Safran RX-1 User Manual page 118

synchronization words except when i = 0 (in that case, the frame synchronizer will transmit frames starting from the
frame containing the first occurrence of a correct synchronization word).
 LOCK phase (L) :
In the LOCK mode, the frame synchronizer merely checks the occurrence of a new synchronization word (to within
n errors) every frame. The window in which the synchronization word should be found is enlarged by  N bits (N =
bit slip parameter = 0, 1, 2 or 3 bits) to cope with potential bit slip in the telemetry demodulation process.
 FLYWHEEL phase (F) :
Transmission errors (signal heavily affected by noise) or loss of demodulator lock may occur : the frame
synchronizer will then only return to SEARCH mode after « j » consecutive occurrences of incorrect synchronization
words (number of errors greater than the synchronization threshold). « j » is programmable between 0 and 15
(inclusive) referred to as the LTS (Lock-To-Search) threshold.
Note : Ambiguity Resolution
Ambiguity resolution is performed by the frame synchronizer during the SEARCH phase (and only during this phase).
If the comparison between the expected synchronization word and a given window on the received NRZL data stream
is not successful, a second comparison is made after inversion of the telemetry data. If this second comparison is
successful (to within n bits), the signal inversion is confirmed and the frame synchronizer switches to the CHECK
phase.
© Safran Data Systems – IMP000074 e14r1
RX-1 Compact Operational Receiver
User's Manual
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It cannot be duplicated or distributed without expressed written consent.
Ref. D104047
Is.Rev 08
Previous Ref.: -
Date: 21/06/2021
Safran Data Systems
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Page 118