Such a lockout may occur if the start pattern of one

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Unformatted text preview: nchronization lockout. Such a lockout may occur if the start pattern of one CLTU is not detected (leaving the decoder in SEARCH state) and a start pattern exists over the last bits of the last frame of that CLTU and the first bits of its Tail Sequence. This creates an erroneous but temporary CLTU start (DECODE state), causing the true start of the following CLTU to be missed. The added Idle Sequence prevents this from happening. PLOP-2 invokes the sequence of CMMs shown in Figure 4-2. Note that “unmodulated” is defined as the state in which no telecommand modulation is present. CCSDS 201.0-B-3 Page 4-4 June 2000 CCSDS RECOMMENDATION FOR TELECOMMAND: CHANNEL SERVICE BEGIN COMMAND SESSION 1. CMM-1: UNMODULATED CARRIER ONLY 2. CMM-2: CARRIER MODULATED WITH ACQUISITION SEQUENCE 3. (CMM-4): (OPTIONAL: CARRIER MODULATED WITH IDLE SEQUENCE) 4. CMM-3: CARRIER MODULATED WITH TC DATA: TRANSMIT ONE CLTU 5. (CMM-4): (OPTIONAL: CARRIER MODULATED WITH IDLE SEQUENCE) 6. REPEAT (4) AND (5) FOR EACH C...
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This document was uploaded on 03/06/2014.

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