The random sequence is generated by the bit

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Unformatted text preview: Red with the decoded data, restoring the original data form. The random sequence is generated by the Bit Transition Generator (BTG). 3.3.1.1 Random Sequence. following polynomial: The random sequence shall be generated using the h(x) = x8 + x6 + x4 + x3 + x2 + x + 1 This sequence repeats after 255 bits, continuing as needed. The first 40 bits of the sequence are 1111 1111 0011 1001 1001 1110 0101 Increasing Time----------------------------------> CCSDS 201.0-B-3 Page 3-3 1010 0110 1000 June 2000 CCSDS RECOMMENDATION FOR TELECOMMAND: CHANNEL SERVICE Figure 3-3 is a basic logical diagram of the BTG. INPUT DATA RANDOMIZED INPUT DATA X8 X7 X6 X5 X4 X3 X2 X1 Random sequence Initialize to an “all ones” state. = Single Bit Delay = Modulo-2 adder (Exclusive-OR) Figure 3-3: Bit Transition Generator Logic Diagram 3.3.1.2 APPLICATION OF THE RANDOMIZER. The randomization is applied at the transmitting end, only to the Input Data. The BTG is preset to the “all-ones” state and then is exclusively ORed, bit by bit, with the Input Data until...
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