if input_abs < threshold return input else #y = threshold + (1.0 - threshold) * mock_sigmoid((input_abs - threshold) / ((1.0 - threshold) * 1.5)) y = threshold + (1.0 - threshold) * Math::tanh((input_abs - threshold)/(1-threshold)) if input > 0.0 return y else return -y end end end