robin/two_pole_dc_pass
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Robin. P. Clark 2019-09-10 11:38:04 +01:00
parent 7562cf3246
commit c1bded0f5a
2 changed files with 20 additions and 4 deletions
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two_pole_7_8.c
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@ -146,7 +146,13 @@ two_pole_7_8_zg ( int16_t input ) { // with zero guard
return y0>>(BIN_FRACS+3); // divide back down for scaling and then divide by 8 filter gain // *res;
}
#define BIN_FRACS_15_16 9
//
// At 20,000 TDS with 1500 noise this caused instability in the filter
// when BINFRACS was set to 9. As the input is not divided
// its already 8 bits (*256) high. Try BINFRACS at 2.
//
#define BIN_FRACS_15_16 2
// this is a 64 bit machine (the pi)
//
@ -204,9 +210,6 @@ two_pole_15_16 ( int16_t input ) {
return y0>>(BIN_FRACS_15_16); // divide back down for scaling and then divide by 8 filter gain // *res;
}
#define RAND_RANGE 500
#define DC_TERM 1500
int zero_only_2 ( int input )
@ -284,6 +287,19 @@ int zero_only_4 ( int input )
return res/16;
}
// This was initially tested at 1500 TDS with \pm 500 noise
// Tests at 15000 with \pm 1500 noise at BINFRACS 9 caused instability in the two pole 15 16
// BINFRACS down to 2 for that filter.
// #define RAND_RANGE 500
// #define DC_TERM 1500
#define RAND_RANGE 500
#define DC_TERM 1000
int main () {
int i, zo2,zo3,zo4;