NotchFilter< T > Class Template Reference

Second-order notch (band-reject) filter (BiQuad DF2). Rejects frequencies near the center frequency and passes those further away. Useful for removing a specific unwanted frequency (e.g. mains hum at 50/60 Hz). Coefficients are derived from the Audio EQ Cookbook. More...

#include <Filter.h>

Inheritance diagram for NotchFilter< T >:

Public Member Functions
	NotchFilter ()=default
	NotchFilter (float frequency, float sampleRate, float q=1.0)
void	begin (float frequency, float sampleRate, float q=1.0)
T	process (T value) override
	Processes the input value and returns the filtered output value.
void	reset () override

Protected Attributes
T	a_1 = 0
T	a_2 = 0
T	b_0 = 0
T	b_1 = 0
T	b_2 = 0
T	w_0 = 0
T	w_1 = 0

Detailed Description

template<typename T>
class audio_tools::NotchFilter< T >

Second-order notch (band-reject) filter (BiQuad DF2). Rejects frequencies near the center frequency and passes those further away. Useful for removing a specific unwanted frequency (e.g. mains hum at 50/60 Hz). Coefficients are derived from the Audio EQ Cookbook.

Parameters

frequency	center frequency to reject in Hz
sampleRate	sample rate in Hz
q	quality factor (default 1.0; higher values narrow the rejection band)

Author

pschatzmann

Copyright

GNU General Public License v3.0

Template Parameters

T	sample type (use float or double)

Constructor & Destructor Documentation

NotchFilter() [1/2]

template<typename T >

NotchFilter ( )

default

NotchFilter() [2/2]

template<typename T >

NotchFilter ( float  frequency, float  sampleRate, float  q = 1.0  )

inline

Member Function Documentation

begin()

template<typename T >

void begin ( float  frequency, float  sampleRate, float  q = 1.0  )

inline

process()

template<typename T >

T process ( T  in )

inlineoverridevirtualinherited

Processes the input value and returns the filtered output value.

Implements Filter< T >.

reset()

template<typename T >

void reset ( )

inlineoverridevirtualinherited

Clears the internal state (delay lines) without changing the coefficients. Call after reconfiguring filter parameters via begin() to avoid transients from stale state.

Reimplemented from Filter< T >.

Member Data Documentation

a_1

template<typename T >

T a_1 = 0

protectedinherited

a_2

template<typename T >

T a_2 = 0

protectedinherited

b_0

template<typename T >

T b_0 = 0

protectedinherited

b_1

template<typename T >

T b_1 = 0

protectedinherited

b_2

template<typename T >

T b_2 = 0

protectedinherited

w_0

template<typename T >

T w_0 = 0

protectedinherited

w_1

template<typename T >

T w_1 = 0

protectedinherited

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The documentation for this class was generated from the following file:

• src/AudioTools/CoreAudio/AudioFilter/Filter.h