|
|
|
@@ -0,0 +1,154 @@ |
|
|
|
/* Audio Library for Teensy 3.X |
|
|
|
* Copyright (c) 2014, Paul Stoffregen, paul@pjrc.com |
|
|
|
* |
|
|
|
* Development of this audio library was funded by PJRC.COM, LLC by sales of |
|
|
|
* Teensy and Audio Adaptor boards. Please support PJRC's efforts to develop |
|
|
|
* open source software by purchasing Teensy or other PJRC products. |
|
|
|
* |
|
|
|
* Permission is hereby granted, free of charge, to any person obtaining a copy |
|
|
|
* of this software and associated documentation files (the "Software"), to deal |
|
|
|
* in the Software without restriction, including without limitation the rights |
|
|
|
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
|
|
|
* copies of the Software, and to permit persons to whom the Software is |
|
|
|
* furnished to do so, subject to the following conditions: |
|
|
|
* |
|
|
|
* The above copyright notice, development funding notice, and this permission |
|
|
|
* notice shall be included in all copies or substantial portions of the Software. |
|
|
|
* |
|
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
|
|
|
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
|
|
|
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
|
|
|
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
|
|
|
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
|
|
|
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
|
|
|
* THE SOFTWARE. |
|
|
|
*/ |
|
|
|
|
|
|
|
#include "filter_variable.h" |
|
|
|
#include "utility/dspinst.h" |
|
|
|
|
|
|
|
|
|
|
|
// State Variable Filter (Chamberlin) with 2X oversampling |
|
|
|
// http://www.musicdsp.org/showArchiveComment.php?ArchiveID=92 |
|
|
|
|
|
|
|
//#define MULT(a, b) (int32_t)(((int64_t)(a) * (b)) >> 30) |
|
|
|
#define MULT(a, b) (multiply_32x32_rshift32_rounded(a, b) << 2) |
|
|
|
|
|
|
|
static bool first = true; |
|
|
|
|
|
|
|
void AudioFilterStateVariable::update_fixed(const int16_t *in, |
|
|
|
int16_t *lp, int16_t *bp, int16_t *hp) |
|
|
|
{ |
|
|
|
const int16_t *end = in + AUDIO_BLOCK_SAMPLES; |
|
|
|
int32_t input, inputprev; |
|
|
|
int32_t lowpass, bandpass, highpass; |
|
|
|
int32_t lowpasstmp, bandpasstmp, highpasstmp; |
|
|
|
int32_t fmult, damp; |
|
|
|
|
|
|
|
fmult = setting_fmult; |
|
|
|
damp = setting_damp; |
|
|
|
inputprev = state_inputprev; |
|
|
|
lowpass = state_lowpass; |
|
|
|
bandpass = state_bandpass; |
|
|
|
|
|
|
|
do { |
|
|
|
input = (*in++) << 12; |
|
|
|
lowpass = lowpass + MULT(fmult, bandpass); |
|
|
|
highpass = ((input + inputprev)>>1) - lowpass - MULT(damp, bandpass); |
|
|
|
inputprev = input; |
|
|
|
bandpass = bandpass + MULT(fmult, highpass); |
|
|
|
lowpasstmp = lowpass; |
|
|
|
bandpasstmp = bandpass; |
|
|
|
highpasstmp = highpass; |
|
|
|
lowpass = lowpass + MULT(fmult, bandpass); |
|
|
|
highpass = input - lowpass - MULT(damp, bandpass); |
|
|
|
bandpass = bandpass + MULT(fmult, highpass); |
|
|
|
lowpasstmp = signed_saturate_rshift(lowpass+lowpasstmp, 16, 13); |
|
|
|
bandpasstmp = signed_saturate_rshift(bandpass+bandpasstmp, 16, 13); |
|
|
|
highpasstmp = signed_saturate_rshift(highpass+highpasstmp, 16, 13); |
|
|
|
*lp++ = lowpasstmp; |
|
|
|
*bp++ = bandpasstmp; |
|
|
|
*hp++ = highpasstmp; |
|
|
|
#if 0 |
|
|
|
if (first) { |
|
|
|
Serial.print(input >> 12); |
|
|
|
Serial.print(", "); |
|
|
|
Serial.print(lowpasstmp); |
|
|
|
Serial.print(", "); |
|
|
|
Serial.print(bandpasstmp); |
|
|
|
Serial.print(", "); |
|
|
|
Serial.print(highpasstmp); |
|
|
|
Serial.println(); |
|
|
|
} |
|
|
|
#endif |
|
|
|
} while (in < end); |
|
|
|
|
|
|
|
state_inputprev = inputprev; |
|
|
|
state_lowpass = lowpass; |
|
|
|
state_bandpass = bandpass; |
|
|
|
first = false; |
|
|
|
} |
|
|
|
|
|
|
|
void AudioFilterStateVariable::update_variable(const int16_t *in, |
|
|
|
const int16_t *ctl, int16_t *lp, int16_t *bp, int16_t *hp) |
|
|
|
{ |
|
|
|
// TODO: implement control signal modulation of corner frequency |
|
|
|
update_fixed(in, lp, bp, hp); |
|
|
|
} |
|
|
|
|
|
|
|
void AudioFilterStateVariable::update(void) |
|
|
|
{ |
|
|
|
audio_block_t *input_block=NULL, *control_block=NULL; |
|
|
|
audio_block_t *lowpass_block=NULL, *bandpass_block=NULL, *highpass_block=NULL; |
|
|
|
|
|
|
|
input_block = receiveReadOnly(0); |
|
|
|
control_block = receiveReadOnly(1); |
|
|
|
if (!input_block) { |
|
|
|
if (control_block) release(control_block); |
|
|
|
return; |
|
|
|
} |
|
|
|
lowpass_block = allocate(); |
|
|
|
if (!lowpass_block) { |
|
|
|
release(input_block); |
|
|
|
if (control_block) release(control_block); |
|
|
|
return; |
|
|
|
} |
|
|
|
bandpass_block = allocate(); |
|
|
|
if (!bandpass_block) { |
|
|
|
release(input_block); |
|
|
|
release(lowpass_block); |
|
|
|
if (control_block) release(control_block); |
|
|
|
return; |
|
|
|
} |
|
|
|
highpass_block = allocate(); |
|
|
|
if (!highpass_block) { |
|
|
|
release(input_block); |
|
|
|
release(lowpass_block); |
|
|
|
release(bandpass_block); |
|
|
|
if (control_block) release(control_block); |
|
|
|
return; |
|
|
|
} |
|
|
|
|
|
|
|
if (control_block) { |
|
|
|
update_variable(input_block->data, |
|
|
|
control_block->data, |
|
|
|
lowpass_block->data, |
|
|
|
bandpass_block->data, |
|
|
|
highpass_block->data); |
|
|
|
release(control_block); |
|
|
|
} else { |
|
|
|
update_fixed(input_block->data, |
|
|
|
lowpass_block->data, |
|
|
|
bandpass_block->data, |
|
|
|
highpass_block->data); |
|
|
|
} |
|
|
|
release(input_block); |
|
|
|
transmit(lowpass_block, 0); |
|
|
|
release(lowpass_block); |
|
|
|
transmit(bandpass_block, 1); |
|
|
|
release(bandpass_block); |
|
|
|
transmit(highpass_block, 2); |
|
|
|
release(highpass_block); |
|
|
|
return; |
|
|
|
} |
|
|
|
|
PaulStoffregen
10 vuotta sitten