APP_Framework/Framework/: complete one order RC low pass filter.

APP_Framework/Framework/knowing/filter/low_pass_filter/one_order_rc_lpf.c

@@ -1 +1,22 @@
-#include<one_order_rc_lpf.h>
+#include<one_order_rc_lpf.h>
+void OneOrderRcLpfInit(OneOrderRcLpfHander* hander,float cutoff_fre,float sampling)
+{
+    hander->vi = 0;
+    hander->fcutoff = cutoff_fre;   // low pass filter cutoff frequency
+    hander->vo = 0;
+    hander->vo_prev = 0;
+    hander->fs = sampling;          //sampling rate
+}
+
+float OneOrderRcLpfFun(OneOrderRcLpfHander *hander)
+{
+    float rc;
+    float alpha1;
+    float alpha2;
+    rc = (float) 1.0/2.0/3.1415926/hander->fcutoff;
+    alpha1 = 1/(1+rc*hander->fs);
+    alpha2 = rc*hander->fs/(1+rc*hander->fs);
+    hander->vo = alpha1*hander->vi + alpha2 *hander->vo_prev;
+    hander->vo_prev = hander ->vo;
+    return hander->vo;
+}

APP_Framework/Framework/knowing/filter/low_pass_filter/one_order_rc_lpf.h

@@ -2,4 +2,15 @@
 #define _ONE_ORDER_RC_LPF_H
 
 
+typedef struct 
+{
+	float  vi;
+	float  vo_prev;
+	float  vo;
+	float  fcutoff;
+	float  fs;
+} OneOrderRcLpfHander;
+
+void OneOrderRcLpfInit(OneOrderRcLpfHander* hander,float cutoff_fre,float sample);
+float OneOrderRcLpfFun(OneOrderRcLpfHander *hander);
 #endif