Канальный кодер и модулятор стандарта DVB-T

Citation preview

Ка а

а

а

а DVB-T.

(

я

)

. .

. . [email protected] . . . . . . .

MAPT 1999 . DVB-T

1

1.

.

2

2. DVB-T. я

2.1 COFDM2.1.1 2.1.2 . 2.1.3 2.1.4 2.1.5 2.1.6 2.1.7 2.1.8 . 2.1.9 .

.

. COFDMCOFDM-

. .

(

).

.

.

2.3 Ка а 2.3.1 2.3.2 2.3.3 2.3.3.2 2.3.3.3 2.3.4 2.3.5 ё 2.3.6 2.3.6.1 2.3.6.2 2.3.6.3 2.3.6.4 2.3.7 2.3.8 2.4 К 2.4.1 2.4.2 2.4.3 2.4.4 2.4.4.1

4 4 5 6 6 6 6 7 7 7

.

В

2.2

4

8

.

9 9 9 10 11 16 16 17 18 18 19 19 20 21 21

. (

).

-

(

).

. (

). . . . . .

. . а

-

. .

-

. (

TPS-

).

. . а

2.5

я.

28

а

2.6

21 21 21 22 22 23

я.

28

3.

.

!

. 4.

.

1.

28

. К

я

DVB-T

.

-

.

, ),

( DVB-T

2

, . .

DVB-T

3

2. DVB-T. я

2.1 COFDM-

.

COFDM (Coded Orthogonal Frequency Division Multiplex) N = 2K ( ё

N

(

),

(

),

C

X.Э

8K ) k-

C (k ) COFDM-

COFDM,

C .

,

X COFDMщ

. -

7.61 (64/7)/2=4.57

.

2.1.1

. C

L=1705 (6817) C (k ) , (k = 0, 1, …, L − 1) . 4.2-1, 4.3-1 4.4-1,

,

2K=2048 (8K=8196) C, ё

-

.2.1.1.1 2.1.1.2.

2K-1705= 343 (8K-6817=1375) .

З

C

Ф:

k, k=0..1704 (6816).

, .( Э

k'-

. =4.7 2K 8K

k' = k - 1704 / 2 (-852..0...+852) k'= k - 6816 / 2 (-3408..0...+3408) ё

i-

, . . C(k)

).

,

. i=0...2047 (8191) i

2K(8K). k

:

2K: i=(k+1196) mod 2048 8K: i=(k+4784) mod 8192

DVB-T

4

:

k’ -852 0 +85 2

k 0 852 1704

i 1196 0 852

.2.1.1.1

k’ -3408 0 +340 8

k 0 3408 6816

2K

i 4784 0 3408

.2.1.1.2

8K

2.1.2

. .

-

, C.

-

X

, .Э

,

, X COFDM-

C, . . COFDM2K (8K): C,

. ,

T

: Tu  ) 2K (8K). : T Ф < 224 (896

-

T

Ф

< Tu ,

COFDM, 2K (8K) X

).

, N/2=1K,

-

Ф

Tu = 224

(896 16.

N=2K

: X (n) = X 1(n) + w X 2(n) X (n + N / 2) = X 1(n) − w k X 2(n) , n = 0,1,..., ( N / 2 − 1) , w = exp(2πj / N ) , X 1(n) X 2(n)  ё ( C ( 2k ) ) ё . k

DVB-T

(

N /2 C (2k + 1) )

5

2.1.3

. N (Tu / ∆ )

COFDMX. Э

ё

-

ё

COFDM-

я

2.1.4

я

.

COFDMё

64/7=9.14

x(n) COFDM.

-

ё

ё (64/7)*2=18.27 (64/7)/2=4.57

.

,

ё

.

.

,

.

2.1.5

COFDM-

.

COFDMx(n)

cos[2n(π / 2) + j sin[ 2n(π / 2)]] (GI)

(GQ)

g(n)

G I (n) = Re[ X (n)]cos[(π / 2)n] − Im[ X (n)] sin[(π / 2)n]

:

GQ (n) = Im[ X (n)]cos[(π / 2)n] + Re[ X (n)] sin[(π / 2)n]

,

cos[(π/2)n]

sin[(π/2)n] .

3

: +1, -1

0.

-

:

G I = + Re[ X (n)],− Im[ X (n + 1)],− Re[ X (n + 2)],+ Im[ X (n + 3)],+ Re[ X (n + 4),... ,

GQ = + Im[ X (n)],+ Re[ X (n + 1)],− Im[ X (n + 2)],− Re[ X (n + 3)],+ Im[ X (n + 4),... . X= +13,4+j7,2; -7,7+j5.6;+ 3.9-j8.4; -0.1-j6.7;… GI=+13,4; -5.6;- 3,9 - 6,7;… GQ= 7,2; -7,7; +8.4; +0.1;…,

2.1.6

(

я COFDM-

(

), ,

я). -

. DVB-T

6

( COFDM-

) .

•

: ,

• •

;

8

-40

; 7,61

2.1.7

0,1

.

. (2K

8K)

FЦ

=2*64/7 =18,285714 ,

-

.

2.1.8

. ё

FЦ

2*(64/7)=18.27

.

(I)

g I (t ) = A(t ) cos(2πf t ) − B(t ) sin (2πf t ) , (Q)

:

g Q (t ) = A(t ) cos(2πf t ) − B(t ) sin (2πf t ) , ,

f =FЦ

2.1.9

/4=(64/7)/2=4,571428 10.

.

. 7.61/2+4.57=8.375

. За

а

а

1) -

ё

а

я

COFDM-

а:

.

Fc.

COFDM-

Fc ? Э R (bitrate), , , Fc ) COFDM, delta-

F =64/7=9.14

2)

,

.Э

.

ё

.Э . 17 EN 300 744 ( . 34). , 1512 Ts=Tu+delta, Tu-

, (2, 4

6-

,

R =R*(188/204)*m*1512/(Tu+delta), R-

ё F =64/7=9.14

(code rate), m=2(QPSK),4(16QAM),6(64QAM). ,

ё

-

R 64/7=R /A, A=(7/64)*R*(188/204)*m*1512/(Tu+delta). DVB-T

7

За

а

ь

а

2)

а

а

COFDMTu+delta .

3) 300 744

1) 2), . 26)

:

-

-

,

5) F .Э

:

224+28=252

(

.

( (16-

)

-

) (

,

-

COFDM-

:

-

-

. . ё

, , ё 252 ,

. 5 EN ).

:

.

, 2304-

6)

" 1705-1512=193

?

, COFDM, -

. ,

! "

2K, delta=1/8, 1512 2048+256=2304 ё -

2K

а

,

,

4)

,

-

1512(

2304 -

ё

3).

3))

ё

Fc

1512

.

c :

ё

-

200

231

,

.

2.2 В

. :

Synchronous Parallel Interface) Interface). 188

(SPI(ASI-Asynchronous Serial EN 50083-9

(

.). Clock

187 Sync 1

2

186 187 Sync 1

3

2

Data (0-7) DVALID PSYNC

.

-

.

: “DVALID”,

188+16

188/204

,

-

.

DVB-T

8

Clock RTS CTS 1

1503 1504

2

1503

1

1504

2

DATA TxD RxD

4-

-

RS-422A LVDS (Low-Voltage Differential Signal):

Э

-

– ( LVDS, IEEE 1596.3 SCI LVDS

): ANSI/TIA/EIA 644 LVDS:

•

EIA/TIA SP3357

±247…±454

• • • • •

±345

100

(

-

); – 100 ; : +1,125…+1,375 ( ±100…±2000 – 90…132 ; : +0,2 …+2,2

+1,25 ); 100

;

(

+1,2 ).

2.3 Ка а

.

2.3.1

. MPEG2,

188

, 47 HEX (0100 0111). ( , 47 HEX

. , ,

-

“0”). DVB

8

. ,

-

B8 HEX (1011 1000).

2.3.2

(

). (

744

.2,

.9, EN 300 748), 2.

, .



.2, . 11, EN 300 (PRBS)

(B8 HEX) 1001101010000000 (

…

).

(B8 HEX) ( DVB-T

B8 HEX)

. 9

c

. (MSB).

,

(47 HEX) , ( . . DISABLE) , (

ENABLE . 47 HEX) 1=1503

, B8 HEX).

(-1

. 1. .2, . 11,EN 300 744 ё Clear /Randomized data input / . 2. DVB-T (EN 300 744) =DVB-MS ( ) - EN 300748. 2.3.3

, B8 HEX 8*188-

-

ё

.

/ ,

Clear. ) MVDS

DVB-S (

(

).

2 3

g1

g 0

g n −k −1

g2

1 .

g1 36

g2 50

g3 98

g4 229

Э 1. 2.

.

P1,P2,..,P188 ( … P189,190,...,P204. , ( . ).

16K1, K2, K3 : g0 59

-

g5 41

g6 65

g7 163

).

P1

. ё

GF(256),

g8 8

g9 30

g10 209

g11 68

g12 189

g13 104

g14 13

g15 59

: . K1 , K3 K1

3. 4.

1,

K3 ,

-

. 188 , 51

,

. 16

P1, .

.

2, .

…

K2

K2

,

P189-P204 (

-

). ,

: P1, P2 ,..., P188, P189, P190,.., P204.

. 1.

(188,204), -

2.

(239,255). 2

(FIFO)

51 188

: .

DVB-T

10

3.

:

-

.

а

2.3.3.1 1.

а-

а а

а

,

ё

. ,

1,

.

,

187 1. (

): 189 126 144 216 249 147 110 72 149 92 73 163 111 52 120 57. 2.

,

(239, 255), 239-

,

(238

1) g(i)

:

59 13 104 189 68 209 30 8 163 65 41 229 98 50 36 59

3.

1,

187

,

:

169 1 22 176 250 139 212 178 33 72 188 12 140 222 137 26 4.

,

(239, 255)

ё 1,

3, 238=187+51

.

,

51

(188,204) 5.

ё

187..0 ( . .

187 )

: 84 235 205 209 215 58 131 104 165 204 44 72 212 53 233 163 6. , 255 : 235 144 116 7 214 239 29 152 56 108 17 31 90 161 110 132

,

(239,255)

:

-

:

, ,

-

,

ё DVB (

-

-

). . (239, 255) (188, 204)

, .

.

:

2.3.3.2

.

я c=a*b (a

ё

-

я b a

255 0 254 ( ( Э)

ё

) b. .

( )

2 -

1) , (

DVB-T

.

)

11

1 ,

. Э

( ,

2) 0 a b

. Na c

: 254 (

.

.

). 1, -

Nb.

2 Nc= (Na + Nb) mod 255 .

c=a*b, a=59(g0), b=144. Nc=(120+227) mod 255=92 , 2) a=19, b=8. Na=14, Nb=3, Nc=17, =152.

Na=120, Nb=227.

1)

З

, =91.

я. (19*8=152). Э 255. ё 59*144=8496>255.

1) , , 2)

-

,

16

Ngi

g(i)

.

g0 59/ 120

g1 36/ 225

g2 50/ 194

g3 98/ 182

g4 229/ 169

g5 41/ 147

-

:

g6 65/ 191

g7 163/ 91

g8 8/ 3

g9 30/ 76

g10 209/ 161

g11 68/ 102

g12 189/ 109

g13 104/ 107

g14 13/ 104

g15 59/ 120

Ngi. 3)

.

Э

,

! .

.

1/ 2 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

DVB-T

1/ 2 1 2 4 8 16 32 64 128 29 58 116 232 205 135 19 38 76 152 45 90 180 117 234 201 143 3 6

12

27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104

DVB-T

12 24 48 96 192 157 39 78 156 37 74 148 53 106 212 181 119 238 193 159 35 70 140 5 10 20 40 80 160 93 186 105 210 185 111 222 161 95 190 97 194 153 47 94 188 101 202 137 15 30 60 120 240 253 231 211 187 107 214 177 127 254 225 223 163 91 182 113 226 217 175 67 134 17 34 68 136 13

13

105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182

DVB-T

26 52 104 208 189 103 206 129 31 62 124 248 237 199 147 59 118 236 197 151 51 102 204 133 23 46 92 184 109 218 169 79 158 33 66 132 21 42 84 168 77 154 41 82 164 85 170 73 146 57 114 228 213 183 115 230 209 191 99 198 145 63 126 252 229 215 179 123 246 241 255 227 219 171 75 150 49 98

14

183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254

Э

c

196 149 55 110 220 165 87 174 65 130 25 50 100 200 141 7 14 28 56 112 224 221 167 83 166 81 162 89 178 121 242 249 239 195 155 43 86 172 69 138 9 18 36 72 144 61 122 244 245 247 243 251 235 203 139 11 22 44 88 176 125 250 233 207 131 27 54 108 216 173 71 142

:

DVB-T

15

З Э

1)

MatLab

Pol=GFPRIMDF(8) Pol = 1

0

1

1

1

0

0

, -

0

1 -

.

1

,

.

2)

Э

255 )

1

(

.

MatLab:

P = GFTUPLE([-1:2^8-2]', 8, 2) P=BI2DE(P)

я

2.3.3.3 GF(256)

a

b

c=a xor b xor

mod 2

(B)

-

. . a=195 (11000011 B), b=203 (11001011 B), =8 (00001000 B). , mod 256, ё c=142.

2.3.4

xor

. ,

204

,

12

. .

1.

17

12

.

-

: 1 2 3 4 5 6 7 8 9 10 11 12

DVB-T

16

12-

,

-

, 12:

, 12- , 13-

2.

-

,…, 12-

. .

12

204

,

.

.

. . 17-

-

(-2-

1)

,

12 12

,

,

:

1 2 3 4 5 6 7 8 9 10 11 12

ё

2.3.5 :

(

). ё

n R = n / m ). DVB ё

(Convolutional Encoder) m ( 5

C0

X

Y R = 1/ 2

2(

.5,

-

R = 1 / 2, 2 / 3, 3 / 4, 5 / 6, 7 / 8 , R = 1/ 2 .

6. 14, EN 300744

.2,

-

. 9, EN 300748). X

(serial output) , ё Y. R > 1/ 2 R = 1/ 2 , “ ”. , , R = 5/6 . n=5 2 ∗ n = 10 X 1 , Y1 , X 2 , Y 2 X 3 , Y 3 , X 4 , Y 4 , X 5 , Y 5 ё X 2 , Y3 , X 4, Y5 m=6 X 1 , Y1 , Y 2 , X 3 , Y 4 , X 5 ( .2, .13, EN 300744). : Convolutional Encoder Puncturing with serial output ( .6, . 14, EN 300744). ё , . DVB-T. Y,

X,

З

я

1.

VDS (

. ): 2-

QPSK R

, MPEG2 Rmpeg2

,

:

=(Rmpeg2*1.08511)/(2*R ё )

R

R ё ё Rmpeg2*1.08511

(1/2,2/3,3/4,5/6,7/8), 1.08511=204/188, Rmpeg2=Clock*8 ( . . ,

,

, ,

R

MPEG2 , Rmpeg2=38.9; 51.8; 58.3; 64.8; 68.0

=42.2,

R

R

=const .

-

R ё =1/2,2/3,3/4,5/6,7/8

ё

-

,

-

-

R ё .

.

=const.

: -

).

Rmpeg2 2*R ё

DVB-T

1.08511 . ,

, ,

2ё

-

17

ё

Rmpeg2*1.08511 R ё =2/3,3/4,5/6,7/8

: 4/3; 6/4; 10/6; 14/8

.

1.1 Т

Т

-

-

DVB-MS

I

-

ё

Q

=

ё

MPEG2 (byte-rate)

(bit-rate)

-

F1=CLOCK (100 K .. .7 )

F2=F1*8

F3=F1*(2 04/188)

F4=F3*8

-

1/2

2/3

3/4

5/6

R 7/8

F5=F4

F6=F4*( 3/4)

F7=F4*( 4/6)

F8=F4*( 6/10)

F9=F4*( 8/14)

2. DVB-T: ё Rmpeg2*1.08511

2-

2; 3/2; 4/3; 6/5; 8/7

2 . R ё =1/2; 2/3,3/4,5/6,7/8

Т

5 .

DVB-T ё -

-

-

ё 1/2

2/3

3/4

5/6

R 7/8

F5=F4* 2

F6=F4*( 3/2)

F7=F4*( 4/3)

F8=F4*( 6/50)

F9=F4*( 8/7)

MPEG2 (byte-rate)

(bit-rate)

-

F1=CLOCK (100 K .. 4.5 )

F2=F1*8

F3=F1*(2 04/188)

2.3.6

F4=F3*8

.

COFDM-

.

,

(

EN 300 744). 16QAM 64QAM)

(

2.3.6.1

2K

8K).

. x v=2 (QPSK), 4 (16 QAM)

. QPSK:

3: .7a, . 16, (QPSK,

b. x

: ё

x0 → b0 ; x1 → b1 ,

DVB-T

b0 ,

ё

ё 6 (64QAM)

 b1 :

18

16-QAM:

ё

x

b0

b3 :

b1 ,

 b2

ё

x0 → b0 ; x1 → b2 ; x 2 → b1 ; x3 → b3 .

64-QAM: b1 , b5 :

x

ё

 b2 ,

ё

b0 , b4 , b3 , x0 → b0 ; x1 → b2 ; x 2 → b4 ; x3 → b1 ; x 4 → b3 ; x5 → b5 .

: x=011000011101…. QPSK: b0 = 0100111... b1 = 110010... b2 = 101... 16QAM: b0 = 001... b1 = 100... 2.3.6.2

.

(64QAM) 64QAM

. 4 (I0,I1,I2,I3) A. A

b3 = 011...

v=2 (QPSK), 4 (16 QAM) 6 6 (I0,I1,I2,I3,I4,I5) 16 QAM, 2 (I0,I1) – QPSK. B 126 , . H w (w = 0, 1, 2, ..., 125) B :

I0: H0 (w) = w I1: H1 (w) = (w + 63) mod 126 I2: H2 (w) = (w + 105) mod 126 I3: H3 (w) = (w + 42) mod 126 I4: H4 (w) = (w + 21) mod 126 I5: H5 (w) = (w + 84) mod 126 , 120B H4 (w) =(w + 21) mod 126 =(120+21) mod 126=15 , 126 : A B, , ё , 6*126*3=2268 ( 284 ). 2.3.6.3

(I4) A. 3 B,

– . ,

. v=2 (QPSK), 4 (16 QAM)

(64QAM)–

-

(

6

). DVB-T

19

Y’

P=12*126=1512 (

2K) Y.

, Y’ 0 P-1.

P=48*126 =6048 ( ё ( ё H(q) (q).

Y H(q) (

,

8K) )

q (H(q))

.18-20 EN 300 744)

.

,

-

. .

H(q)

Y'(q)

(12З

-

q

Y'[H(q)].

)

q, : 1512 (6048) 10-

ё

2K(8K).

я:

>1) >

2048

(i=0..2047).

;

,

ё

,

> 2) > > -

,

1512, -

. 19 EN300744, 2048 , H(q) i. 1512 H(q), q=0..1511.

1512, i=2048

if (H(q) 3)

?

.

( ( .

, , 4- ( 5- , 4788,5169,4663,5044,4916,4541-

.43 EN 300744, Y(k) 9071. , Y(5).

2K)

48,429,679,304,176,557 ) , 11- ( 13-

-

)

. .

я.

2.3.6.4

ё

.

45+131+17=193 1512)

( 2K, 64QAM v=6-

) . .1 48,429,679,304 ,176,557 (

DVB-T

9072 …

ё

, 0

)

20

я.

2.3.7

( ) ) z=Re(z)+jIm(z) 64QAM Y=010111 z=5-j3. Re(z) Im(z) -10 +10 ( 5. ё z=(00101)+j(11101), "-3"

Y (v,

.9a. -7

+7 (64QAM), 64QAM). ё 5-

.

.

2.3.8

z z

r.

r

-

: R 1/√2 1/√10 1/√42

QPSK 16QAM 64QAM c=z*r

(

-

)

C

2.4 К

.

а

-

.

-

: COFDM-

-TPS (Transmission Parameter Signalling)C(k) C wk .

2.4.1

; ;

; -

-

. ё

11.

wk (k=0,..,L-1, (k).

.10 EN300 744. COFDML=1705 (6817) 2K(8K)) 13 wk (k=0,1,..,12)

-

1111111111100.

2.4.2 45 k, 300 744):

-

. (

ё

2K)

177 (

8K) (

.28 EN

.4.2-1 k 2K

8K DVB-T

21

0 48 54 87 141 156 192 201 255 279 282 333 432 450 483 525 531 618 636 714 759 765 780 804 873 888 918 939 942 969 1050 1101 1107 1110 1137 1140 1146 1206 1169 1323 1377 1491 1704 1752 ………

0 48 54 87 141 156 192 201 255 279 282 333 432 450 483 525 531 618 636 714 759 765 780 804 873 888 918 939 942 969 1050 1101 1107 1110 1137 1140 1146 1206 1169 1323 1377 1491 1704 k

C (k ) = 4 / 3 + j 0 C (k ) = 4 / 3 + j 0

:

wk = 0 wk = 1 .

. 1.

4/3

(16/9)

-

.

2. Э

ё

2.4.3

.

-

(

-

). k

ё

,

C

,

131(542)

2K (8K). COFDM4 COFDM. l=0,3,7,11 . . ,

k COFDMk

.

.4.3-1 COFDMl

k

0 1 2 3

12p 3+12p 6+12p 9+12p

p=0,1,2…

,

k

L. 68 COFDM-

COFDM(l=0,1,2,...67).

-

(k)= 4/3+j0 (k)=-4/3+j0 Э

wk =0 wk =1

. -

ё

-

ё

.

2.4.4 TPS17 (68)

. 2K (8K), ё

, . .4.4-1

DVB-T

22

k 2K 34 50 209 346 413 569 595 688 790 901 1073 1219 1262 1286 1687

8K 34 50 209 346 413 569 595 688 790 901 1073 1219 1262 1286 1687 1738 1754 1913 2050 2117 2273 2299 2392 2494 2605 2777 2923 2966 2990 3173 3298 3391 3442 3458 3617 3754 3821 3977 4003 4096 4198 4309 4481 4627 4670 4694 4877 5002 5095 5146 5162 5321 5458 5525 5681 5707 5800 5902 6013 6185 6331 6374 6398 6581 6706 6799

TPSSl.

l(

COFDM

):

Sl=0 , Sl=1 ,

l(k)= l(k)=

0(k)=

1+j0 0(k)=-1+j0

l-1(k)

-

l-1(k)

wk =0 wk =1,

S0

COFDM-

2.4.4.1

(l=0)

68

.

. S0-S67

4.4.1-1…4.4.1-6

.

.4.4.1-1 C S0 S1-S16 S17-S22 S23,S24 S5,S26

1/0 0011010111101110 1100101000010001* 010111 . 4.4.1-2 . DVB-T

ё

-

-

4.4.1-3 23

S27,S28,S29 S30,S31,S32

000 .

S33,S34,S35 S36,S37

000 .

ё

4.4.1-4 R 4.4.1-5

(∆/ Tu)

S38,S39

.

4.4.1-6

(2K 8K)

S40-S53 S54-S67 *

,

ё

-

. .4.4.1-2

S23,S24 00 01 10 11

1 2 3 4 .4.4.1-3 S25,S26

00 01 10 11

QPSK 16QAM 64QAM

.4.4.1-4 S30,S31,S32 000 001 010

ё

R

1/2 2/3 3/4

011 100 101 110 111

5/6 7/8

.4.4.1-5 S36,S37

(∆/ Tu)

00 01 10 11

1/32 1/16 1/8 1/4 4.4.1-6 S38,S39 DVB-T

24

00 01 10 11

2K 8K

2.4.4.1.1

.

14

S54…S67 . 14ё

2,

S1…S53 -

, K1,K2,K3

.

2 3

g1

g0

g n −k −1

g2

1

1

2

. ,

-

1,

,

0,-

-

. 8

(

-

): g0 g1 g2 g4 g5 g6 g8 g9 Э 1. 2.

: . K1

1, S1,

-

K2

K3

. 53

,

,

,

-

,

. 3. 4.

K3 K1

60 2,

.

. S54…S67 ( ,

14 …

,

. K2 -

). :S1, S2 ,..., S53, S54, S55,.., S67.

. 60

(53,67)

(113,127). Т

а

а БЧХ:

1) )

MatLab

(7,4):

= DVB-T

25

Pg = BCHPOLY(7,4) Pg = 1101 )

:

-

=MSB, . .

A=randint(4,1) A= 0 1 0 1 )

-

:

(

=LSB)

-

3 B=encode(A,7,4,'bch') B= 1 1 0 0 1 0 1 2)

(127,113).

Pg = BCHPOLY(127,113) ё g0

: g1

g2

g4

g5

g6

g8

g9 :

A=randint(113,1) B=encode(A,127,113,'bch') 3) A=randint(113,1)

=MSB,

-

, . .

A=zeros(113,1) A(113)=1 14

: DVB-T

26

1 1 0 1 1 1 0 1 1 0 0 0 0 1 4)

, (

) 53 ,

,

.Э

-

113

.

67

(53+14

-

)

,

. -

, . . . "

( OFDMe-mail

..."

).

. : delta=1/4, Ts=Tu+delta=280

.

1) ,

1512/280=27/5=5,4

280

1512

280

, . . (

1512

,

, COFDM...").

"

2)

1705/280=341/56=6.089285714286 280

1705

, . . .

1705

.

280

3) COFDM.Э

COFDM -

+ OFDM,

Ts 1705

1512 ,"

"

. 4)

? . DVB-T

ё 27

1512

. (0...1511)

ё

Э

, k507

.

?

, (k=0,..,1511). ( 83 (

, ), ),

507+83=590. 5) (0..1704)

ё .

. ё

ё

ё

,

. . ,

ё

-

ё

ё

.

. ,

, .

2.5 С

а

я. 4

HEX

68 HEX). -

(47

.

:

68 COFDM(47 HEX

-

,

),

2.6 У

68 HEX) COFDM.

а

188

(

204

)

(

я.

: ё M (QPSK,16QAM,64QAM) COFDM-

3.

(

. ё )

R,

(2K/8K),

∆

-

Tu.

.

[1] ETSI: "Digital broadcasting systems for television, sound, and data services; Framing structure, channel coding and modulation for digital terrestrial television (DVB-T). E TS 300 744",1997 ( www.dvb.org). DVB-T

28

[2] .

, .

,“ ”.//

[3] .

, "Э , 1998, № 10, . 56-64.

-

-

-

, 1999, №11, .52-56. ". //

-

[4] N. Pickford, “Laboratory testing of DTTB modulation systems”, Laboratory Report 98/01, Australia Department of Communications and Arts, June 1998. ( www.commslab.gov.au ) [5] . ," №4,1999,c.66-70.

:ATSC-DVB-ISDB"// 625,

[6] ACTS: VALIDATE (Project AC106 ) "Verification and Launch of Integrated Digital Advanced Television in Europe", Final Report ( www.bbc.co.uk ). [7] ETSI: "Digital Video Broadcasting (DVB); DVB mega-frame for Single Frequency Network (SFN) synchronisation. Technical Standard TS 101 191",1998 ( www.etsi.org ). [8] ACTS: MOTIVATE (Project AC318) "Mobile Television and Innovative Receivers" (http://b5www.berkom.de ). [9] The EuroMHEG Specification V1.0 (

www.dtg.org.uk )

[10] ACTS: ITTI (Project AC321) "Interactive Terrestrial TV Integration" (http://www.infowin.org ).

DVB-T

29