Unformatted text preview: te Physical Layer Operations Procedures (PLOPs). CCSDS 201.0-B-3 Page 4-2 June 2000 CCSDS RECOMMENDATION FOR TELECOMMAND: CHANNEL SERVICE 4.3.3 PHYSICAL LAYER OPERATIONS PROCEDURES (PLOPS) A PLOP consists of a sequential application of the various CMMs in order to activate and
deactivate the physical telecommand channel. Two procedures, PLOP-1 and PLOP-2, are
currently defined. The selection of PLOPs is mission-specific.
PLOP-1. PLOP-1 is a procedure for individually radiating CLTUs, whereby the
spacecraft TC decoder is always forced into the INACTIVE state (S1) by deactivating the
physical telecommand channel after the end of transmission of each CLTU (or CLTU
followed by an Idle Sequence).
PLOP-1 invokes the sequence of CMMs shown in Figure 4-1. Note that “unmodulated” is
defined as the state in which no telecommand modulation is present.
BEGIN COMMAND SESSION 1. CMM-1: UNMODULATED CARRIER ONLY 2. CMM-2: CARRIER MODULATED WITH
ACQUISITION SEQUENCE 3. (CMM-4): (OPTIONAL: CA...
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