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/* Audio Library for Teensy 3.X
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* Copyright (c) 2014, Paul Stoffregen, paul@pjrc.com |
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* |
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* Development of this audio library was funded by PJRC.COM, LLC by sales of |
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* Teensy and Audio Adaptor boards. Please support PJRC's efforts to develop |
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* open source software by purchasing Teensy or other PJRC products. |
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* |
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* Permission is hereby granted, free of charge, to any person obtaining a copy |
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* of this software and associated documentation files (the "Software"), to deal |
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* in the Software without restriction, including without limitation the rights |
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
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* copies of the Software, and to permit persons to whom the Software is |
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* furnished to do so, subject to the following conditions: |
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* |
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* The above copyright notice, development funding notice, and this permission |
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* notice shall be included in all copies or substantial portions of the Software. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
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* THE SOFTWARE. |
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*/ |
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#include "filter_moog.h" |
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#if defined(KINETISK) |
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void AudioFilterMoog::update_fixed(const int16_t *in,int16_t *lp) |
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{ |
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const float MAX_INT = 32678.0; |
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for (int i = 0; i < AUDIO_BLOCK_SAMPLES; i++) { |
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float cs = (float)in[i]; |
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cs=cs/MAX_INT; |
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cs = tanhf(cs * driv); |
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y_a = y_a + g * (tanhf(cs - q * ((y_d_1 + y_d)/2) - tanhf(y_a))); |
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y_b = y_b + g * (tanhf(y_a) - tanhf(y_b)); |
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y_c = y_c + g * (tanhf(y_b) - tanhf(y_c)); |
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y_d_1 = y_d; |
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y_d = y_d + g * (tanhf(y_c) - tanhf(y_d)); |
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cs=y_d*MAX_INT; |
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lp[i] = (int16_t)cs; |
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} |
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} |
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void AudioFilterMoog::update_variable(const int16_t *in,const int16_t *ctl, int16_t *lp) |
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{ |
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const float MAX_INT = 32678.0; |
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int over=1; |
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float cs = (float)ctl[0]; |
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cs=cs/MAX_INT; |
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float nf=basef*(exp2f(cs*oct)); |
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// Serial.println(nf);
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frequency(nf,false); |
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update_fixed(in,lp) ; |
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} |
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void AudioFilterMoog::update(void) |
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{ |
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audio_block_t *input_block=NULL, *control_block=NULL; |
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audio_block_t *lowpass_block=NULL; |
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input_block = receiveReadOnly(0); |
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control_block = receiveReadOnly(1); |
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if (!input_block) { |
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if (control_block) release(control_block); |
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return; |
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} |
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lowpass_block = allocate(); |
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if (!lowpass_block) { |
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release(input_block); |
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if (control_block) release(control_block); |
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return; |
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} |
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if (control_block) { |
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update_variable(input_block->data, control_block->data, lowpass_block->data); |
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release(control_block); |
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} else { |
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update_fixed(input_block->data, lowpass_block->data); |
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} |
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release(input_block); |
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transmit(lowpass_block, 0); |
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release(lowpass_block); |
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return; |
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} |
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#elif defined(KINETISL) |
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void AudioFilterMoog::update(void) |
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{ |
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audio_block_t *block; |
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block = receiveReadOnly(0); |
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if (block) release(block); |
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block = receiveReadOnly(1); |
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if (block) release(block); |
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} |
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#endif |
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#ifndef filter_moog_h_ |
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#define filter_moog_h_ |
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#include "Arduino.h" |
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#include "AudioStream.h" |
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#include "arm_math.h" |
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class AudioFilterMoog: public AudioStream |
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{ |
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float g; |
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float q; |
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float driv; |
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float oct; |
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float basef; |
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float y_a; |
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float y_b; |
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float y_c; |
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float y_d; |
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float y_d_1; |
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public: |
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AudioFilterMoog() : AudioStream(2, inputQueueArray) { |
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frequency(1000); |
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resonance(1); |
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drive(1); |
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octave(1); |
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y_a = 0; |
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y_b = 0; |
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y_c = 0; |
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y_d = 0; |
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y_d_1 = 0; |
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} |
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void resonance(float qi) { |
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if (qi < 0.7) qi = 0.7; |
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else if (qi > 5.0) qi = 5.0; |
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q=qi; |
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} |
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void drive(float d) { |
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if (d > 10.0f) d = 10.0f; |
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if (d < 0.1f) d = 0.1f; |
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driv = d; |
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} |
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void octave(float n) { |
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if (n < 0.0) n = 0.0; |
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else if (n > 6.9999) n = 6.9999; |
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oct=n; |
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} |
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void frequency(float freq,bool setf=true) { |
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if (freq < 20.0) freq = 20.0; |
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else if (freq > AUDIO_SAMPLE_RATE_EXACT/2.5) freq = AUDIO_SAMPLE_RATE_EXACT/2.5; |
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g = 1 - expf(-2 * tanf(2 * M_PI * freq/(2 * AUDIO_SAMPLE_RATE_EXACT))); |
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if(setf) |
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basef=freq; |
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} |
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virtual void update(void); |
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private: |
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void update_fixed(const int16_t *in,int16_t *lp); |
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void update_variable(const int16_t *in, const int16_t *ctl, int16_t *lp); |
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audio_block_t *inputQueueArray[2]; |
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}; |
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#endif |
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