Cascade of biquadratic sections

Typedefs
typedef struct SDTBiquad	SDTBiquad
	Opaque data structure for biquad cascade object.
typedef struct SDTBiquad	SDTBiquad
	Opaque data structure for biquad cascade object.

Functions
SDTBiquad *	SDTBiquad_new (int nSections)
	Object constructor. More...
void	SDTBiquad_free (SDTBiquad *x)
	Object destructor. More...
void	SDTBiquad_butterworthLP (SDTBiquad *x, double fc)
	Designs a Butterworth lowpass filter, at the given cutoff frequency. More...
void	SDTBiquad_butterworthHP (SDTBiquad *x, double fc)
	Designs a Butterworth highpass filter, at the given cutoff frequency. More...
void	SDTBiquad_butterworthAP (SDTBiquad *x, double fc)
void	SDTBiquad_linkwitzRileyLP (SDTBiquad *x, double fc)
	Designs the lowpass part of a Linkwitz-Riley crossover filter, at the given cutoff frequency. WARNING: the filter must have an even number of biquad sections! More...
void	SDTBiquad_linkwitzRileyHP (SDTBiquad *x, double fc)
	Designs the highpass part of a Linkwitz-Riley crossover filter, at the given cutoff frequency. WARNING: the filter must have an even number of biquad sections! More...
double	SDTBiquad_dsp (SDTBiquad *x, double in)
	Signal processing routine. Call this function at sample rate to compute the filtered signal. More...

Detailed Description

Classic cascade of biquad sections, useful to implement a wide variety of filters.

Function Documentation

void SDTBiquad_butterworthHP	(	SDTBiquad *	x,
		double	fc
	)

Designs a Butterworth highpass filter, at the given cutoff frequency.

Parameters

[in]

fc

Cutoff frequency, in Hz

void SDTBiquad_butterworthLP	(	SDTBiquad *	x,
		double	fc
	)

Designs a Butterworth lowpass filter, at the given cutoff frequency.

Parameters

[in]

fc

Cutoff frequency, in Hz

double SDTBiquad_dsp	(	SDTBiquad *	x,
		double	in
	)

Signal processing routine. Call this function at sample rate to compute the filtered signal.

Parameters

[in]

in

Input sample

Returns

Output sample

void SDTBiquad_free

(

SDTBiquad *

x

)

Object destructor.

Parameters

[in]

x

Pointer to the instance to destroy

void SDTBiquad_linkwitzRileyHP	(	SDTBiquad *	x,
		double	fc
	)

Designs the highpass part of a Linkwitz-Riley crossover filter, at the given cutoff frequency. WARNING: the filter must have an even number of biquad sections!

Parameters

[in]

fc

Cutoff frequency, in Hz

void SDTBiquad_linkwitzRileyLP	(	SDTBiquad *	x,
		double	fc
	)

Designs the lowpass part of a Linkwitz-Riley crossover filter, at the given cutoff frequency. WARNING: the filter must have an even number of biquad sections!

Parameters

[in]

fc

Cutoff frequency, in Hz

SDTBiquad * SDTBiquad_new

(

int

nSections

)

Object constructor.

Parameters

[in]

nSections

Number of sections in the cascade. The order of the resulting filter is twice this value (i.e. nSections = 4 -> order = 8).

Returns

Pointer to the new instance