A. method: it is the improvement of average recursive filter method which adds the different right for the data at different time. Usually, the closer the moment of data, the bigger the right value it gets. The bigger the right value is given, sensitivity is higher, but the signal smoothness is lower.

B. advantages: for a large time delay relatively short sampling period and the time constant of the object system.

C. disadvantages: it could not rapid respond the current severity when the delay time constant is small, the sample time is long and the signal change is slow. The filter effect is worse.

D. test code

int Filter_Value; 
  
void setup () {
   Serial.begin (9600); / / initialize the serial communication 
   randomSeed (analogRead (0)); / / random seed 
} 
  
void loop () {
   Filter_Value = Filter (); / / get the filter output value 
   Serial.println (Filter_Value); / / serial output 
   delay (50); 
} 
  
/ / Used to randomly generate a current value of around 300 
int Get_AD () {
   return random (295, 305); 
} 
  
/ / Weighted average recursive filtering method 
# define FILTER_N 12 
int coe [FILTER_N] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}; / / weighting coefficient table 
int sum_coe = 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12; / / weighting factor and 
int filter_buf [FILTER_N + 1]; 
int Filter () {
   int i; 
   int filter_sum = 0; 
   filter_buf [FILTER_N] = Get_AD (); 
   for (i = 0; i <FILTER_N; i + +) {
     filter_buf [i] = filter_buf [i + 1]; / / All data left, lower still out 
     filter_sum + = filter_buf [i] * coe [i]; 
   } 
   filter_sum / = sum_coe; 
   return filter_sum; 
}