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Unformatted text preview: ervice layers are working normally by
having enough signal energy to achieve bit synchronization with the received
data stream. If bit lock is not achieved, this may indicate that the Channel
Service layers are operating at a non-nominal performance level and that the
TC Frame rejection rate may be correspondingly abnormally high.
When Bit 17 is used and set to value “0”, this indicates BIT LOCK
ACHIEVED. When Bit 17 is used and set to value “1”, this indicates NO BIT
This flag is not part of the COP protocol, and may therefore be used by
Agencies or Centers for local enhancements to TC operations. If not used, it
shall be set permanently to value “0”.
The single NO BIT LOCK flag applies to all Virtual Channels. This input
parameter to the CLCW is updated whenever a change is signaled by the
Channel Service. (c) LOCKOUT flag (Bit 18)
Bit 18 is set to value “1” to indicate LOCKOUT whenever a Type-A TC
Frame is received on a particular Virtual Channel which violates certain frame
acceptance checks. Once the FARM is in LOCKOUT, all subsequent Type-A
TC Frames are rejected by that FARM until the condition is cleared. The
conditions for entering and exiting LOCKOUT for the COP are specified in
Reference . If the FARM is not in LOCKOUT, Bit 18 shall be set to value
Necessarily, separate LOCKOUT flags shall be maintained for each Virtual
Channel. CCSDS 202.0-B-2 Page 4-12 CCSDS HISTORICAL DOCUMENT November 1992 CCSDS HISTORICAL DOCUMENT
CCSDS RECOMMENDATION FOR TELECOMMAND: DATA ROUTING SERVICE (d) WAIT flag (Bit 19)
When Bit 19 is set to value “1”, this indicates that the receiving end of the
Transfer layer is unable to pass data to the Segmentation layer on a particular
Virtual Channel. This may be caused by temporary lack of storage and/or
processing resources in the receiving end of the Transfer or higher layers.
When Bit 19 is set to value “1” (i.e., WAIT) for a particular Virtual Channel,
all further Type-A TC Frames on that channel shall be rejected...
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This document was uploaded on 03/06/2014.
- Spring '14