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Unformatted text preview: 1 0 0 1 1 1 1 1 0 0 0 0 1 1 1 0 0 0 0 1 1 0 1 1 1 1 0 1 1 0 0 1 1 0 1 1 0 0 0 0 0 1 0 0 1 0 1 0 0 and NOTES 1 Discussion of dual basis representation is contained in 4.4.2. 2 Further information relating the dual basis (Berlekamp) and conventional representations is given in annex F. Also included is a recommended scheme for permitting the symbols generated in a conventional encoder to be transformed to meet the symbol representation required by this document. 4.3.10 CODEBLOCK SYNCHRONIZATION Codeblock synchronization of the Reed-Solomon decoder shall be achieved by synchronization of the Attached Sync Marker associated with each codeblock. (See section 8.) NOTE – At the receiving end, the ambiguity between true and complemented data must be resolved so that only true data is provided to the Reed-Solomon decoder. Data in NRZ-L form is normally resolved using the 32-bit Attached Sync Marker, while NRZ-M data is self-resolving. 4.4 4.4.1 DISCUSSION SYMBOL INTERLEAVING Symbol interleaving is accomplished in a manner functionally described with the aid of figure 4-2. (It should be noted that this functional description does not necessarily correspond to the physical implementation of an encoder.) CCSDS 131.0-B-2 Page 4-6 August 2011 CCSDS RECOMMENDED STANDARD FOR TM SYNCHRONIZATION AND CHANNEL CODING R‐S ENCODER #1 S1 S2 • • • IN OUT R‐S ENCODER #I Figure 4-2: Functional Representation of R-S Interleaving Data bits to be encoded into a single Reed-Solomon Codeblock enter at the port labeled ‘IN’. Switches S1 and S2 are synchronized together and advance from encoder to encoder in the sequence 1,2, . . ., I, 1,2, . . ., I, . . ., spending one R-S symbol time (8 bits) in each position. One codeblock will be formed from kI R-S symbols entering ‘IN’. In this functional representation, a space of 2EI R-S symbols in duration is required between each entering set of kI R-S information symbols. Because of the action of S1, each encoder accepts k of these symbols, with each symbol spaced I symbols apart (in the original stream). These k symbols are passed directly to the o...
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