Comtech EF Data SDM-300A, Инструкция по установке и эксплуатации

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SDM-300A Satellite Modem Options
Rev. 4 A–65
A.2.1.4 Reed-Solomon Decoder
Refer to Figure A-18 for a block diagram of the Reed-Solomon decoder section.
The Reed-Solomon decoder section includes the following circuits:
•
Serial/Parallel Converter
•
RAM Deinterleaver
•
Parallel/Serial Converter
•
Reed-Solomon Codec (decoder section)
•
Synchronous Descrambler
D M X DAT
(S E R IA L)
JP 2
PA R A LL E L
S Y N C H RO N O US
R S
S E R IA L
R A M U N IQ U E W O R D
R X S AT D AT
(S E R IA L)
JP 2
R X S ATC L K
JP 2 D E TE C TOR
C O NV E R TE R
PA R A L LE L T O
D E IN T E R LE AV E R
C O D E C
(D E C O D E R S E C T IO N )
D E IN T E R L E AV E R
D E S C R A M B L ER
C O N V E RT E R
T O S E R IA L
D M XC LK
JP 2
A D D R ES S
G EN E RATO R
R S T IM IN G C O N T R O L LE R
U 3 U 3
U 3
U3 U 3
U3
U 2
U 1
Figure A-18. Reed-Solomon Decoder Section Block Diagram
The data and clock signals come from the demultiplexer on the interface PCB, and are
sent to the Reed-Solomon decoder section.
The data is sent through a serial/parallel converter. Because it was block interleaved by
the encoder, the data must pass through a de-interleaver with the same depth as the
interleaver used on the encoder. The de-interleaver is synchronized by the detection of
the unique words, which are placed at the end of each page by the interleaver on the
encoder.
Once the de-interleaver is synchronized to the incoming data, the data is reassembled into
its original sequence, in accordance with the INTELSAT-308 Rev. 6B specification. The
data is then sent to the Reed-Solomon outer decoder.