SecondOrderFilterSmoothedFract32

typedef struct _ModuleSecondOrderFilterSmoothedFract32
{
    ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
    INT32 filterType;                             // Selects the type of filter that is implemented by the module: Bypass=0, Gain=1, Butter1stLPF=2, Butter2ndLPF=3, Butter1stHPF=4, Butter2ndHPF=5, Allpass1st=6, Allpass2nd=7, Shelf2ndLow=8, Shelf2ndLowQ=9, Shelf2ndHigh=10, Shelf2ndHighQ=11, PeakEQ=12, Notch=13, Bandpass=14, Bessel1stLPF=15, Bessel1stHPF=16, AsymShelf1stLow=17, AsymShelf1stHigh=18, SymShelf1stLow=19, SymShelf1stHigh=20, VariableQLPF=21, VariableQHPF=22.
    FLOAT32 freq;                                 // Cutoff frequency of the filter
    FLOAT32 gain;                                 // Amount of boost or cut to apply, in decibels (if applicable)
    FLOAT32 Q;                                    // Specifies the Q of the filter, if applicable
    FLOAT32 smoothingTime;                        // Time constant of the smoothing process
    INT32 updateActive;                           // Specifies whether the filter coefficients are updating (=1) or fixed (=0)
    fract32 smoothingCoeff;                       // Smoothing coefficient. This is computed based on the smoothingTime, sample rate, and block size of the module
    INT32 postShift;                              // Number of bits to shift
    FLOAT32 twoPowMinusPostShift;                 // 2^(-postShift). Used by to streamline the operation of the set function
    FLOAT32* coeffs;                              // coefficients
    fract32* current_coeffsFract32;               // Instantaneous coefficients in Fract32
    fract32* target_coeffsFract32;                // Desired coefficients in Fract32
    fract32* state;                               // State variables. 4 per channel.
} ModuleSecondOrderFilterSmoothedFract32Class;

 M=second_order_filter_fract32_module(NAME, ISSMOOTH)
 Creates a general purpose second order filter that implements a number
 of standard filter types.  The filter operates on multiple interleaved
 channels, with all channels being processed by the same set of 
 coefficients.  Arguments:
    NAME - name of the module.
    ISSMOOTH - indicates whether or not to use a smoothing filter
 The module has the following variables that control the design:
   filterType - integer specifying the type of the design (details below).
   freq - frequency argument (in Hz)
   Q - the sharpness or Q of the filter (dimensionless)
   gain - cut or boost, in dB.
 The argument filterType determines what design routine is run, and not
 all input arguments are used in all cases:
   0 = Pass through mode (gain = 1)
   1 = Scaler with level gain
   2 = 1st order Butterworth LPF.  [freq].
   3 = 2nd order Butterworth LPF.  [freq].
   4 = 1st order Butterworth HPF.  [freq].
   5 = 2nd order Butterworth HPF.  [freq].
   6 = 1st order Allpass. [freq].
   7 = 2nd order Allpass. [freq, Q].
   8 = 2nd order low shelf [freq, gain].
   9 = 2nd order low shelf [freq, gain, Q].
   10 = 2nd order high shelf [freq, gain].
   11 = 2nd order high shelf [freq, gain, Q].
   12 = 2nd order Peak EQ [freq, gain, Q].
   13 = 2nd order Notch [freq, Q].
   14 = 2nd order bandpass [freq, Q].
   15 = 1st order Bessel LPF [freq]
   16 = 1st order Bessel HPF [freq]
   17 = 1st order asymmetrical low shelf [freq, gain]
   18 = 1st order asymmetrical high shelf [freq, gain]
   19 = 1st order symmetrical low shelf [freq, gain]
   20 = 1st order symmetrical high shelf [freq, gain]
   21 = 2nd order variable Q Butterworth LPF [freq, Q]
   22 = 2nd order variable Q Butterworth HPF [freq, Q]