butterworth_filter< T > Class Template Reference

#include <filters.h>

Inheritance diagram for butterworth_filter< T >:

Collaboration diagram for butterworth_filter< T >:

Public Member Functions
	butterworth_filter (int num_sample, T dt, T cutoff_frequency)
virtual	~butterworth_filter (void)
virtual void	input (T input_value)
virtual T	output (void)
virtual void	clear (void)
Public Member Functions inherited from filter< T >
	filter (void)
virtual	~filter (void)

Private Attributes
T *	mpBuffer
int	mCurIdx
int	mNumSample
T	mDt
T	mCutoffFreq
T	mValue

Detailed Description

template<typename T>
class butterworth_filter< T >

Definition at line 15 of file filters.h.

Constructor & Destructor Documentation

template<typename T >

butterworth_filter< T >::butterworth_filter	(	int	num_sample,
		T	dt,
		T	cutoff_frequency
	)

Definition at line 47 of file filters.cpp.

                                                              {
  mNumSample = num_sample;
  mDt = dt;
  mCutoffFreq = cutoff_frequency;

  mpBuffer = new T[num_sample];
  memset((void *)mpBuffer, 0, sizeof(T) * num_sample);

  mCurIdx = 0;
}

template<typename T >

butterworth_filter< T >::~butterworth_filter ( void  )

virtual

Definition at line 60 of file filters.cpp.

                                               {
  delete[] mpBuffer;
}

Member Function Documentation

template<typename T >

void butterworth_filter< T >::clear ( void  )

virtual

Implements filter< T >.

Definition at line 89 of file filters.cpp.

                                      {
  for (int i(0); i < mNumSample; ++i) {
    mpBuffer[i] = 0.0;
  }
}

template<typename T >

void butterworth_filter< T >::input ( T  input_value )

virtual

Implements filter< T >.

Definition at line 65 of file filters.cpp.

                                               {
  int j;
  T sqrt_2 = sqrt(2);
  T value = 0;
  for (j = mNumSample - 2; j >= 0; j--) {
    mpBuffer[j + 1] = mpBuffer[j];
  }

  mpBuffer[0] = input_value;
  for (j = 0; j < mNumSample; j++) {
    T t = (T)j * mDt;
    value += sqrt_2 / mCutoffFreq * mpBuffer[j] * exp(-1. / sqrt_2 * t) *
             sin(mCutoffFreq / sqrt_2 * t) * mDt;
    //    value += sqrt_2 * exp(-1./sqrt_2*t) * sin(1./sqrt_2*t ) * mDt;
  }
  mValue = value;
}

template<typename T >

T butterworth_filter< T >::output ( void  )

virtual

Implements filter< T >.

Definition at line 84 of file filters.cpp.

                                    {
  return mValue;
}

Member Data Documentation

template<typename T >

int butterworth_filter< T >::mCurIdx

private

Definition at line 25 of file filters.h.

template<typename T >

T butterworth_filter< T >::mCutoffFreq

private

Definition at line 28 of file filters.h.

template<typename T >

T butterworth_filter< T >::mDt

private

Definition at line 27 of file filters.h.

template<typename T >

int butterworth_filter< T >::mNumSample

private

Definition at line 26 of file filters.h.

template<typename T >

T* butterworth_filter< T >::mpBuffer

private

Definition at line 24 of file filters.h.

template<typename T >

T butterworth_filter< T >::mValue

private

Definition at line 29 of file filters.h.

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

• filters.h
• filters.cpp