Low Pass Filter. More...

#include "math.h"

Include dependency graph for lpf.h:

Data Structures
struct	a_lpf
	instance structure for Low Pass Filter More...

Typedefs
typedef struct a_lpf	a_lpf
	instance structure for Low Pass Filter

typedef struct a_lpf	a::lpf

Functions
a_real	a_lpf_gen (a_real fc, a_real ts)
	generate for Low Pass Filter

void	a_lpf_init (a_lpf *ctx, a_real alpha)
	initialize for Low Pass Filter

a_real	a_lpf_iter (a_lpf *ctx, a_real x)
	compute for Low Pass Filter

void	a_lpf_zero (a_lpf *ctx)
	zeroing for Low Pass Filter

Detailed Description

Low Pass Filter.

low frequencies are passed, high frequencies are attenuated.

$R C \frac{d V_{o}}{dt} + V_{o} = V_{i}$

$R C \frac{V_{o} (n) - V_{o} (n - 1)}{T_{s}} + V_{o} (n) = V_{i} (n)$

$V_{o} (n) = \frac{R C}{R C + T_{s}} V_{o} (n - 1) + \frac{T_{s}}{R C + T_{s}} V_{i} (n)$

$V_{o} (n) = (1 - α) V_{o} (n - 1) + α V_{i} (n)$

$α = \frac{T_{s}}{R C + T_{s}} = \frac{T_{s}}{\frac{1}{2 π f_{c}} + T_{s}}$

Data Structures