d17d683b2d
M17 code cleanup pass: reorganised data type definitions and constants
2022-05-27 21:49:33 +02:00
7aff678069
Improved robustness of frame type detection, now based on minimum hamming distance between syncwords
2022-05-27 21:49:33 +02:00
c987848382
Add syncword hot re-sync fix DC removal
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DC removal filter had a bug that created weird positive spikes on
Module17, add a syncword hot re-sync to be able to correct small phase
errors that appear every five seconds more or less.
TG-81
2022-05-27 21:48:47 +02:00
1f77c2af6c
Reorganised logging inside M17 demodulator, logging is disabled by default.
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On non-linux devices log data is printed on the serial port in raw binary format.
2022-05-27 21:48:47 +02:00
ef61c532a3
Cleaned up quantization average
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Now average is computed over all the syncword symbols, for each syncword
as a simple average.
TG-81
2022-05-27 21:48:47 +02:00
5fe5b0e578
Refactor M17 logging
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Refactored logging functions to enable in-system logging on Module17 and
MDx radios.
TG-81
2022-05-27 21:48:47 +02:00
361308be16
Generator of pseudorandom binary sequence compliant with M17 specification
2022-05-27 21:48:47 +02:00
3988540b6c
Changed coefficients for the 41-tap, 24kHz RRC filter to have unitary input-output gain
2022-05-27 21:48:47 +02:00
c3c984d504
Add syncword fuzzy detection
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Frame decoder now tolerates bit error in syncword, removed syncword type
detection in demodulator code.
TG-81
2022-05-27 21:48:47 +02:00
6b31a73f42
Corrected RRC gain and changed HR_C5000 modulation factor and input gain to have the correct 2.4kHz deviation when transmitting M17 with an MD3x0 radio
2022-05-27 21:48:47 +02:00
2d59658d60
Switch M17 Rx sample rate to 5SPS
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Due to the RRC computation sometimes violating the timing constraints,
we switched the M17 demodulator to 5 samples per symbol (24KHz), thus
dividing the processing time by four ar the number of samples halves as
well as the number of taps of the RRC.
Minor adaptation on the code followed.
TG-81
2022-05-27 21:48:47 +02:00
63bd864674
Fix M17 Rx LED
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Now LED turns on when a syncword is successfully detected, not just when
the correlation is sufficiently high.
TG-81
2022-05-27 21:48:47 +02:00
c4483edff0
Improve quantization strategy
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Now quantization is performed by averaging syncword samples and dividing
the resulting threshold by a constant.
TG-81
2022-05-27 21:48:47 +02:00
7d1b89550e
Rewrite quantization algorithm
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Quantization algorithm is now based on separate rolling averages for
positive and negative samples.
Merged csv outputs from syncword search and quantization on Linux.
TG-81
2022-05-27 21:48:47 +02:00
aa9fcc26b7
Remove useless DC bias in quantization
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TG-81
2022-05-27 21:48:47 +02:00
d1651a702c
Add proper DC-bias removal, tuned EMAs
2022-05-27 21:48:47 +02:00
da5c453852
Implemented unpacking and decoding of M17 audio stream frames
2022-05-27 21:48:47 +02:00
beca0d2acc
Reorganised constants inside M17 demodulator class
2022-05-27 21:48:47 +02:00
fda0fed5e7
Moved constant specifying sample rate for M17 baseband decoding from hwconfig.h files to M17Demodulator class
2022-05-27 21:48:47 +02:00
e5b5daba85
Moved state variables of PWM compensator and DC removal filter outside the function bodies to allow keeping their consistency among function calls
2022-05-27 21:48:47 +02:00
4b8685b853
Changed gain and added an offset at tx RRC stage only for Module 17 to compensate for an hardware bug
2022-05-27 21:48:47 +02:00
d1b4973cc9
Fixed reset of DC bias on stream stop in Module 17 output stream driver, made parametric the gain of the RRC at modulator side
2022-05-27 21:48:47 +02:00
54a89abcd0
Removed a printf left behind after debugging from M17 demodulator class and slightly cleaned up the code
2022-05-27 21:48:47 +02:00
c9a4bfb199
Cleanup and refactoring of M17 modulator class, now using output streams for baseband signal output
2022-05-27 21:48:47 +02:00
427c5f50b3
Made M17Demodulator::update() return a boolean indicating when a new decoded frame is ready
2022-05-27 21:48:47 +02:00
77aead675a
Improve runtime performance of M17 Demodulator
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Tweaked the exponential moving average alpha factors to improve the
reactivity of the M17 demodulator.
TG-81
2022-05-27 21:48:47 +02:00
5ef145cd39
Add fuzzy syncword validation
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Now syncword match is not exact but can tolerate up to two erroneous
bits.
TG-81
2022-05-27 21:48:47 +02:00
ca49b306b9
Update constants for M17 demodulation
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Constants were updated to increase performance based on baseband sample
collected with Module17.
TG-81
2022-05-27 21:48:47 +02:00
2d8c696a09
Complete M17 demodulator implementation
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Make quantization work also on DC offset signal
Add samples plot code
Fix bug in buffer wrap around
Fix oob memory access in M17 modulator
Update tests with DC offset signal
Switch to 48KHz sample rate for Module17 and MD380
Add DC biasing script
TG-81
2022-05-27 21:48:46 +02:00
ae26cca46f
Remove SPS
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Now M17_SAPLES_PER_SYMBOL is computed dinamically from sample rate.
TG-81
2022-05-27 21:48:46 +02:00
a091bca35f
M17 Demodulator bugfixes
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Fixed several bugs in the M17 Demodulator code.
TG-81
2022-05-27 21:48:46 +02:00
35c1f062c6
Implementation of M17 frame encoder
2022-05-27 21:48:46 +02:00
82dd0a63f1
Clarification of naming: renamed DATA_SYNC_WORD to STREAM_SYNC_WORD and Audio_puncture to DATA_PUNCTURE
2022-05-27 21:48:46 +02:00
5fbd39959c
Implementation of M17 frame decoder
2022-05-27 21:48:46 +02:00
49bd8ee2f4
Reorganised internal structure of M17LinkSetupFrame class, renamed M17Frame to M17StreamFrame and reorganised its structure
2022-05-27 21:48:46 +02:00
c73aa92305
Reorganised M17LinkSetupframe and M17Frame classes, encapsulating structs defining their internal data structure
2022-05-27 21:48:46 +02:00
7a9bbfcaf2
Demodulator bugfix
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Fix several bugs in the demodulator code, tipycally sign errors.
2022-05-27 21:48:46 +02:00
1a9b3c4168
Implement M17 demodulator logic
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Implemented frame wrapping logic and demodulator loop.
2022-05-27 21:48:46 +02:00
963fbdc141
M17 mode handler: calling demodulator update function when in RX mode
2022-05-27 21:48:46 +02:00
5bf4df75ba
Fine tune demodulator to OpenRTX M17 baseband
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Fine tuned M17 demodulator with code generated from OpenRTX itself.
TG-81
2022-05-27 21:48:46 +02:00
4b498689f5
Replace RRC filter taps, update M17 testsuite
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RRC filter taps have been replaced with the ones generated by Wojciech,
a new baseband for the M17 demodulation testsuite has been generated,
using OpenRTX itself and some further minor changes.
TG-81
2022-05-27 21:48:46 +02:00
3163dd49d7
Add M17 demodulator code and tests
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Added implementation of the M17 4FSK demodulator, including clock
recovery, phase detection, and quantization algorithms.
A testsuite is also included to do regression testing against a
reference baseband pre-generated and the corresponding reference
bitstream.
A 1% BER is still present due to a fault likely in the RRC filtering,
since the eye diagram of the filtered stream is bad.
TG-81
2022-05-27 21:48:46 +02:00
396f66a1f3
Implementation of M17 Viterbi decoder and associated unit test
2022-05-27 21:48:46 +02:00
3aeade6c1f
Clarify M17 modulator constant naming
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Further clarify modulator constant naming for sample rate and frame
lengths, to distinguish between demodulator values.
2022-05-27 21:48:46 +02:00
6588a6718e
Add M17 namespace in M17 related source files
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Now M17 source files reside in the M17 namespace, the OPMODE_ prefix
was added to all opmode enums to avoid a name clash.
2022-05-27 21:48:46 +02:00
876cb87d57
Move rrc filter into separate compilation unit
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By moving the rrc filter into a separate compilation unit with its own
header file, we can use it both in the modulator and in the demodulator.
2022-05-27 21:48:46 +02:00
c648ffe377
Add draft of M17Demodulator class
2022-05-27 21:48:46 +02:00
8a3643ad3a
Implementation of Golay(24,12) decoder, reimplemented Golay(24,12) encoder using generator matrix, unit test for Golay(24,12) encoding and decoding routines
2022-05-27 21:48:46 +02:00
a3b7b490d4
Fixed jitter in M17 baseband signal generation
2022-05-27 21:48:46 +02:00
a9e1e68709
Implemented function for inverse code puncturing in M17 protocol
2021-10-03 12:09:00 +02:00
Silvano Seva
Niccolò Izzo