Comtech EF Data SDM-9000 - Manual (Page 211)

SDM-9000 Satellite Modem Options
Rev. 4 A–25
A.2.9 Inner Coder/Decoder
The transmit convolutional coder is a standard k = 7, rate 1/2 (G1 = 171, G2 = 133),
followed by a programmable puncturing unit. Code rates supported are 1/2, 3/4, and 7/8.
A.2.9.1 Punctured Operation
The DVB puncturing scheme differs from that specified by IESS-308 (INTELSAT), and
is shown in Figure A-20.
G1(1) G1(2) G1(3)
G2(1) G2(2) G2(3)
G1(1)
G2(1)
G2(2)
G1(3)
RATE 1/2
CONVOLUTIONAL
ENCODED DATA
RATE 3/4 ENCODED
PUNCTURED CHANNEL
DATA
G1(1) G1(2) G1(3)
G2(1) G2(2) G2(3)
G1(1)
G2(1)
G2(2)
G2(3)
RATE 7/8 ENCODED
PUNCTURED CHANNEL
DATA
G1(4) G1(5) G1(6)
G2(4) G2(5) G2(6)
G1(7)
G2(7)
G2(4)
G1(5)
G2(6)
G1(7)
B) RATE 7/8 PUNCTURE PATTERN
A) RATE 3/4 PUNCTURE PATTERN
= PUNCTURED SYMBOL (DELETED)
X
Y
I
Q
X
Y
I
Q
RATE1/2
CONVOLUTIONAL
ENCODED DATA
Figure A-20. DVB Puncturing