0 b 3 page 3 4 june 2000 ccsds recommendation for

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: duce the seven parity bits: g(x) = x7 + x6 + x2 + 1 CCSDS 201.0-B-3 Page 3-4 June 2000 CCSDS RECOMMENDATION FOR TELECOMMAND: CHANNEL SERVICE The code generator implementation is shown in Figure 3-4. Note that the shift registers are initialized to zero. The ganged switch is in position 1 while the 56 TC data bits are being transmitted, in position 2 for the seven parity bits, and in position 3 for the appended fill bit. INFORMATION BITS I 0 • • • I 55 (1) (1) (2) (2) CODED DATA OUTPUT (3) (3) ZERO P 6 P 5 P 4 P 3 P 2 P 1 P 0 X0 X1 X2 X3 X4 X5 X6 ZERO I PARITY BITS Figure 3-4: (63,56) Modified BCH Code Generator 3.3.3 FILL BITS If the Input Data do not fit exactly within an integral number of TC Codeblocks, the last octet(s) and ONLY the last octet(s) of the information field of the last Codeblock within the CLTU may contain “Fill” bits. The pattern of the Fill shall consist of a sequence of alternating “ones” and “zeros” starting with a “zero”. The Coding layer may require the introduction of these fill bits in th...
View Full Document

Ask a homework question - tutors are online