src/main/common/filter.h

   1 /*
   2  * This file is part of Cleanflight.
   3  *
   4  * Cleanflight is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * Cleanflight is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with Cleanflight.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #pragma once
  19
  20 typedef struct filterStatePt1_s {
  21         float state;
  22         float RC;
  23         float constdT;
  24 } filterStatePt1_t;
  25
  26 /* this holds the data required to update samples thru a filter */
  27 typedef struct biquad_s {
  28     float b0, b1, b2, a1, a2;
  29     float d1, d2;
  30 } biquad_t;
  31
  32 float filterApplyPt1(float input, filterStatePt1_t *filter, float f_cut, float dt);
  33 float filterApplyPt1WithRateLimit(float input, filterStatePt1_t *filter, float f_cut, float rate_limit, float dT);
  34 void filterResetPt1(filterStatePt1_t *filter, float input);
  35
  36 void filterInitBiQuad(uint8_t filterCutFreq, biquad_t *newState, int16_t samplingRate);
  37 float filterApplyBiQuad(float sample, biquad_t *state);
  38
  39 void filterUpdateFIR(int filterLength, float *shiftBuf, float newSample);
  40 float filterApplyFIR(int filterLength, const float *shiftBuf, const float *coeffBuf, float commonMultiplier);