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path: root/src/drivers/lsm303d/iirFilter.c
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-rw-r--r--src/drivers/lsm303d/iirFilter.c255
1 files changed, 0 insertions, 255 deletions
diff --git a/src/drivers/lsm303d/iirFilter.c b/src/drivers/lsm303d/iirFilter.c
deleted file mode 100644
index 8311f14d6..000000000
--- a/src/drivers/lsm303d/iirFilter.c
+++ /dev/null
@@ -1,255 +0,0 @@
-#include "math.h"
-#include "string.h"
-#include "iirFilter.h"
-
-///////////////////////////////////////////////////////////////////////////////
-// Internal function prototypes
-
-int btZpgcToZpgd(const TF_ZPG_t *pkZpgc, double Ts, TF_ZPG_t *pZpgd);
-
-int btDifcToZpgd(const TF_DIF_t *pkDifc, double Ts, TF_ZPG_t *pZpgd);
-
-int tPolydToFil(const TF_POLY_t *pkPolyd, FIL_T *pFilt);
-
-int tZpgxToPolyx(const TF_ZPG_t *pkZpg, TF_POLY_t *pPoly);
-
-///////////////////////////////////////////////////////////////////////////////
-// external functions
-
-int testFunction()
-{
- printf("TEST\n");
- return 1;
-}
-
-int initFilter(const TF_DIF_t *pDifc, double Ts, FIL_T *pFilt)
-{
- TF_POLY_t polyd;
- TF_ZPG_t zpgd;
-
- memset(pFilt, 0, sizeof(FIL_T));
-
- // perform bilinear transform with frequency pre warping
- btDifcToZpgd(pDifc, Ts, &zpgd);
-
- // calculate polynom
- tZpgxToPolyx(&zpgd, &polyd);
-
- // set the filter parameters
- tPolydToFil(&polyd, pFilt);
-
- return 1;
-}
-
-// run filter using inp, return output of the filter
-float updateFilter(FIL_T *pFilt, float inp)
-{
- float outp = 0;
- int idx; // index used for different things
- int i; // loop variable
-
- // Store the input to the input array
- idx = pFilt->inpCnt % MAX_LENGTH;
- pFilt->inpData[idx] = inp;
-
- // calculate numData * inpData
- for (i = 0; i < pFilt->numLength; i++)
- {
- // index of inp array
- idx = (pFilt->inpCnt + i - pFilt->numLength + 1) % MAX_LENGTH;
- outp += pFilt->numData[i] * pFilt->inpData[idx];
- }
-
- // calculate denData * outData
- for (i = 0; i < pFilt->denLength; i++)
- {
- // index of inp array
- idx = (pFilt->inpCnt + i - pFilt->denLength) % MAX_LENGTH;
- outp -= pFilt->denData[i] * pFilt->outData[idx];
- }
-
- // store the ouput data to the output array
- idx = pFilt->inpCnt % MAX_LENGTH;
- pFilt->outData[idx] = outp;
-
- pFilt->inpCnt += 1;
-
- return outp;
-}
-
-///////////////////////////////////////////////////////////////////////////////
-// Internal functions
-
-int tPolydToFil(const TF_POLY_t *pkPolyd, FIL_T *pFilt)
-{
- double gain;
- int i;
-
- if (pkPolyd->Ts < 0)
- {
- return 0;
- }
-
- // initialize filter to 0
- memset(pFilt, 0, sizeof(FIL_T));
-
- gain = pkPolyd->denData[pkPolyd->denLength - 1];
- pFilt->Ts = pkPolyd->Ts;
-
- pFilt->denLength = pkPolyd->denLength - 1;
- pFilt->numLength = pkPolyd->numLength;
-
- for (i = 0; i < pkPolyd->numLength; i++)
- {
- pFilt->numData[i] = pkPolyd->numData[i] / gain;
- }
-
- for (i = 0; i < (pkPolyd->denLength - 1); i++)
- {
- pFilt->denData[i] = pkPolyd->denData[i] / gain;
- }
-}
-
-// bilinear transformation of poles and zeros
-int btDifcToZpgd(const TF_DIF_t *pkDifc,
- double Ts,
- TF_ZPG_t *pZpgd)
-{
- TF_ZPG_t zpgc;
- int totDiff;
- int i;
-
- zpgc.zerosLength = 0;
- zpgc.polesLength = 0;
- zpgc.gain = pkDifc->gain;
- zpgc.Ts = pkDifc->Ts;
-
- // Total number of differentiators / integerators
- // positive diff, negative integ, 0 for no int/diff
- totDiff = pkDifc->numDiff - pkDifc->numInt + pkDifc->highpassLength;
-
- while (zpgc.zerosLength < totDiff)
- {
- zpgc.zerosData[zpgc.zerosLength] = 0;
- zpgc.zerosLength++;
- }
- while (zpgc.polesLength < -totDiff)
- {
- zpgc.polesData[zpgc.polesLength] = 0;
- zpgc.polesLength++;
- }
-
- // The next step is to calculate the poles
- // This has to be done for the highpass and lowpass filters
- // As we are using bilinear transformation there will be frequency
- // warping which has to be accounted for
- for (i = 0; i < pkDifc->lowpassLength; i++)
- {
- // pre-warping:
- double freq = 2.0 / Ts * tan(pkDifc->lowpassData[i] * 2.0 * M_PI * Ts / 2.0);
- // calculate pole:
- zpgc.polesData[zpgc.polesLength] = -freq;
- // adjust gain such that lp has gain = 1 for low frequencies
- zpgc.gain *= freq;
- zpgc.polesLength++;
- }
- for (i = 0; i < pkDifc->highpassLength; i++)
- {
- // pre-warping
- double freq = 2.0 / Ts * tan(pkDifc->highpassData[i] * 2.0 * M_PI * Ts / 2.0);
- // calculate pole:
- zpgc.polesData[zpgc.polesLength] = -freq;
- // gain does not have to be adjusted
- zpgc.polesLength++;
- }
-
- return btZpgcToZpgd(&zpgc, Ts, pZpgd);
-}
-
-// bilinear transformation of poles and zeros
-int btZpgcToZpgd(const TF_ZPG_t *pkZpgc,
- double Ts,
- TF_ZPG_t *pZpgd)
-{
- int i;
-
- // init digital gain
- pZpgd->gain = pkZpgc->gain;
-
- // transform the poles
- pZpgd->polesLength = pkZpgc->polesLength;
- for (i = 0; i < pkZpgc->polesLength; i++)
- {
- pZpgd->polesData[i] = (2.0 / Ts + pkZpgc->polesData[i]) / (2.0 / Ts - pkZpgc->polesData[i]);
- pZpgd->gain /= (2.0 / Ts - pkZpgc->polesData[i]);
- }
-
- // transform the zeros
- pZpgd->zerosLength = pkZpgc->zerosLength;
- for (i = 0; i < pkZpgc->zerosLength; i++)
- {
- pZpgd->zerosData[i] = (2.0 / Ts + pkZpgc->zerosData[i]) / (2.0 / Ts + pkZpgc->zerosData[i]);
- pZpgd->gain *= (2.0 / Ts - pkZpgc->zerosData[i]);
- }
-
- // if we don't have the same number of poles as zeros we have to add
- // poles or zeros due to the bilinear transformation
- while (pZpgd->zerosLength < pZpgd->polesLength)
- {
- pZpgd->zerosData[pZpgd->zerosLength] = -1.0;
- pZpgd->zerosLength++;
- }
- while (pZpgd->zerosLength > pZpgd->polesLength)
- {
- pZpgd->polesData[pZpgd->polesLength] = -1.0;
- pZpgd->polesLength++;
- }
-
- pZpgd->Ts = Ts;
-
- return 1;
-}
-
-// calculate polynom from zero, pole, gain form
-int tZpgxToPolyx(const TF_ZPG_t *pkZpg, TF_POLY_t *pPoly)
-{
- int i, j; // counter variable
- double tmp0, tmp1, gain;
-
- // copy Ts
- pPoly->Ts = pkZpg->Ts;
-
- // calculate denominator polynom
- pPoly->denLength = 1;
- pPoly->denData[0] = 1.0;
- for (i = 0; i < pkZpg->polesLength; i++)
- {
- // init temporary variable
- tmp0 = 0.0;
- // increase the polynom by 1
- pPoly->denData[pPoly->denLength] = 0;
- pPoly->denLength++;
- for (j = 0; j < pPoly->denLength; j++)
- {
- tmp1 = pPoly->denData[j];
- pPoly->denData[j] = tmp1 * -pkZpg->polesData[i] + tmp0;
- tmp0 = tmp1;
- }
- }
-
- // calculate numerator polynom
- pPoly->numLength = 1;
- pPoly->numData[0] = pkZpg->gain;
- for (i = 0; i < pkZpg->zerosLength; i++)
- {
- tmp0 = 0.0;
- pPoly->numData[pPoly->numLength] = 0;
- pPoly->numLength++;
- for (j = 0; j < pPoly->numLength; j++)
- {
- tmp1 = pPoly->numData[j];
- pPoly->numData[j] = tmp1 * -pkZpg->zerosData[i] + tmp0;
- tmp0 = tmp1;
- }
- }
-}