ccsds 131.0-b-2

CCSDS RECOMMENDED STANDARD FOR TM SYNCHRONIZATION AND CHANNEL CODINGCodeword, or Transfer Frame. The sequence generator shall be initialized to the all-onesstate at the start of each Codeblock, Codeword, or Transfer Frame.NOTE – The first 40 bits of the pseudo-random sequence from the generator are shownbelow. The leftmost bit is the first bit of the sequence to be exclusive-ORed withthe first bit of the Codeblock, Codeword, or Transfer Frame; the second bit of thesequence is exclusive-ORed with the second bit of the Codeblock, Codeword, orTransfer Frame, and so on.1111 1111 0100 1000 0000 1110 1100 0000 1001 1010 . . . .9.5 LOGIC DIAGRAMNOTE – Figure 9-2 represents a possible generator for the specified sequence.DATA IN(Codeblock, Codeword,or Transfer Frame)DATA OUT(RandomizedCodeblock, Codeword,or Transfer Frame)X 8X 7 X 6 X 5 X 4 X 3 X 2 X 1Pseudo-randomsequenceInitialize to an ‘all ones’ state for each Codeblock, Codeword, orTransfer Frame during ASM period= Modulo-2 adder(Exclusive-OR)= Single Bit DelayFigure 9-2: Pseudo-Randomizer Logic DiagramCCSDS 131.0-B-2 Page 9-3 August 2011