Files
foc/3rd/lowpass_filter.c
2025-11-12 10:32:45 +08:00

43 lines
739 B
C

#include <stdint.h>
float y = 0;
float Lowpassfilter_sim(float x)
{
float out = 0.9*x + 0.1*y;
y = x;
return out;
}
uint32_t Last_Timesamp = 0.0;
float Last_y = 0.0;
float Lowpassfilter(float Tf, float x)
{
float dt = 0.0;
//TODO
uint32_t Timesamp = 0;
//uint32_t Timestamp = SysTick->VAL;
if(Timesamp < Last_Timesamp) dt = (float)(Last_Timesamp - Timesamp)/9*1e-6;
else
dt = (float)(0xFFFFFF - Timesamp + Last_Timesamp)/9*1e-6;
if(dt<0.0||dt==0) dt = 0.0015f;
else if(dt>0.005f)
{
Last_y = x;
Last_Timesamp = Timesamp;
return x;
}
float alpha = Tf / (Tf + dt);
float y = alpha * Last_y + (1.0f - alpha) * x;
Last_y = y;
Last_Timesamp = Timesamp;
return y;
}