Extract spectrum collector from BasebandProcessor.

Code size improvement, and less confused classes. :-)

firmware/baseband/Makefile

@@ -137,6 +137,7 @@ CPPSRC = main.cpp \
          matched_filter.cpp \
          proc_am_audio.cpp \
          proc_nfm_audio.cpp \
+         spectrum_collector.cpp \
          proc_wfm_audio.cpp \
          proc_ais.cpp \
          proc_wideband_spectrum.cpp \

firmware/baseband/baseband_processor.cpp

@@ -34,31 +34,6 @@
 #include <cstddef>
 #include <algorithm>
 
-void BasebandProcessor::update_spectrum() {
-	// Called from idle thread (after EVT_MASK_SPECTRUM is flagged)
-	if( channel_spectrum_request_update ) {
-		/* Decimated buffer is full. Compute spectrum. */
-		channel_spectrum_request_update = false;
-		fft_c_preswapped(channel_spectrum);
-
-		ChannelSpectrumMessage spectrum_message;
-		for(size_t i=0; i<spectrum_message.spectrum.db.size(); i++) {
-			const auto mag2 = magnitude_squared(channel_spectrum[i]);
-			const float db = complex16_mag_squared_to_dbv_norm(mag2);
-			constexpr float mag_scale = 5.0f;
-			const unsigned int v = (db * mag_scale) + 255.0f;
-			spectrum_message.spectrum.db[i] = std::max(0U, std::min(255U, v));
-		}
-
-		/* TODO: Rename .db -> .magnitude, or something more (less!) accurate. */
-		spectrum_message.spectrum.db_count = spectrum_message.spectrum.db.size();
-		spectrum_message.spectrum.sampling_rate = channel_spectrum_sampling_rate;
-		spectrum_message.spectrum.channel_filter_pass_frequency = channel_filter_pass_frequency;
-		spectrum_message.spectrum.channel_filter_stop_frequency = channel_filter_stop_frequency;
-		shared_memory.application_queue.push(spectrum_message);
-	}
-}
-
 void BasebandProcessor::feed_channel_stats(const buffer_c16_t& channel) {
 	channel_stats.feed(
 		channel,
@@ -69,21 +44,6 @@ void BasebandProcessor::feed_channel_stats(const buffer_c16_t& channel) {
 	);
 }
 
-void BasebandProcessor::feed_channel_spectrum(
-	const buffer_c16_t& channel,
-	const uint32_t filter_pass_frequency,
-	const uint32_t filter_stop_frequency
-) {
-	channel_filter_pass_frequency = filter_pass_frequency;
-	channel_filter_stop_frequency = filter_stop_frequency;
-	channel_spectrum_decimator.feed(
-		channel,
-		[this](const buffer_c16_t& data) {
-			this->post_channel_spectrum_message(data);
-		}
-	);
-}
-
 void BasebandProcessor::fill_audio_buffer(const buffer_s16_t& audio) {
 	auto audio_buffer = audio::dma::tx_empty_buffer();;
 	for(size_t i=0; i<audio_buffer.count; i++) {
@@ -94,15 +54,6 @@ void BasebandProcessor::fill_audio_buffer(const buffer_s16_t& audio) {
 	feed_audio_stats(audio);
 }
 
-void BasebandProcessor::post_channel_spectrum_message(const buffer_c16_t& data) {
-	if( !channel_spectrum_request_update ) {
-		fft_swap(data, channel_spectrum);
-		channel_spectrum_sampling_rate = data.sampling_rate;
-		channel_spectrum_request_update = true;
-		events_flag(EVT_MASK_SPECTRUM);
-	}
-}
-
 void BasebandProcessor::feed_audio_stats(const buffer_s16_t& audio) {
 	audio_stats.feed(
 		audio,

firmware/baseband/baseband_processor.hpp

@@ -25,7 +25,6 @@
 #include "dsp_types.hpp"
 #include "complex.hpp"
 
-#include "block_decimator.hpp"
 #include "channel_stats_collector.hpp"
 #include "audio_stats_collector.hpp"
 
@@ -39,32 +38,17 @@ public:
 
 	virtual void execute(const buffer_c8_t& buffer) = 0;
 
-	void update_spectrum();
+	virtual void on_update_spectrum() { };
 
 protected:
 	void feed_channel_stats(const buffer_c16_t& channel);
 
-	void feed_channel_spectrum(
-		const buffer_c16_t& channel,
-		const uint32_t filter_pass_frequency,
-		const uint32_t filter_stop_frequency
-	);
-
 	void fill_audio_buffer(const buffer_s16_t& audio);
 
-	volatile bool channel_spectrum_request_update { false };
-	std::array<std::complex<float>, 256> channel_spectrum;
-	uint32_t channel_spectrum_sampling_rate { 0 };
-	uint32_t channel_filter_pass_frequency { 0 };
-	uint32_t channel_filter_stop_frequency { 0 };
-
 private:
-	BlockDecimator<256> channel_spectrum_decimator { 4 };
-
 	ChannelStatsCollector channel_stats;
 	AudioStatsCollector audio_stats;
 
-	void post_channel_spectrum_message(const buffer_c16_t& data);
 	void feed_audio_stats(const buffer_s16_t& audio);
 };
 

firmware/baseband/baseband_thread.cpp

@@ -68,6 +68,12 @@ void BasebandThread::set_configuration(const BasebandConfiguration& new_configur
 	baseband_configuration = new_configuration;
 }
 
+void BasebandThread::on_update_spectrum() {
+	if( baseband_processor ) {
+		baseband_processor->on_update_spectrum();
+	}	
+}
+
 void BasebandThread::run() {
 	baseband::dma::init();
 

firmware/baseband/baseband_thread.hpp

@@ -39,6 +39,8 @@ public:
 
 	void set_configuration(const BasebandConfiguration& new_configuration);
 
+	void on_update_spectrum();
+	
 	// This getter should die, it's just here to leak information to code that
 	// isn't in the right place to begin with.
 	baseband::Direction direction() const {

firmware/baseband/main.cpp

@@ -187,9 +187,8 @@ private:
 	}
 
 	void handle_spectrum() {
-		if( baseband_thread.baseband_processor ) {
-			baseband_thread.baseband_processor->update_spectrum();
-		}
+		// TODO: Send this via another message?!
+		baseband_thread.on_update_spectrum();
 	}
 };
 

firmware/baseband/proc_am_audio.cpp

@@ -38,7 +38,7 @@ void NarrowbandAMAudio::execute(const buffer_c8_t& buffer) {
 
 	// TODO: Feed channel_stats post-decimation data?
 	feed_channel_stats(channel);
-	feed_channel_spectrum(
+	channel_spectrum.feed(
 		channel,
 		decimator_out.sampling_rate * channel_filter_taps.pass_frequency_normalized,
 		decimator_out.sampling_rate * channel_filter_taps.stop_frequency_normalized

firmware/baseband/proc_am_audio.hpp

@@ -31,6 +31,8 @@
 #include "dsp_iir.hpp"
 #include "dsp_iir_config.hpp"
 
+#include "spectrum_collector.hpp"
+
 class NarrowbandAMAudio : public BasebandProcessor {
 public:
 	NarrowbandAMAudio() {
@@ -40,12 +42,16 @@ public:
 
 	void execute(const buffer_c8_t& buffer) override;
 
+	void on_update_spectrum() override { channel_spectrum.update(); }
+
 private:
 	ChannelDecimator decimator;
 	const fir_taps_real<64>& channel_filter_taps = taps_64_lp_031_070_tfilter;
 	dsp::decimate::FIRAndDecimateComplex channel_filter;
 	dsp::demodulate::AM demod;
 	IIRBiquadFilter audio_hpf { audio_hpf_config };
+
+	SpectrumCollector channel_spectrum;
 };
 
 #endif/*__PROC_AM_AUDIO_H__*/

firmware/baseband/proc_nfm_audio.cpp

@@ -41,7 +41,7 @@ void NarrowbandFMAudio::execute(const buffer_c8_t& buffer) {
 
 	// TODO: Feed channel_stats post-decimation data?
 	feed_channel_stats(channel);
-	feed_channel_spectrum(
+	channel_spectrum.feed(
 		channel,
 		decimator_out.sampling_rate * channel_filter_taps.pass_frequency_normalized,
 		decimator_out.sampling_rate * channel_filter_taps.stop_frequency_normalized

firmware/baseband/proc_nfm_audio.hpp

@@ -32,6 +32,8 @@
 #include "dsp_iir_config.hpp"
 #include "dsp_squelch.hpp"
 
+#include "spectrum_collector.hpp"
+
 class NarrowbandFMAudio : public BasebandProcessor {
 public:
 	NarrowbandFMAudio() {
@@ -41,6 +43,8 @@ public:
 
 	void execute(const buffer_c8_t& buffer) override;
 
+	void on_update_spectrum() override { channel_spectrum.update(); }
+
 private:
 	ChannelDecimator decimator;
 	const fir_taps_real<64>& channel_filter_taps = taps_64_lp_042_078_tfilter;
@@ -49,6 +53,8 @@ private:
 
 	IIRBiquadFilter audio_hpf { audio_hpf_config };
 	FMSquelch squelch;
+
+	SpectrumCollector channel_spectrum;
 };
 
 #endif/*__PROC_NFM_AUDIO_H__*/

firmware/baseband/proc_wideband_spectrum.cpp

@@ -43,24 +43,24 @@ void WidebandSpectrum::execute(const buffer_c8_t& buffer) {
 		std::fill(spectrum.begin(), spectrum.end(), 0);
 	}
 
-	if( (phase & 7) == 0 ) {
+	for(size_t i=0; i<spectrum.size(); i++) {
 		// TODO: Removed window-presum windowing, due to lack of available code RAM.
 		// TODO: Apply window to improve spectrum bin sidelobes.
-		for(size_t i=0; i<channel_spectrum.size(); i++) {
-			spectrum[i] += buffer.p[i];
-		}
+		spectrum[i] += buffer.p[i +    0];
+		spectrum[i] += buffer.p[i + 1024];
 	}
 
-	if( phase == 23 ) {
-		if( channel_spectrum_request_update == false ) {
-			fft_swap(spectrum, channel_spectrum);
-			channel_spectrum_sampling_rate = buffer.sampling_rate;
-			channel_filter_pass_frequency = 0;
-			channel_filter_stop_frequency = 0;
-			channel_spectrum_request_update = true;
-			events_flag(EVT_MASK_SPECTRUM);
+	if( phase == 127 ) {
+		const buffer_c16_t buffer_c16 {
+			spectrum.data(),
+			spectrum.size(),
+			buffer.sampling_rate
+		};
+		channel_spectrum.feed(
+			buffer_c16,
+			0, 0
+		);
 		phase = 0;
-		}
 	} else {
 		phase++;
 	}

firmware/baseband/proc_wideband_spectrum.hpp

@@ -23,6 +23,7 @@
 #define __PROC_WIDEBAND_SPECTRUM_H__
 
 #include "baseband_processor.hpp"
+#include "spectrum_collector.hpp"
 
 #include <cstddef>
 #include <array>
@@ -32,10 +33,14 @@ class WidebandSpectrum : public BasebandProcessor {
 public:
 	void execute(const buffer_c8_t& buffer) override;
 
+	void on_update_spectrum() override { channel_spectrum.update(); }
+
 private:
 	size_t sample_count = 0;
 
-	std::array<std::complex<float>, 256> spectrum;
+	SpectrumCollector channel_spectrum { 1 };
+
+	std::array<complex16_t, 256> spectrum;
 };
 
 #endif/*__PROC_WIDEBAND_SPECTRUM_H__*/

firmware/baseband/spectrum_collector.cpp

@@ -0,0 +1,79 @@
+/*
+ * 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 "spectrum_collector.hpp"
+
+#include "dsp_fft.hpp"
+
+#include "utility.hpp"
+#include "event_m4.hpp"
+#include "portapack_shared_memory.hpp"
+
+#include <algorithm>
+
+void SpectrumCollector::update() {
+	// Called from idle thread (after EVT_MASK_SPECTRUM is flagged)
+	if( channel_spectrum_request_update ) {
+		/* Decimated buffer is full. Compute spectrum. */
+		channel_spectrum_request_update = false;
+		fft_c_preswapped(channel_spectrum);
+
+		ChannelSpectrumMessage spectrum_message;
+		for(size_t i=0; i<spectrum_message.spectrum.db.size(); i++) {
+			const auto mag2 = magnitude_squared(channel_spectrum[i]);
+			const float db = complex16_mag_squared_to_dbv_norm(mag2);
+			constexpr float mag_scale = 5.0f;
+			const unsigned int v = (db * mag_scale) + 255.0f;
+			spectrum_message.spectrum.db[i] = std::max(0U, std::min(255U, v));
+		}
+
+		/* TODO: Rename .db -> .magnitude, or something more (less!) accurate. */
+		spectrum_message.spectrum.db_count = spectrum_message.spectrum.db.size();
+		spectrum_message.spectrum.sampling_rate = channel_spectrum_sampling_rate;
+		spectrum_message.spectrum.channel_filter_pass_frequency = channel_filter_pass_frequency;
+		spectrum_message.spectrum.channel_filter_stop_frequency = channel_filter_stop_frequency;
+		shared_memory.application_queue.push(spectrum_message);
+	}
+}
+
+void SpectrumCollector::feed(
+	const buffer_c16_t& channel,
+	const uint32_t filter_pass_frequency,
+	const uint32_t filter_stop_frequency
+) {
+	channel_filter_pass_frequency = filter_pass_frequency;
+	channel_filter_stop_frequency = filter_stop_frequency;
+	channel_spectrum_decimator.feed(
+		channel,
+		[this](const buffer_c16_t& data) {
+			this->post_message(data);
+		}
+	);
+}
+
+void SpectrumCollector::post_message(const buffer_c16_t& data) {
+	if( !channel_spectrum_request_update ) {
+		fft_swap(data, channel_spectrum);
+		channel_spectrum_sampling_rate = data.sampling_rate;
+		channel_spectrum_request_update = true;
+		events_flag(EVT_MASK_SPECTRUM);
+	}
+}

firmware/baseband/spectrum_collector.hpp

@@ -0,0 +1,61 @@
+/*
+ * 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 __SPECTRUM_COLLECTOR_H__
+#define __SPECTRUM_COLLECTOR_H__
+
+#include "dsp_types.hpp"
+#include "complex.hpp"
+
+#include "block_decimator.hpp"
+
+#include <cstdint>
+#include <array>
+
+class SpectrumCollector {
+public:
+	constexpr SpectrumCollector(
+		const size_t decimation_factor = 4
+	) : channel_spectrum_decimator { decimation_factor }
+	{
+	}
+
+	void update();
+
+	void feed(
+		const buffer_c16_t& channel,
+		const uint32_t filter_pass_frequency,
+		const uint32_t filter_stop_frequency
+	);
+
+private:
+	BlockDecimator<256> channel_spectrum_decimator;
+
+	volatile bool channel_spectrum_request_update { false };
+	std::array<std::complex<float>, 256> channel_spectrum;
+	uint32_t channel_spectrum_sampling_rate { 0 };
+	uint32_t channel_filter_pass_frequency { 0 };
+	uint32_t channel_filter_stop_frequency { 0 };
+
+	void post_message(const buffer_c16_t& data);
+};
+
+#endif/*__SPECTRUM_COLLECTOR_H__*/

firmware/common/complex.hpp

@@ -101,6 +101,13 @@ public:
 	void real(int16_t v) { _v[0] = v; }
 	void imag(int16_t v) { _v[1] = v; }
 
+	template<class X>
+	complex<int16_t>& operator+=(const complex<X>& other) {
+		_v[0] += other.real();
+		_v[1] += other.imag();
+		return *this;
+	}
+
 	constexpr uint32_t __rep() const {
 		return _rep;
 	}