A second order LowPass? filter. Filter design is Bilineair. Implemented using the Direct form I. Zeros with 24 bit delays but poles with 48 bit delays! Coefficients are 24 bits. Different Lookup Tables are provided with different ranges for cutoff frequency and Q(uality-factor). Filter was optimized for Q's up to 128. Higher values of Q would result in internal clipping of the recursive part of the filter. The Resonance parameter controls the Q-factor. In all the tables Q will change on a logarithmic scale.
-- ChristiaanGelauff - 30 Jan 2006