心率识别程序求解释

`unsigned char rhythmcount(unsigned char *fifo)

`unsigned char rhythmcount(unsigned char *fifo)
{
      signed char i;
      signed char diff[max_data];          //求导数数据区
      signed char dif_max=0;                //导数最大值
      signed char thr_max;                   //阈值最大值
      unsigned char j=0;
      signed char k[8];                      //最大值数组
      unsigned char rhythm;
      float DR_R;                            //R-R间距

      *diff=0;                               //数据区首两个数据导数置0
      *(diff+1)=0;
      for(i=2;i
      {
            *(diff+i)=(signed char)(*(fifo+i+1))+2*(signed char)(*(fifo+i+2))-(signed char)(*(fifo+i-1))-2*(signed char)(*(fifo+i-2));
      }
      *(diff+max_data-1)=0;                //数据区末两个数据导数置0
      *(diff+max_data)=0;
      for(i=0;i
      {
            if((dif_max)>*(diff+i))
            dif_max=*(diff+i);
      }
      thr_max=(dif_max>>1)-(dif_max>>3);    //设定阈值，为导数最大值的0.375倍
      for(i=1;ithr_max和f(i)*f(i+1)<0这两个条件的值找到,即为R波最高点
      {
            if((*(diff+i)>thr_max)&&(((*(diff+i))^(*(diff+i+1)))>>7))
            k[j++]=i;
      }
      DR_R=(k[j-1]-k[0])/(j-1);             //计算R-R间距
      rhythm=(unsigned char)(12000/DR_R);    //通过公式200*60/DR-R求得心率值
      return rhythm;
}`