DVB-S2
DVB-S2 :
1) HDTV.
SDTV. SAT , .
2) Ka-.
, , . , - KU-.
3) SAT .
, .
. DVB-S2 - , , , , , , , . C DVB-S2 IP-.
, , . .
DVB-S2 \ (C\N). , MPEG-2 TS, , . DVB-S2 , MPEG, IP ATM.
DVB-S/S2 MPEG (. . ..)
.
. ( ) . , , -- (Bose-Chaudhuri-Hocquenghem, BCH), LDPC , , , . LDPC 64800 , , 16200 . 1/4, 1/3, 2/5, 1/2, 3/5, 2/3, 3/4, 4/5, 5/6, 8/9 9/10, . 1/4, 1/3, 2/5 QPSK , .
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DVB-S2 (.1). , QPSK 8 PSK, . , , . , 16 APSK 32 APSK, , , , (LN), . , , /. APSK . , . DVB-S2 QPSK, 8PSK, 16APSK 32APSK. . , . , , , . , \ , , . , . 16APSK 32APSK . 16 32 QAM .
, 0,5 4 . . DVB-S2 ( FDM ). , Rs (BW=Rs). , Rs . , . , , C/N -2,4 dB ( QPSK 1/4) 16 dB ( 32PSK 9/10). 10-7 DVB-S2, DVB-S/DVB-DSNG, TS TV 5 /. 20-35% DVB-S DVB-DSNG 22,5 dB Ru.
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DVB-S2
K | QPSK | 8PSK | ||
30 (/) | "/" () | 30 (/) | "/" () | |
1/2 | 24.85 | 1.2 | - | - |
3/5 | 29.85 | 1.84 | 44.78 | 3.15 |
2/3 | 33.21 | 2.05 | 49.81 | 3.79 |
3/4 | 37.35 | 2.47 | 56.03 | 4.59 |
4/5 | 39.85 | 2.84 | - | - |
5/6 | 41.54 | 3.16 | 62.31 | 5.59 |
7/8 | - | - | - | - |
8/9 | 44.35 | 3.9 | 66.52 | 6.67 |
9/10 | 44.90 | 4.07 | 67.35 | 6.87 |
, Hughes, , 15 MODCOD VSAT. MODCOD VSAT MODCOD (, QPSK, FEC ½) / , VSAT . , 8 8 /.
, . MODCOD . , -- , , , .
, VSAT- , . ( " " -- clear sky). -- -- , 80..90% . , , DVB-S DVB-S2 40 150%, , .
, DVB-S2 VSAT :
- VSAT .
- VSAT- , .
- .
- VSAT .
- .
. LDPC
Es/No (dB) FEC 64 800 | ||
QPSK 1/4 | 0,49 | -2,35 |
QPSK 1/3 | 0,66 | -1,24 |
QPSK 2/5 | 0,79 | -0,3 |
QPSK 1/2 | 0,99 | |
QPSK 3/5 | 1,19 | 2,23 |
QPSK 2/3 | 1,32 | 3,1 |
QPSK 3/4 | 1,49 | 4,03 |
QPSK 4/5 | 1,59 | 4,68 |
QPSK 5/6 | 1,65 | 5,18 |
QPSK 8/9 | 1,77 | 6,2 |
QPSK 9/10 | 1,79 | 6,42 |
8PSK 3/5 | 1,78 | 5,5 |
8PSK 2/3 | 1,98 | 6,62 |
8PSK 3/4 | 2,23 | 7,91 |
8PSK 5/6 | 2,48 | 9,35 |
8PSK 8/9 | 2,65 | 10,69 |
8PSK 9/10 | 2,68 | 10,98 |
16APSK 2/3 | 2,64 | 8,97 |
16APSK 3/4 | 2,97 | 10,21 |
16APSK 4/5 | 3,17 | 11,03 |
16APSK 5/6 | 3,3 | 11,61 |
16APSK 8/9 | 3,52 | 12,89 |
16APSK 9/10 | 3,57 | 13,13 |
32APSK 3/4 | 3,7 | 12,73 |
32APSK 4/5 | 3,95 | 13,64 |
32APSK 5/6 | 4,12 | 14,28 |
32APSK 8/9 | 4,4 | 15,69 |
32APSK 9/10 | 4,45 | 16,05 |
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DVB-S2 :
(Constant Coding and Modulation) - (,-);
VCM (Variable Coding and Modulation) , , ;
ACM (Adaptive Coding and Modulation) ( ) , , , , - . , DVB-RCS, , , , , .
(CM):
CCM (Constant Coding andModulation) .
( / );
VCM (Variable Coding andModulation) . / ( / );
ACM (Adaptive Coding andModulation) .
, (. 2). (
, ). ,
:
36 51 53,7
(ROF) 30,9 / 29,7 /
.. (0,20) (0,25)
QPSK ¾ 8PSK 2/3
, / c 46,0 58,8
SD! 10 SDTV MPEG2 13 SDTV MPEG2
21 SDTV h.264 26 SDTV h.264
HD! 2 HD MPEG2 3 HD MPEG2
5 HD h.264 6 HD h.264
, , . , , .
DVB-S2 ( ) α. DVB-S α = 0,35, α = 0,20 α = 0,25. , , . , α , . .
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. α
. MPEG-2, . DVB-S2 , / . , . , , ( ) . 64 800 ( 16 200) , LDPC/BCH FEC, (Header, 80 ), . (, ), (MPEG-2-TS, ), (CCM, ACM) . . , , . BB , 90 . , . . . -, , "" , . -, , , . 7/64, , "" . , , , , . 90 , . 16 , . .. , . VCM (Variable Coding and Modulation) ACM (Adaptive Coding and Modulation) 1 , . DVB-S2 .
APSK (.. ) , SAT , , , 32 APSK. (LNC) . . , (.. ), C/N.
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ACM, , IP unicast. 4-8 , , . ACM Ka- , . . .
. DVB-S2 ACM.
ACM , DVB-S2 , , , ACM .
ACM . / . C/N+1.
DVB-S2 , . , , .
. 1. HughesNet.
HughesNet, DVB-S2. HN7000S VSAT ( ) ; , . , , () / , . - DVB-S2 BER , FEC .
-- -- MODCOD -- , , VSAT, , , . VSAT. MODCOD , FEC VSAT-.
MODCOD VSAT FEC , , VSAT (.. ). VSAT ( VSAT VSAT. . 100% 1 (). 0.987). , , 8PSK FEC, 3 /.
. 2. MODCOD.
.
, . , , , . , , . , .
99.95%, ~113%, ~55%.