Notes 1 the transmitted codeblock is the received

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Unformatted text preview: ock is the received data entity physically fed into the R-S decoder. (As an example, when E = 16 and k = 223, using I=5 and no virtual fill, the length of the transmitted codeblock will be 10,200 bits; if virtual fill is used, it will be incrementally shorter, depending on the amount used.) 2 The Logical Codeblock is the logical data entity operated upon by the R-S decoder. It can have a different length than the transmitted codeblock because it accounts for the amount of virtual fill that was introduced. (As an example, when E = 16 and k = 223, for I=5 the logical codeblock always appears to have exactly 10,200 bits in length.) CCSDS 131.0-B-2 Page 4-4 August 2011 CCSDS RECOMMENDED STANDARD FOR TM SYNCHRONIZATION AND CHANNEL CODING 3 The R-S codeblock is partitioned as shown in figure 4-1. ATTACHED SYNC MARKER TRANSMITTED CODEBLOCK TRANSFER FRAME (UNCODED) SYNC • • • • • SYNC • • R-S CHECK SYMBOLS TRANSFER FRAME (UNCODED) R-S CHECK SYMBOLS SYNC • VIRTUAL FILL (OPTIONAL) LOGICAL CODEBLOCK Figure 4-1: Reed-Solomon Codeblock Partitioning 4.3.8.2 shall: Virtual fill shall be used to logically complete the codeblock. If used, virtual fill a) consist of all zeros; b) not be transmitted; c) not change in length for a Mission Phase on a particular Physical Channel; d) be inserted only at the beginning of the codeblock (i.e., after the attached sync marker but before the beginning of the transmitted codeblock); e) be inserted only in integer multiples of 8I bits. 4.3.9 4.3.9.1 DUAL BASIS REPRESENTATION Dual basis representation shall be used. 4.3.9.2 The order of transmission shall be dual basis eight-bit string z0, z1, . . ., z7 (i.e., with z0 transmitted first). 4.3.9.3 The relationship between the two representations shall conform to the following two equations: CCSDS 131.0-B-2 Page 4-5 August 2011 CCSDS RECOMMENDED STANDARD FOR TM SYNCHRONIZATION AND CHANNEL CODING 10001101 1 1 [z0, . . ., z7] = [u7, . . ., u0] 1 1 1 1 0 1 1 0 1 0 0 1 1 1 0 1 0 1 1 0 0 0 1 1 0 1 1 1 0 1 1 1 1 1 1 1 0 0 1 0 1 0 1 1 0 1 1 1 0 0 0 1 1 1 1 0 0 1 [u7, . . ., u0] = [z0, . . ., z7] 1 0 1 1 1 1 0 1 1 1 0...
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