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55 commits

Author SHA1 Message Date
Ahmet Inan
0e6b41a9c5 added comment for debugging 2023-02-16 10:29:51 +01:00
Ahmet Inan
ad1dc32e7f lowered lowest allowed volume by an order of magnitude 2023-02-12 11:10:33 +01:00
Ahmet Inan
13dd3481c7 added 8 bit operation mode symbol 2023-02-11 21:18:14 +01:00
Ahmet Inan
2763a9c2e8 renamed delay to align 2023-02-10 12:32:38 +01:00
Ahmet Inan
1987562651 reduced size of buffering 2023-02-10 11:53:47 +01:00
Ahmet Inan
a9d4249ea5 removed redundant buffers 2023-02-10 11:43:04 +01:00
Ahmet Inan
b1d704513b frequency shifted sync symbol not worth the trouble 2023-02-10 11:28:59 +01:00
Ahmet Inan
cca0199d63 omit guard between synchronization symbols 2023-02-10 11:25:39 +01:00
Ahmet Inan
964c3f0ea3 the distance needs to include the guard now 2023-02-10 10:02:15 +01:00
Ahmet Inan
e57afffecf need to align the rotation 2023-02-10 09:15:52 +01:00
Ahmet Inan
b857741d9d experimenting with a scheme for Ribbit 2023-02-09 23:50:43 +01:00
Ahmet Inan
c9ce52c45c set data_len to zero on payload error 2023-02-03 11:31:13 +01:00
Ahmet Inan
6f58e93018 added support for modes 0, 15 and 16 2023-01-04 15:37:23 +01:00
Ahmet Inan
91ba106dc6 use int8_t for a larger list 2022-05-19 12:21:09 +02:00
Ahmet Inan
41795780cb added mode 14 for short messages 
using SPC(2048, 1392), QPSK, 1600 Hz BW and about 1 second long
 2022-05-18 23:14:26 +02:00
Ahmet Inan
16e495ab9c show number of bit flips 2022-05-18 16:38:41 +02:00
Ahmet Inan
8a9c7f29a2 use precision estimate from each OFDM symbol 2022-05-18 12:29:48 +02:00
Ahmet Inan
44fae606fd simplified precision estimation 2022-05-18 12:05:47 +02:00
Ahmet Inan
0fac5fc62b added prepare() 2021-10-08 11:30:20 +02:00
Ahmet Inan
2c72572e27 Revert "estimate SFO by cross-correlating S&C symbols" 
This reverts commit 96ea292b0c.
 2021-09-17 22:52:53 +02:00
Ahmet Inan
da855f6510 replace "-" with "/dev/stdin" or "/dev/stdout" 2021-09-12 10:15:47 +02:00
Ahmet Inan
96ea292b0c estimate SFO by cross-correlating S&C symbols 2021-09-07 00:19:06 +02:00
Ahmet Inan
56bd51012c show a dot for each symbol demodulated 2021-09-06 16:11:15 +02:00
Ahmet Inan
ba102a5799 added next_sample() 2021-09-06 12:12:13 +02:00
Ahmet Inan
daa47615d3 do the demodulation online using the first preamble 2021-09-06 00:06:33 +02:00
Ahmet Inan
7b45ee894d use the Theil-Sen estimator on each symbol 2021-09-03 20:52:47 +02:00
Ahmet Inan
8d62a3c90b estimate SFO and CFO via simple linear regression 
and compensate by correcting constellation points
 2021-09-03 20:52:47 +02:00
Ahmet Inan
5c2743f5e7 do not resample 2021-09-03 20:52:47 +02:00
Ahmet Inan
99b6a4e963 use a shortened systematic polar code and CA-SCL decoding 
using SPC(64800, 43072):
mode 6: 8PSK, 2700 Hz BW and about 10 seconds long
mode 7: 8PSK, 2500 Hz BW and about 11 seconds long
mode 8: QPSK, 2500 Hz BW and about 16 seconds long
mode 9: QPSK, 2250 Hz BW and about 18 seconds long

using SPC(64512, 43072):
mode 10: 8PSK, 3200 Hz BW and about 9 seconds long
mode 11: 8PSK, 2400 Hz BW and about 11 seconds long
mode 12: QPSK, 2400 Hz BW and about 16 seconds long
mode 13: QPSK, 1600 Hz BW and about 24 seconds long
 2021-09-03 20:52:09 +02:00
Ahmet Inan
3665d495b7 added demod_or_erase() helper function 2021-08-29 17:47:20 +02:00
Ahmet Inan
d1adc5c5ca erase constellation points outside of radius two 2021-08-28 18:00:19 +02:00
Ahmet Inan
1d02d34e8c Revert "increased guard interval to 1/4" 
This reverts commit 7c7ed0ffd7.
 2021-08-25 11:41:02 +02:00
Ahmet Inan
7c7ed0ffd7 increased guard interval to 1/4 
to reduce ISI and support sample rates 11025 Hz and 22050 Hz
 2021-07-27 13:14:00 +02:00
Ahmet Inan
8d5d7fc0c2 use the DVB recommended T=10 BCH code 2021-07-21 17:15:47 +02:00
Ahmet Inan
6f99db1444 improve CFO estimation using hard decision 2021-07-21 00:12:59 +02:00
Ahmet Inan
357a90805c use a simpler estimation for finer CFO 2021-07-20 21:47:49 +02:00
Ahmet Inan
ef152cc53f scramble user data only using Xorshift32 2021-07-18 04:48:32 +02:00
Ahmet Inan
2645f96056 added support for various operation modes: 
mode 2: 8PSK, 2700 Hz bandwidth and about 10 seconds long
mode 3: 8PSK, 2500 Hz bandwidth and about 11 seconds long
mode 4: QPSK, 2500 Hz bandwidth and about 16 seconds long
mode 5: QPSK, 2250 Hz bandwidth and about 18 seconds long
 2021-06-16 19:54:55 +02:00
Ahmet Inan
463836c41f made number of active carriers a constructor argument 2021-06-16 15:16:01 +02:00
Ahmet Inan
82c279f13b minor cleanup 2021-06-13 14:45:44 +02:00
Ahmet Inan
5a6e5cd995 removed payload CRC check: let user decide 2021-06-13 14:35:51 +02:00
Ahmet Inan
c87bfc6e78 added nrz() helper function 2021-06-13 14:19:46 +02:00
Ahmet Inan
5f4c2cdba9 compute descrambled constellations only once 2021-06-13 11:50:55 +02:00
Ahmet Inan
4683e531fe handle erasures produced by LDPC decoding 2021-06-12 13:27:08 +02:00
Ahmet Inan
a1c0ab3d25 interleave bits for improved LDPC performance 2021-06-12 12:15:34 +02:00
Ahmet Inan
a07fe52134 scramble I and Q using two independent sequences 2021-06-11 22:52:01 +02:00
Ahmet Inan
30f39ce41b estimate SNR using corrected symbols 2021-06-11 11:12:52 +02:00
Ahmet Inan
7e362ae224 estimate SNR using hard decision 2021-06-11 11:12:52 +02:00
Ahmet Inan
7ba95fb000 added LDPC forward error correction 2021-06-11 11:12:52 +02:00
Ahmet Inan
0e9f46efd1 added BCH forward error correction 2021-06-11 11:12:52 +02:00