EEPW论坛

（1）高通与低通系数

#if LOWPASS
float32 B [FILTER_LEN] = {0.0625L, 0.25L, 0.375L, 0.25L, 0.0625L};     
#elif HIGHPASS
float32 B [FILTER_LEN] = {0.0625L, -0.25L, 0.375L, -0.25L, 0.0625L}; 
#endif

（2）算法实现

       FILTER_LEN = 5

       变量定义：

       float32   fir[FILTER_LEN];
       float32   fir_temp,Y,Y_OUT;

       FIR计算：

       fir[0] = AdcResult.ADCRESULT1;     //取ADC值
       fir_temp = fir[4];                                
       Y = B[4] * fir_temp;                           //系数乘法计算
       
       fir[4] = fir[3];                                     //移位
       fir_temp = fir[3];
       Y = Y + B[3] * fir_temp;                    //累加
       
       fir[3] = fir[2];
       fir_temp = fir[2];
       Y = Y + B[2] * fir_temp;
       
       fir[2] = fir[1];
       fir_temp = fir[1];
       Y = Y + B[1] * fir_temp;
       
       fir[1] = fir[0];
       fir_temp = fir[0];
       Y = Y + B[0] * fir_temp;
       
       Y_OUT = Y;                  //FIR输出