Extract WidebandFMAudio into separate files.

firmware/baseband/proc_wfm_audio.cpp

@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2014 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 "proc_wfm_audio.hpp"
+
+#include <cstdint>
+
+void WidebandFMAudio::execute(buffer_c8_t buffer) {
+	auto decimator_out = decimator.execute(buffer);
+
+	const buffer_s16_t work_audio_buffer {
+		(int16_t*)decimator_out.p,
+		sizeof(*decimator_out.p) * decimator_out.count
+	};
+
+	auto channel = decimator_out;
+
+	// TODO: Feed channel_stats post-decimation data?
+	feed_channel_stats(channel);
+	//feed_channel_spectrum(channel);
+
+	/* 768kHz complex<int16_t>[512]
+	 * -> FM demodulation
+	 * -> 768kHz int16_t[512] */
+	/* TODO: To improve adjacent channel rejection, implement complex channel filter:
+	 *		pass < +/- 100kHz, stop > +/- 200kHz
+	 */
+
+	auto audio_oversampled = demod.execute(decimator_out, work_audio_buffer);
+
+	/* 768kHz int16_t[512]
+	 * -> 4th order CIC decimation by 2, gain of 1
+	 * -> 384kHz int16_t[256] */
+	auto audio_8fs = audio_dec_1.execute(audio_oversampled, work_audio_buffer);
+
+	/* 384kHz int16_t[256]
+	 * -> 4th order CIC decimation by 2, gain of 1
+	 * -> 192kHz int16_t[128] */
+	auto audio_4fs = audio_dec_2.execute(audio_8fs, work_audio_buffer);
+
+	/* 192kHz int16_t[128]
+	 * -> 4th order CIC decimation by 2, gain of 1
+	 * -> 96kHz int16_t[64] */
+	auto audio_2fs = audio_dec_3.execute(audio_4fs, work_audio_buffer);
+
+	/* 96kHz int16_t[64]
+	 * -> FIR filter, <15kHz (0.156fs) pass, >19kHz (0.198fs) stop, gain of 1
+	 * -> 48kHz int16_t[32] */
+	auto audio = audio_filter.execute(audio_2fs, work_audio_buffer);
+
+	/* -> 48kHz int16_t[32] */
+	audio_hpf.execute_in_place(audio);
+	fill_audio_buffer(audio);
+}