Move IIR struct and configs to common/.

2026-09-10 08:39:29 +00:00 · 2016-01-29 15:43:39 -08:00
parent db642cac8d
commit 01e14ecbcf
3 changed files with 0 additions and 0 deletions
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
+ *
+ * This file is part of PortaPack.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include "dsp_iir.hpp"
+
+#include <hal.h>
+
+void IIRBiquadFilter::configure(const iir_biquad_config_t& new_config) {
+	config = new_config;
+}
+
+void IIRBiquadFilter::execute(const buffer_f32_t& buffer_in, const buffer_f32_t& buffer_out) {
+	const auto a_ = config.a;
+	const auto b_ = config.b;
+	
+	auto x_ = x;
+	auto y_ = y;
+
+	// TODO: Assert that buffer_out.count == buffer_in.count.
+	for(size_t i=0; i<buffer_out.count; i++) {
+		x_[0] = x_[1];
+		x_[1] = x_[2];
+		x_[2] = buffer_in.p[i];
+
+		y_[0] = y_[1];
+		y_[1] = y_[2];
+		y_[2] = b_[0] * x_[2] + b_[1] * x_[1] + b_[2] * x_[0]
+		                      - a_[1] * y_[1] - a_[2] * y_[0];
+
+		buffer_out.p[i] = y_[2];
+	}
+
+	x = x_;
+	y = y_;
+}
+
+void IIRBiquadFilter::execute_in_place(const buffer_f32_t& buffer) {
+	execute(buffer, buffer);
+}
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
+ *
+ * This file is part of PortaPack.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __DSP_IIR_H__
+#define __DSP_IIR_H__
+
+#include <array>
+
+#include "dsp_types.hpp"
+
+struct iir_biquad_config_t {
+	std::array<float, 3> b;
+	std::array<float, 3> a;
+};
+
+constexpr iir_biquad_config_t iir_config_passthrough {
+	{ { 1.0f, 0.0f, 0.0f } },
+	{ { 0.0f, 0.0f, 0.0f } },
+};
+
+constexpr iir_biquad_config_t iir_config_no_pass {
+	{ { 0.0f, 0.0f, 0.0f } },
+	{ { 0.0f, 0.0f, 0.0f } },
+};
+
+class IIRBiquadFilter {
+public:
+	// http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt
+	constexpr IIRBiquadFilter(
+	) : IIRBiquadFilter(iir_config_no_pass)
+	{
+	}
+
+	// Assume all coefficients are normalized so that a0=1.0
+	constexpr IIRBiquadFilter(
+		const iir_biquad_config_t& config
+	) : config(config)
+	{
+	}
+
+	void configure(const iir_biquad_config_t& new_config);
+
+	void execute(const buffer_f32_t& buffer_in, const buffer_f32_t& buffer_out);
+	void execute_in_place(const buffer_f32_t& buffer);
+
+private:
+	iir_biquad_config_t config;
+	std::array<float, 3> x { { 0.0f, 0.0f, 0.0f } };
+	std::array<float, 3> y { { 0.0f, 0.0f, 0.0f } };
+};
+
+#endif/*__DSP_IIR_H__*/
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
+ *
+ * This file is part of PortaPack.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __DSP_IIR_CONFIG_H__
+#define __DSP_IIR_CONFIG_H__
+
+#include "dsp_iir.hpp"
+
+// scipy.signal.butter(2, 30 / 24000.0, 'highpass', analog=False)
+constexpr iir_biquad_config_t audio_48k_hpf_30hz_config {
+	{  0.99722705f, -1.99445410f,  0.99722705f },
+	{  1.00000000f, -1.99444641f,  0.99446179f }
+};
+
+// scipy.signal.butter(2, 300 / 24000.0, 'highpass', analog=False)
+constexpr iir_biquad_config_t audio_48k_hpf_300hz_config {
+	{  0.97261390f, -1.94522780f,  0.97261390f },
+	{  1.00000000f, -1.94447766f,  0.94597794f }
+};
+
+// scipy.signal.butter(2, 300 / 8000.0, 'highpass', analog=False)
+constexpr iir_biquad_config_t audio_16k_hpf_300hz_config {
+	{  0.92006616f, -1.84013232f,  0.92006616f },
+	{  1.00000000f, -1.83373266f,  0.84653197f }
+};
+
+// scipy.signal.butter(2, 300 / 4000.0, 'highpass', analog=False)
+constexpr iir_biquad_config_t audio_8k_hpf_300hz_config {
+	{  0.84645925f, -1.69291851f,  0.84645925f },
+	{  1.00000000f, -1.66920314f,  0.71663387f }
+};
+
+// scipy.signal.iirdesign(wp=8000 / 24000.0, ws= 4000 / 24000.0, gpass=1, gstop=18, ftype='ellip')
+constexpr iir_biquad_config_t non_audio_hpf_config {
+	{  0.51891061f, -0.95714180f,  0.51891061f },
+	{  1.0f       , -0.79878302f,  0.43960231f }
+};
+
+// scipy.signal.butter(1, 300 / 24000.0, 'lowpass', analog=False)
+// NOTE: Technically, order-1 filter, b[2] = a[2] = 0.
+constexpr iir_biquad_config_t audio_48k_deemph_300_6_config {
+	{  0.01925927f,  0.01925927f,  0.00000000f },
+	{  1.00000000f, -0.96148145f,  0.00000000f }
+};
+
+// scipy.signal.butter(1, 300 / 8000.0, 'lowpass', analog=False)
+// NOTE: Technically, order-1 filter, b[2] = a[2] = 0.
+constexpr iir_biquad_config_t audio_16k_deemph_300_6_config {
+	{  0.05568894f,  0.05568894f,  0.00000000f },
+	{  1.00000000f, -0.88862213f,  0.00000000f }
+};
+
+// scipy.signal.butter(1, 300 / 4000.0, 'lowpass', analog=False)
+// NOTE: Technically, order-1 filter, b[2] = a[2] = 0.
+constexpr iir_biquad_config_t audio_8k_deemph_300_6_config {
+	{  0.10583178f,  0.10583178f,  0.00000000f },
+	{  1.00000000f, -0.78833643f,  0.00000000f }
+};
+
+// 75us RC time constant, used in broadcast FM in Americas, South Korea
+// scipy.signal.butter(1, 2122 / 24000.0, 'lowpass', analog=False)
+// NOTE: Technically, order-1 filter, b[2] = a[2] = 0.
+constexpr iir_biquad_config_t audio_48k_deemph_2122_6_config {
+	{  0.12264116f,  0.12264116f,  0.00000000f },
+	{  1.00000000f, -0.75471767f,  0.00000000f }
+};
+
+#endif/*__DSP_IIR_CONFIG_H__*/