character
chebyshev ripple db (<0.0)
qfactor (resonator) (>0.0)
frequency Alpha Low Alpha Up or

samplerate: Hz
Lower corner Hz Midi note (69=A440)
Upper corner Hz Midi note (69=A440)
more matched z-transform (better off, check frequency response)
prewarp (better on)
output
Signal bits (including sign): -1 bit saturation save
brutal shift, this will remove shifts up to 4 positions by changing the factor, hence reducing accuracy by maximum 4 bits but more efficient calculation
execution

//Band pass proportional-integral filter order=1 alpha1=0.1 class filter { public: filter() { v[0]=0; v[1]=0; } private: short v[2]; public: short step(short x) { v[0] = v[1]; long tmp = (((x * 32768L) //= ( 1.0000000000e+0 * x) + (v[0] * 32768L) //+( 1.0000000000*v[0]) )+16384) >> 15; // round and downshift fixed point /32768 v[1]= (short)tmp; return (short)(( (v[1] - v[0]))); // 2^ } };