单片机软件滤波办法

10种软件滤波办法的示例程序

假定从8位AD中读取数据（如果是更高位的AD可定义数据类型为int), AD采的回来给 get_ad();函数.

1、限副滤波
/* A值可根据实践情况调整
value为有用值，new_value为当时采样值
滤波程序回来有用的实践值 */
#define A 10

char value;

char filter()
{
char new_value;
new_value = get_ad();
if ( ( new_value – value > A ) || ( value – new_value > A )
return value;
return new_value;

}

2、中位值滤波法
/* N值可根据实践情况调整
排序选用冒泡法*/
#define N 11

char filter()
{
char value_buf[N];
char count,i,j,temp;
for ( count=0;count {
value_buf[count] = get_ad();
delay();
}
for (j=0;j {
for (i=0;i {
if ( value_buf[i]>value_buf[i+1] )
{
temp = value_buf[i];
value_buf[i] = value_buf[i+1];
value_buf[i+1] = temp;
}
}
}
return value_buf[(N-1)/2];
}

3、算术均匀滤波法

#define N 12

char filter()
{
int sum = 0;
for ( count=0;count {
sum + = get_ad();
delay();
}
return (char)(sum/N);
}

4、递推均匀滤波法（又称滑动均匀滤波法）
#define N 12

char value_buf[N];
char i=0;

char filter()
{
char count;
int sum=0;
value_buf[i++] = get_ad();
if ( i == N ) i = 0;
for ( count=0;count sum = value_buf[count];
return (char)(sum/N);
}

5、中位值均匀滤波法（又称防脉冲搅扰均匀滤波法）
#define N 12

char filter()
{
char count,i,j;
char value_buf[N];
int sum=0;
for (count=0;count {
value_buf[count] = get_ad();
delay();
}
for (j=0;j {
for (i=0;i {
if ( value_buf[i]>value_buf[i+1] )
{
temp = value_buf[i];
value_buf[i] = value_buf[i+1];
value_buf[i+1] = temp;
}
}
}
for(count=1;count sum += value[count];
return (char)(sum/(N-2));
}

6、限幅均匀滤波法
/*
*/
略 参阅子程序1、3

7、一阶滞后滤波法
/* 为加速程序处理速度假定基数为100，a=0~100 */

#define a 50

char value;

char filter()
{
char new_value;
new_value = get_ad();
return (100-a)*value + a*new_value;
}

8、加权递推均匀滤波法
/* coe数组为加权系数表，存在程序存储区。*/

#define N 12

char code coe[N] = {1,2,3,4,5,6,7,8,9,10,11,12};
char code sum_coe = 1+2+3+4+5+6+7+8+9+10+11+12;

char filter()
{
char count;
char value_buf[N];
int sum=0;
for (count=0,count {
value_buf[count] = get_ad();
delay();
}
for (count=0,count sum += value_buf[count]*coe[count];
return (char)(sum/sum_coe);
}

9、消抖滤波法

#define N 12

char filter()
{
char count=0;
char new_value;
new_value = get_ad();
while (value !=new_value);
{
count++;
if (count>=N) return new_value;
delay();
new_value = get_ad();
}
return value;
}

10、限幅消抖滤波法
/*
*/