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Unformatted text preview: mbols. Control information which indicates the readiness
of the channel is passed to the layer above.
The spacecraft telecommand channel decoder within the receiving end of the Coding layer
awaits this symbol stream containing an Acquisition sequence, a CLTU Start sequence, and
the set of sequential TC Codeblocks which carry the encoded TC Transfer Frame information
bits. The Acquisition sequence provides a preamble for symbol synchronization purposes.
The CLTU Start sequence marks the start of the first TC Codeblock (which contains the
leading bits of a TC Transfer Frame). TC Codeblock decoding begins after the CLTU Start
sequence is detected: the TC Codeblocks are sequentially decoded to reconstruct the
information (Input TC data) bits which, together with control data, are passed to the layer
above which reassembles the TC Transfer Frame. If the Input TC data have been
randomized, it is here that they are derandomized before being passed to the layer above.
After transmission of all TC Codeblocks contained within the CLTU, a Tail sequence is
transmitted which signals the end of the CLTU, and may be followed by an (optional) Idle
sequence and more...
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- Spring '14