12 changed files with 378 additions and 112 deletions
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4.vscode/settings.json
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8README.md
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174app/app.uvoptx
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16app/app.uvprojx
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2app/src/basic/ads1293/ads1293.h
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2app/src/basic/device_version_info_mgr.c
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113app/src/basic/filters.c
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56app/src/basic/filters.h
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2app/src/board/board.h
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4app/src/board/board_beep_ctrl.c
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10app/src/device_ctrl_service.c
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99app/src/heart_wave_sample_service.c
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#include "filters.h" |
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#include <stdint.h> |
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#include <string.h> |
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#define PI 3.14159265358979323846 |
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/******************************************************************************************************** |
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* LOW PASS FILTER |
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********************************************************************************************************/ |
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void LPFilter_Init(LPFilter *filter, float cutoffFreqHz, float sampleTimeS) { |
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float RC = 0.0; |
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RC = 1.0 / (2 * PI * cutoffFreqHz); |
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filter->coef[0] = sampleTimeS / (sampleTimeS + RC); |
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filter->coef[1] = RC / (sampleTimeS + RC); |
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filter->v_out[0] = 0.0; |
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filter->v_out[1] = 0.0; |
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} |
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float LPFilter_Update(LPFilter *filter, float v_in) { |
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filter->v_out[1] = filter->v_out[0]; |
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filter->v_out[0] = (filter->coef[0] * v_in) + (filter->coef[1] * filter->v_out[1]); |
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return (filter->v_out[0]); |
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} |
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/******************************************************************************************************** |
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* HIGH PASS FILTER |
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********************************************************************************************************/ |
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void HPFilter_Init(HPFilter *filter, float cutoffFreqHz, float sampleTimeS) { |
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float RC = 0.0; |
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RC = 1.0 / (2 * PI * cutoffFreqHz); |
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filter->coef = RC / (sampleTimeS + RC); |
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filter->v_in[0] = 0.0; |
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filter->v_in[1] = 0.0; |
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filter->v_out[0] = 0.0; |
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filter->v_out[1] = 0.0; |
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} |
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float HPFilter_Update(HPFilter *filter, float v_in) { |
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filter->v_in[1] = filter->v_in[0]; |
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filter->v_in[0] = v_in; |
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filter->v_out[1] = filter->v_out[0]; |
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filter->v_out[0] = filter->coef * (filter->v_in[0] - filter->v_in[1] + filter->v_out[1]); |
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return (filter->v_out[0]); |
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} |
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/******************************************************************************************************** |
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* BAND PASS FILTER |
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********************************************************************************************************/ |
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void PBFilter_Init(PBFilter *filter, float HPF_cutoffFreqHz, float LPF_cutoffFreqHz, float sampleTimeS) { |
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LPFilter_Init(&filter->lpf, LPF_cutoffFreqHz, sampleTimeS); |
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HPFilter_Init(&filter->hpf, HPF_cutoffFreqHz, sampleTimeS); |
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filter->out_in = 0.0; |
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} |
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float PBFilter_Update(PBFilter *filter, float v_in) { |
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filter->out_in = HPFilter_Update(&filter->hpf, v_in); |
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filter->out_in = LPFilter_Update(&filter->lpf, filter->out_in); |
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return (filter->out_in); |
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} |
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/******************************************************************************************************** |
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* NOTCH FILTER |
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********************************************************************************************************/ |
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void NOTCHFilter_Init(NOTCHFilter *filter, float centerFreqHz, float notchWidthHz, float sampleTimeS) { |
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// filter frequency to angular (rad/s) |
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float w0_rps = 2.0 * PI * centerFreqHz; |
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float ww_rps = 2.0 * PI * notchWidthHz; |
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// pre warp center frequency |
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float w0_pw_rps = (2.0 / sampleTimeS) * tanf(0.5 * w0_rps * sampleTimeS); |
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// computing filter coefficients |
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filter->alpha = 4.0 + w0_rps * w0_pw_rps * sampleTimeS * sampleTimeS; |
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filter->beta = 2.0 * ww_rps * sampleTimeS; |
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// clearing input and output buffers |
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for (uint8_t n = 0; n < 3; n++) { |
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filter->vin[n] = 0; |
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filter->vout[n] = 0; |
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} |
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} |
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float NOTCHFilter_Update(NOTCHFilter *filter, float vin) { |
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// shifting samples |
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filter->vin[2] = filter->vin[1]; |
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filter->vin[1] = filter->vin[0]; |
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filter->vout[2] = filter->vout[1]; |
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filter->vout[1] = filter->vout[0]; |
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filter->vin[0] = vin; |
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// compute new output |
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filter->vout[0] = (filter->alpha * filter->vin[0] + 2.0 * (filter->alpha - 8.0) * filter->vin[1] + filter->alpha * filter->vin[2] - (2.0f * (filter->alpha - 8.0) * filter->vout[1] + (filter->alpha - filter->beta) * filter->vout[2])) / (filter->alpha + filter->beta); |
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return (filter->vout[0]); |
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} |
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#pragma once |
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#include <stdint.h> |
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/******************************************************************************************************** |
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* LOW PASS FILTER |
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********************************************************************************************************/ |
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typedef struct { |
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float coef[2]; |
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float v_out[2]; |
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} LPFilter; |
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void LPFilter_Init(LPFilter *filter, float cutoffFreqHz, float sampleTimeS); |
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float LPFilter_Update(LPFilter *filter, float v_in); |
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/******************************************************************************************************** |
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* HIGH PASS FILTER |
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********************************************************************************************************/ |
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typedef struct { |
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float coef; |
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float v_out[2]; |
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float v_in[2]; |
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} HPFilter; |
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void HPFilter_Init(HPFilter *filter, float cutoffFreqHz, float sampleTimeS); |
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float HPFilter_Update(HPFilter *filter, float v_in); |
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/******************************************************************************************************** |
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* BAND PASS FILTER |
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********************************************************************************************************/ |
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typedef struct { |
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LPFilter lpf; |
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HPFilter hpf; |
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float out_in; |
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} PBFilter; |
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void PBFilter_Init(PBFilter *filter, float HPF_cutoffFreqHz, float LPF_cutoffFreqHz, float sampleTimeS); |
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float PBFilter_Update(PBFilter *filter, float v_in); |
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/******************************************************************************************************** |
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* NOTCH FILTER |
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********************************************************************************************************/ |
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typedef struct { |
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float alpha; |
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float beta; |
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float vin[3]; |
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float vout[3]; |
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} NOTCHFilter; |
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void NOTCHFilter_Init(NOTCHFilter *filter, float centerFreqHz, float notchWidthHz, float sampleTimeS); |
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float NOTCHFilter_Update(NOTCHFilter *filter, float vin); |
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