High Pass Filter

Collaboration diagram for High Pass Filter:

Data Structures
struct	a_hpf
	instance structure for High Pass Filter More...

Macros
#define	A_HPF_1(alpha)
#define	A_HPF_2(fc, ts)
#define	A_HPF_GEN(fc, ts)

Typedefs
typedef struct a_hpf	a_hpf
	instance structure for High Pass Filter

Functions
a_real	a_hpf_gen (a_real fc, a_real ts)
	generate for High Pass Filter
void	a_hpf_init (a_hpf *ctx, a_real alpha)
	initialize for High Pass Filter
a_real	a_hpf_iter (a_hpf *ctx, a_real x)
	compute for High Pass Filter
void	a_hpf_zero (a_hpf *ctx)
	zeroing for High Pass Filter

Detailed Description

Macro Definition Documentation

A_HPF_1

#define A_HPF_1

(

alpha

)

Value:

{a_real_c(alpha), 0, 0}

A_HPF_2

#define A_HPF_2	(		fc,
			ts )

Value:

{A_HPF_GEN(fc, ts), 0, 0}

A_HPF_GEN

#define A_HPF_GEN	(		fc,
			ts )

Value:

(1 / (A_REAL_TAU * a_real_c(fc) * a_real_c(ts) + 1))

Function Documentation

a_hpf_gen()

a_real a_hpf_gen	(	a_real	fc,
		a_real	ts )

generate for High Pass Filter

$$\{\begin{array}{ll}\alpha =\frac{RC}{RC+T_s},& \alpha \in [0,1]\\ RC=\frac{1}{2\pi f_c}.\end{array}$$

$$\alpha =\frac{1}{2\pi f_c{T}_s+1}$$

Parameters

[in]	fc	cut-off frequency unit(hz)
[in]	ts	sampling time unit(s)

Returns

filter coefficient [0,1]

a_hpf_init()

void a_hpf_init	(	a_hpf *	ctx,
		a_real	alpha )

initialize for High Pass Filter

Parameters

[in,out]	ctx	points to an instance of High Pass Filter
[in]	alpha	filter coefficient [0,1]

a_hpf_iter()

a_real a_hpf_iter	(	a_hpf *	ctx,
		a_real	x )

compute for High Pass Filter

$$V_{\mathrm{o}}(n)=\alpha [V_{\mathrm{o}}(n-1)+V_{\mathrm{i}}(n)-V_{\mathrm{i}}(n-1)]$$

Parameters

[in,out]	ctx	points to an instance of High Pass Filter
[in]	x	input value

Returns

output value

a_hpf_zero()

void a_hpf_zero

(

a_hpf *

ctx

)

zeroing for High Pass Filter

Parameters

[in,out]

ctx

points to an instance of High Pass Filter