robin/two_pole_dc_pass
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DC_TERM now a #define

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Robin P. Clark 2019-08-26 07:02:34 +01:00
parent 331880decd
commit 8d26c1ebf4
1 changed files with 12 additions and 7 deletions
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19
two_pole_7_8.c
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@ -1,6 +1,6 @@
#include <stdlib.h>
#include <stdint.h> #include <stdint.h>
#include <stdio.h> #include <stdio.h>
#include <math.h> #include <math.h>
@ -33,7 +33,7 @@ two_pole_7_8 ( int16_t input ) {
// the minus 3 divides by 8 : DOUBLE POLE // the minus 3 divides by 8 : DOUBLE POLE
x0 <<= (BIN_FRACS-3) ; // now all calculations are done times BIN_FRACS^2 x0 <<= (BIN_FRACS-3) ; // now all calculations are done times BIN_FRACS^2
// this works really well WHY? // this works stabley but not well WHY?
//y0 = x0 + y1-(y1>>3) - ((y2>>1) + (y2>>2) + (y2>>6)); //y0 = x0 + y1-(y1>>3) - ((y2>>1) + (y2>>2) + (y2>>6));
// should be // should be
@ -41,7 +41,7 @@ two_pole_7_8 ( int16_t input ) {
// //
// //
// OK this works well // OK this works well
y0 = x0 + (14.0 / 8.0) * (double) y1 - (49.0/64.0) * (double) y2; // y0 = x0 + (14.0 / 8.0) * (double) y1 - (49.0/64.0) * (double) y2;
@ -77,17 +77,22 @@ two_pole_7_8 ( int16_t input ) {
return y0>>(BIN_FRACS+3); // divide back down for scaling and then divide by 8 filter gain // *res; return y0>>(BIN_FRACS+3); // divide back down for scaling and then divide by 8 filter gain // *res;
} }
#define RAND_RANGE 100
#define DC_TERM 1000
int main () { int main () {
int i; int i;
int16_t val,res, res34, res78; int16_t val,res, res34, res78,rr;
for (i=0;i<1000;i++) { for (i=0;i<1000;i++) {
// ramp + some sine
val = sin ( (double)i*10.0 / (3.142 * 2.0) ) * 10.0 + 25000 ; val = sin ( (double)i*10.0 / (3.142 * 2.0) ) * 10.0 + DC_TERM ;
rr = rand() % (RAND_RANGE*2);
rr -= RAND_RANGE;
val += rr;
// fast sine // fast sine
//val = sin ( ((double)i*10.0) / (3.142 * 2.0) ) * 10000; //val = sin ( ((double)i*10.0) / (3.142 * 2.0) ) * 10000;