Commonly used digital filter functions for single chip microcomputers

#define A 10       //A value can be adjusted according to actual conditions
char value;        //value is a valid value
char filter()
{
char new_value;    //new value is the current sampling value
new value="get"_ad();
if ((new_value-value>A)‖(value-new_value>A)
return value;
return new_value;
}

///////////////////////////Median value filtering/////////////////////////

#define N 11       //N value can be adjusted according to actual situation
char filter()
{
char value_buf[N];
char count,i,j,temp;
for (count=0;count {
value_buf[count]=get_ad();   //Get sampling value
delay();
}
for (j=0;j  //The sampling values ​​are arranged from small to large, and the sorting is done by bubbling method
{
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];    //Take the middle value
}

////////////////////////////Arithmetic average filtering//////////////////////

#define N 12
char filter()
{
int sum="0";
for(count=0;count {
sum+=get_ad();
delay();
}
return (char)(sum/N);
}

/////////////////////Extremum average filtering   ///////////////////////

#define N 11       //N value can be adjusted according to actual situation
int sum="0";

char filter()
{
char value_buf[N];
char count,i,j,temp;
for (count=0;count {
value_buf[count]=get_ad();     //Get the sample value
delay();
}
for (j=0;j //The sample values ​​are arranged from small to large, and the sorting is done by bubbling method
{
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<(N-1);count++)     //Remove the first and last number
{
sum+=value_buf[count];
delay();
}
return (char)(sum/(N-2));
}

////////////////////Moving average filter (recursive average filter)////////////

#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)

}

///////////////////////Weighted average filtering//////////////////////
#define N 12
char code jq[N]={1,2,3,4,5,6,7,8,9,10,11,12};//Weighting coefficient table
char code sum_jq=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();     //Get sampling value
delay();
}
for (count=0;count sum+=value_buf[count]*jq[count];
return (char)(sum/sum_jq);
}

///////////////////////////Low-pass filter////////////////////////

#define a   0.25
char value;        //value is the existing value
char filter()
{
char new_value;    //new value is the current sampling value
new_value=get_ad();
return (a*new_value+(1-a)*value);
}