Improved POCSAG receiver reliability

firmware/application/CMakeLists.txt

@@ -196,6 +196,7 @@ set(CPPSRC
 	${COMMON}/ais_baseband.cpp
 	${COMMON}/ais_packet.cpp
 	${COMMON}/pocsag_packet.cpp
+	${COMMON}/pocsag.cpp
 	ais_app.cpp
 	tpms_app.cpp
 	pocsag_app.cpp
@@ -298,6 +299,7 @@ set(CPPWARN "-Wall -Wextra")
 # List all default C defines here, like -D_DEBUG=1
 # TODO: Switch -DCRT0_INIT_DATA depending on load from RAM or SPIFI?
 # NOTE: _RANDOM_TCC to kill a GCC 4.9.3 error with std::max argument types
+
 set(DDEFS -DLPC43XX -DLPC43XX_M0 -D__NEWLIB__ -DHACKRF_ONE -DTOOLCHAIN_GCC -DTOOLCHAIN_GCC_ARM -D_RANDOM_TCC=0 -DGIT_REVISION=\"${GIT_REVISION}\")
 
 # List all default ASM defines here, like -D_DEBUG=1

firmware/application/Makefile

@@ -2516,6 +2516,33 @@ __/common/png_writer.cpp.s:
 	cd /home/furrtek/portapack-hackrf && $(MAKE) -f firmware/application/CMakeFiles/application.elf.dir/build.make firmware/application/CMakeFiles/application.elf.dir/__/common/png_writer.cpp.s
 .PHONY : __/common/png_writer.cpp.s
 
+__/common/pocsag.obj: __/common/pocsag.cpp.obj
+
+.PHONY : __/common/pocsag.obj
+
+# target to build an object file
+__/common/pocsag.cpp.obj:
+	cd /home/furrtek/portapack-hackrf && $(MAKE) -f firmware/application/CMakeFiles/application.elf.dir/build.make firmware/application/CMakeFiles/application.elf.dir/__/common/pocsag.cpp.obj
+.PHONY : __/common/pocsag.cpp.obj
+
+__/common/pocsag.i: __/common/pocsag.cpp.i
+
+.PHONY : __/common/pocsag.i
+
+# target to preprocess a source file
+__/common/pocsag.cpp.i:
+	cd /home/furrtek/portapack-hackrf && $(MAKE) -f firmware/application/CMakeFiles/application.elf.dir/build.make firmware/application/CMakeFiles/application.elf.dir/__/common/pocsag.cpp.i
+.PHONY : __/common/pocsag.cpp.i
+
+__/common/pocsag.s: __/common/pocsag.cpp.s
+
+.PHONY : __/common/pocsag.s
+
+# target to generate assembly for a file
+__/common/pocsag.cpp.s:
+	cd /home/furrtek/portapack-hackrf && $(MAKE) -f firmware/application/CMakeFiles/application.elf.dir/build.make firmware/application/CMakeFiles/application.elf.dir/__/common/pocsag.cpp.s
+.PHONY : __/common/pocsag.cpp.s
+
 __/common/pocsag_packet.obj: __/common/pocsag_packet.cpp.obj
 
 .PHONY : __/common/pocsag_packet.obj
@@ -5571,6 +5598,9 @@ help:
 	@echo "... __/common/png_writer.obj"
 	@echo "... __/common/png_writer.i"
 	@echo "... __/common/png_writer.s"
+	@echo "... __/common/pocsag.obj"
+	@echo "... __/common/pocsag.i"
+	@echo "... __/common/pocsag.s"
 	@echo "... __/common/pocsag_packet.obj"
 	@echo "... __/common/pocsag_packet.i"
 	@echo "... __/common/pocsag_packet.s"

firmware/application/main.cpp

@@ -24,7 +24,7 @@
 // Gimp image > indexed colors (16), then "xxd -i *.bmp"
 
 //BUG: (fixed ?) POCSAG: Bad console scroll init
-//BUG: POCSAG misses alphanum messages, cuts them off sometimes
+//BUG: (fixed ?) POCSAG misses alphanum messages, cuts them off sometimes
 //BUG: Check AFSK transmit end, skips last bits ?
 //BUG: RDS doesn't stop baseband when stopping tx ?
 

firmware/application/pocsag_app.cpp

@@ -24,46 +24,19 @@
 
 #include "baseband_api.hpp"
 
+#include "audio.hpp"
 #include "portapack.hpp"
 #include "portapack_persistent_memory.hpp"
 using namespace portapack;
+using namespace pocsag;
 
+#include "pocsag.hpp"
 #include "string_format.hpp"
 
 #include "utility.hpp"
 
-#define POCSAG_SYNC     0x7CD215D8
-#define POCSAG_IDLE		0x7A89C197
-
-namespace pocsag {
-
-namespace format {
-
-static std::string bitrate_str(BitRate bitrate) {
-	switch (bitrate) {
-		case BitRate::FSK512:	return "512 ";
-		case BitRate::FSK1200:	return "1200";
-		case BitRate::FSK2400:	return "2400";
-		default:				return "????";
-	}
-}
-
-static std::string flag_str(PacketFlag packetflag) {
-	switch (packetflag) {
-		case PacketFlag::NORMAL:	return "OK";
-		case PacketFlag::IDLE:		return "IDLE";
-		case PacketFlag::TIMED_OUT:	return "TIMED OUT";
-		case PacketFlag::TOO_LONG:	return "TOO LONG";
-		default:					return "";
-	}
-}
-
-} /* namespace format */
-
-} /* namespace pocsag */
-
 void POCSAGLogger::on_packet(const pocsag::POCSAGPacket& packet, const uint32_t frequency) {
-	std::string entry = pocsag::format::bitrate_str(packet.bitrate()) + " " + to_string_dec_uint(frequency) + "Hz ";
+	std::string entry = pocsag::bitrate_str(packet.bitrate()) + " " + to_string_dec_uint(frequency) + "Hz ";
 	
 	// Raw hex dump of all the codewords
 	for (size_t c = 0; c < 16; c++)
@@ -118,16 +91,6 @@ POCSAGAppView::POCSAGAppView(NavigationView& nav) {
 		&console
 	});
 	
-	radio::enable({
-		tuning_frequency(),
-		sampling_rate,
-		baseband_bandwidth,
-		rf::Direction::Receive,
-		receiver_model.rf_amp(),
-		static_cast<int8_t>(receiver_model.lna()),
-		static_cast<int8_t>(receiver_model.vga())
-	});
-	
 	check_log.set_value(logging);
 	check_log.on_select = [this](Checkbox&, bool v) {
 		logging = v;
@@ -153,11 +116,20 @@ POCSAGAppView::POCSAGAppView(NavigationView& nav) {
 	logger = std::make_unique<POCSAGLogger>();
 	if (logger) logger->append("pocsag.txt");
 	
+	receiver_model.set_sampling_rate(3072000);
+	receiver_model.set_baseband_bandwidth(1750000);
+	receiver_model.enable();
+	
+	const auto new_volume = volume_t::decibel(60 - 99) + audio::headphone::volume_range().max;
+	receiver_model.set_headphone_volume(new_volume);
+	audio::output::start();
+	
 	baseband::set_pocsag(pocsag::BitRate::FSK1200);
 }
 
 POCSAGAppView::~POCSAGAppView() {
-	radio::disable();
+	audio::output::stop();
+	receiver_model.disable();
 	baseband::shutdown();
 }
 
@@ -165,89 +137,63 @@ void POCSAGAppView::focus() {
 	options_freq.focus();
 }
 
+// Useless ?
 void POCSAGAppView::set_parent_rect(const Rect new_parent_rect) {
 	View::set_parent_rect(new_parent_rect);
 }
 
 void POCSAGAppView::on_packet(const POCSAGPacketMessage * message) {
-	bool eom = false;
-	uint32_t codeword;
 	std::string alphanum_text = "";
-	char ascii_char;
-	
-	for (size_t i = 0; i < 16; i++) {
-		codeword = message->packet[i];
-		
-		if (codeword & 0x80000000U) {
-			// Message
-			ascii_data |= ((codeword >> 11) & 0xFFFFF);
-			ascii_idx += 20;
-			
-			// Raw 20 bits to 7 bit reversed ASCII
-			while (ascii_idx >= 7) {
-				ascii_idx -= 7;
-				ascii_char = (ascii_data >> ascii_idx) & 0x7F;
-				
-				// Bottom's up
-				ascii_char = (ascii_char & 0xF0) >> 4 | (ascii_char & 0x0F) << 4;	// 01234567 -> 45670123
-				ascii_char = (ascii_char & 0xCC) >> 2 | (ascii_char & 0x33) << 2;	// 45670123 -> 67452301
-				ascii_char = (ascii_char & 0xAA) >> 2 | (ascii_char & 0x55);		// 67452301 -> *7654321
-   
-				// Translate non-printable chars
-				if ((ascii_char < 32) || (ascii_char > 126))
-					output_text += "[" + to_string_dec_uint(ascii_char) + "]";
-				else
-					output_text += ascii_char;
-
-			}
-			ascii_data = ascii_data << 20;
-		} else {
-			// Address
-			if ((codeword == POCSAG_IDLE) || (codeword == POCSAG_SYNC)) {
-				eom = true;
-			} else {
-				if ((codeword) && (!address)) {
-					// Set address if none set and codeword is valid
-					function = (codeword >> 11) & 3;
-					address = ((codeword >> 10) & 0x1FFFF8) | ((codeword >> 1) & 7);
-				}
-			}
-		}
-	}
 	
+	// Log raw data
 	if (logger && logging) logger->on_packet(message->packet, target_frequency());
 	
-	if (eom) {
-		std::string console_info;
-		
-		console_info = to_string_time(message->packet.timestamp()) + " ";
-		
-		if (address || function) {
-			console_info += pocsag::format::bitrate_str( message->packet.bitrate()) + " ";
-			console_info += pocsag::format::flag_str(message->packet.flag()) + " ";
-			console_info += "ADDR:" + to_string_dec_uint(address) + " F:" + to_string_dec_uint(function);
-			
-			console.writeln(console_info);
-			
-			if (output_text != "") console.writeln("Alpha:" + output_text);
-			
-			if (logger) logger->on_decoded(message->packet, console_info, output_text);
-			
-		} else {
-			console_info += pocsag::format::bitrate_str(message->packet.bitrate()) + " ";
-			console_info += pocsag::format::flag_str(message->packet.flag());
-			
-			console.writeln(console_info);
+	if (message->packet.flag() != NORMAL) {
+		console.writeln(
+			"RX ERROR: " + pocsag::flag_str(message->packet.flag()) +
+			" Codewords: " + to_string_dec_uint(message->packet[0])
+		);
 	}
 	
-		output_text = "";
-		ascii_idx = 0;
-		ascii_data = 0;
-		batch_cnt = 0;
-		address = 0;
-		function = 0;
+	bool result = decode_batch(message->packet, &pocsag_state);
+
+	if (result) {
+		std::string console_info;
+		
+		if (pocsag_state.out_type == ADDRESS) {
+			// Address only
+			console_info = to_string_time(message->packet.timestamp()) + " ";
+			console_info += pocsag::bitrate_str(message->packet.bitrate()) + " ";
+			console_info += "ADDR:" + to_string_dec_uint(pocsag_state.address);
+			console_info += " F" + to_string_dec_uint(pocsag_state.function);
+			
+			console.writeln(console_info);
+			
+			if (logger) logger->on_decoded(message->packet, console_info, pocsag_state.output);
+			
+			last_address = pocsag_state.address;
+		} else if (pocsag_state.out_type == MESSAGE) {
+			if (pocsag_state.address != last_address) {
+				// New message
+				console_info = to_string_time(message->packet.timestamp()) + " ";
+				console_info += pocsag::bitrate_str( message->packet.bitrate()) + " ";
+				console_info += "ADDR:" + to_string_dec_uint(pocsag_state.address);
+				console_info += " F" + to_string_dec_uint(pocsag_state.function);
+				
+				console.writeln(console_info);
+				
+				console.writeln("Alpha:" + pocsag_state.output);
+				
+				if (logger) logger->on_decoded(message->packet, console_info, pocsag_state.output);
+				
+				last_address = pocsag_state.address;
 			} else {
-		batch_cnt++;
+				// Message continues...
+			}
+		} else if (pocsag_state.out_type == EMPTY)
+			console.writeln("-");
+		
+		console.write(pocsag_state.output);
 	}
 }
 
@@ -267,15 +213,11 @@ void POCSAGAppView::on_band_changed(const uint32_t new_band_frequency) {
 
 void POCSAGAppView::set_target_frequency(const uint32_t new_value) {
 	target_frequency_ = new_value;
-	radio::set_tuning_frequency(tuning_frequency());
+	receiver_model.set_tuning_frequency(new_value);
 }
 
 uint32_t POCSAGAppView::target_frequency() const {
 	return target_frequency_;
 }
 
-uint32_t POCSAGAppView::tuning_frequency() const {
-	return target_frequency() - (sampling_rate / 4);
-}
-
 } /* namespace ui */

firmware/application/pocsag_app.hpp

@@ -33,6 +33,7 @@
 
 #include "log_file.hpp"
 
+#include "pocsag.hpp"
 #include "pocsag_packet.hpp"
 
 class POCSAGLogger {
@@ -66,15 +67,11 @@ public:
 private:
 	static constexpr uint32_t initial_target_frequency = 466175000;
 	static constexpr uint32_t sampling_rate = 3072000;
-	static constexpr uint32_t baseband_bandwidth = 1750000;
+	//static constexpr uint32_t baseband_bandwidth = 1750000;
 
 	bool logging { false };
-	uint32_t batch_cnt = 0;
-	uint32_t address { 0 };
-	uint32_t function { 0 };
-	uint32_t ascii_data { 0 };
-	uint32_t ascii_idx { 0 };
-	std::string output_text = "";
+	uint32_t last_address = 0xFFFFFFFF;
+	pocsag::POCSAGState pocsag_state { };
 	
 	MessageHandlerRegistration message_handler_packet {
 		Message::ID::POCSAGPacket,
@@ -158,8 +155,6 @@ private:
 
 	uint32_t target_frequency() const;
 	void set_target_frequency(const uint32_t new_value);
-
-	uint32_t tuning_frequency() const;
 };
 
 } /* namespace ui */

firmware/baseband/proc_nfm_audio.cpp

@@ -22,8 +22,6 @@
 
 #include "proc_nfm_audio.hpp"
 
-#include "audio_output.hpp"
-
 #include "event_m4.hpp"
 
 #include <cstdint>

firmware/baseband/proc_pocsag.cpp

@@ -29,13 +29,6 @@
 #include <cstdint>
 #include <cstddef>
 
-#define POCSAG_AUDIO_RATE		24000
-
-#define POCSAG_SYNC		0x7CD215D8
-#define POCSAG_IDLE		0x7A89C197
-#define POCSAG_PREAMBLE_LENGTH	576
-#define POCSAG_BATCH_LENGTH		(9 * 32)
-
 void POCSAGProcessor::execute(const buffer_c8_t& buffer) {
 	// This is called at 1500Hz
 	
@@ -46,12 +39,11 @@ void POCSAGProcessor::execute(const buffer_c8_t& buffer) {
 	const auto decim_1_out = decim_1.execute(decim_0_out, dst_buffer);
 	const auto channel_out = channel_filter.execute(decim_1_out, dst_buffer);
 	auto audio = demod.execute(channel_out, audio_buffer);
+	//audio_output.write(audio);
 	
-	// End up with 32 samples ?
 	for (uint32_t c = 0; c < 16; c++) {
 		
 		const int32_t sample_int = audio.p[c] * 32768.0f;
-		//const int32_t audio_sample = audio.p[c] * 32768.0f;
 		const int32_t audio_sample = __SSAT(sample_int, 16);
 		
 		slicer_sr <<= 1;
@@ -84,23 +76,22 @@ void POCSAGProcessor::execute(const buffer_c8_t& buffer) {
 					break;
 				
 				case PREAMBLE:
-					if (sync_timeout < POCSAG_PREAMBLE_LENGTH) {
+					if (sync_timeout < POCSAG_TIMEOUT) {
 						sync_timeout++;
 
 						if (rx_data == POCSAG_SYNC) {
 							packet.clear();
-							frame_counter = 0;
+							codeword_count = 0;
 							rx_bit = 0;
 							msg_timeout = 0;
-							last_rx_data = rx_data;
 							rx_state = SYNC;
-						} else if (rx_data == POCSAG_IDLE) {
-							push_packet(pocsag::PacketFlag::IDLE);
+						} /*else if (rx_data == POCSAG_IDLE) {
 							rx_state = WAITING;
-						}
+						}*/
 						
 					} else {
 						rx_state = WAITING;		// Timed out: abort
+						push_packet(pocsag::PacketFlag::TOO_LONG);	// DEBUG
 					}
 					break;
 				
@@ -116,29 +107,18 @@ void POCSAGProcessor::execute(const buffer_c8_t& buffer) {
 							
 							//pocsag_brute_repair(&s->l2.pocsag, &rx_data);
 							
-							packet.set(frame_counter, rx_data);
+							packet.set(codeword_count, rx_data);
 							
-							if ((rx_data == POCSAG_IDLE) && (!(last_rx_data & 0x80000000))) {
-								// SYNC then IDLE always means end of message ?
-								if (frame_counter)
+							if (codeword_count < 15) {
+								codeword_count++;
+							} else {
 								push_packet(pocsag::PacketFlag::NORMAL);
-								else
-									push_packet(pocsag::PacketFlag::IDLE);
-								rx_state = WAITING;
-							} else {
-								if (frame_counter < 15) {
-									frame_counter++;
-								} else {
-									// More than 17-1 codewords
-									push_packet(pocsag::PacketFlag::TOO_LONG);
 								rx_state = WAITING;
 							}
 						}
-							
-							last_rx_data = rx_data;
-						}
 					} else {
 						// Timed out (no end of message received)
+						packet.set(0, codeword_count);	// DEBUG
 						push_packet(pocsag::PacketFlag::TIMED_OUT);
 						rx_state = WAITING;
 					}
@@ -180,6 +160,7 @@ void POCSAGProcessor::configure(const POCSAGConfigureMessage& message) {
 	decim_1.configure(taps_11k0_decim_1.taps, 131072);
 	channel_filter.configure(taps_11k0_channel.taps, 2);
 	demod.configure(demod_input_fs, 4500);
+	//audio_output.configure(false);
 
 	bitrate = message.bitrate;
 	sphase_delta = 0x10000u * bitrate / POCSAG_AUDIO_RATE;

firmware/baseband/proc_pocsag.hpp

@@ -34,7 +34,9 @@
 
 #include "pocsag_packet.hpp"
 
+#include "pocsag.hpp"
 #include "message.hpp"
+#include "audio_output.hpp"
 #include "portapack_shared_memory.hpp"
 
 #include <cstdint>
@@ -78,6 +80,8 @@ private:
 	dsp::decimate::FIRAndDecimateComplex channel_filter { };
 	dsp::demodulate::FM demod { };
 	
+	//AudioOutput audio_output { };
+
 	uint32_t sync_timeout { 0 };
 	uint32_t msg_timeout { 0 };
 
@@ -87,12 +91,11 @@ private:
 	uint32_t sphase_delta_half { 0 };
 	uint32_t sphase_delta_eighth { 0 };
 	uint32_t rx_data { 0 };
-	uint32_t last_rx_data { 0 };
 	uint32_t rx_bit { 0 };
 	bool configured = false;
 	rx_states rx_state { WAITING };
 	pocsag::BitRate bitrate { pocsag::BitRate::FSK1200 };
-	uint32_t frame_counter { 0 };
+	uint32_t codeword_count { 0 };
 	pocsag::POCSAGPacket packet { };
 	
 	void push_packet(pocsag::PacketFlag flag);

firmware/common/pocsag.cpp

@@ -0,0 +1,124 @@
+/*
+ * Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
+ * Copyright (C) 2016 Furrtek
+ *
+ * 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 "pocsag.hpp"
+
+#include "baseband_api.hpp"
+
+#include "portapack.hpp"
+#include "portapack_persistent_memory.hpp"
+using namespace portapack;
+
+#include "string_format.hpp"
+
+#include "utility.hpp"
+
+namespace pocsag {
+
+std::string bitrate_str(BitRate bitrate) {
+	switch (bitrate) {
+		case BitRate::FSK512:	return "512 ";
+		case BitRate::FSK1200:	return "1200";
+		case BitRate::FSK2400:	return "2400";
+		default:				return "????";
+	}
+}
+
+std::string flag_str(PacketFlag packetflag) {
+	switch (packetflag) {
+		case PacketFlag::NORMAL:	return "OK";
+		case PacketFlag::IDLE:		return "IDLE";
+		case PacketFlag::TIMED_OUT:	return "TIMED OUT";
+		case PacketFlag::TOO_LONG:	return "TOO LONG";
+		default:					return "";
+	}
+}
+
+bool decode_batch(const POCSAGPacket& batch, POCSAGState * const state) {
+	uint32_t codeword;
+	char ascii_char;
+	std::string output_text = "";
+	
+	state->out_type = EMPTY;
+	
+	// For each codeword...
+	for (size_t i = 0; i < 16; i++) {
+		codeword = batch[i];
+		
+		if (!(codeword & 0x80000000U)) {
+			// Address codeword
+			if (state->mode == STATE_CLEAR) {
+				if (codeword != POCSAG_IDLE) {
+					state->function = (codeword >> 11) & 3;
+					state->address = (codeword >> 10) & 0x1FFFF8U;	// 18 MSBs are transmitted
+					state->mode = STATE_HAVE_ADDRESS;
+					state->out_type = ADDRESS;
+					
+					state->ascii_idx = 0;
+					state->ascii_data = 0;
+				}
+			} else {
+				state->mode = STATE_CLEAR;				// New address = new message
+			}
+		} else {
+			// Message codeword
+			if (state->mode == STATE_HAVE_ADDRESS) {
+				// First message codeword: complete address
+				state->address |= (i >> 1);				// Add in the 3 LSBs (frame #)
+				state->mode = STATE_GETTING_MSG;
+			}
+			
+			state->out_type = MESSAGE;
+			
+			state->ascii_data |= ((codeword >> 11) & 0xFFFFF);	// Get 20 message bits
+			state->ascii_idx += 20;
+			
+			// Raw 20 bits to 7 bit reversed ASCII
+			while (state->ascii_idx >= 7) {
+				state->ascii_idx -= 7;
+				ascii_char = ((state->ascii_data) >> (state->ascii_idx)) & 0x7F;
+				
+				// Bottom's up
+				ascii_char = (ascii_char & 0xF0) >> 4 | (ascii_char & 0x0F) << 4;	// 01234567 -> 45670123
+				ascii_char = (ascii_char & 0xCC) >> 2 | (ascii_char & 0x33) << 2;	// 45670123 -> 67452301
+				ascii_char = (ascii_char & 0xAA) >> 2 | (ascii_char & 0x55);		// 67452301 -> *7654321
+   
+				// Translate non-printable chars
+				if ((ascii_char < 32) || (ascii_char > 126))
+					output_text += "[" + to_string_dec_uint(ascii_char) + "]";
+				else
+					output_text += ascii_char;
+			}
+			
+			state->ascii_data <<= 20;		// Remaining bits are for next time...
+		}
+	}
+	
+	state->output = output_text;
+	
+	if (state->mode == STATE_HAVE_ADDRESS)
+		state->mode = STATE_CLEAR;
+	
+	return true;
+}
+
+} /* namespace pocsag */

firmware/common/pocsag.hpp

@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
+ * Copyright (C) 2016 Furrtek
+ *
+ * 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 __POCSAG_H__
+#define __POCSAG_H__
+
+#define POCSAG_TIMEOUT (576 * 2)	// Preamble length * 2
+#define POCSAG_SYNC 0x7CD215D8
+#define POCSAG_IDLE 0x7A89C197
+#define POCSAG_AUDIO_RATE 24000
+#define POCSAG_BATCH_LENGTH (17 * 32)
+
+#include "pocsag_packet.hpp"
+
+namespace pocsag {
+
+enum Mode : uint32_t {
+	STATE_CLEAR,
+	STATE_HAVE_ADDRESS,
+	STATE_GETTING_MSG
+};
+
+enum OutputType : uint32_t {
+	EMPTY,
+	ADDRESS,
+	MESSAGE
+};
+
+struct POCSAGState {
+	uint32_t function;
+	uint32_t address;
+	Mode mode = STATE_CLEAR;
+	OutputType out_type = EMPTY;
+	uint32_t ascii_data;
+	uint32_t ascii_idx;
+	std::string output;
+};
+
+std::string bitrate_str(BitRate bitrate);
+std::string flag_str(PacketFlag packetflag);
+
+bool decode_batch(const POCSAGPacket& batch, POCSAGState * const state);
+
+} /* namespace pocsag */
+
+#endif/*__POCSAG_H__*/