Ccsds Data De-Randomizer - Safran CORTEX Series User Manual

When the synchronization input is set to I ( respectively Q) (see section above)., the frame
synchronizer searches the synchronization word on I and Q channels (at Frame synchronizer input)
and automatically route the selected channel to the I (respectively Q) ECL output.
M &
ODULATION
DECODING
QPSK
OQPSK
BPSK
AQPSK (note 1)
UQPSK
QPSK + Viterbi single
BPSK + Viterbi
QPSK + Dual Viterbi
OQPSK + Dual Viterbi
8PSK
8PSK + TCM
Note 1: Same bit rate but asynchronous I and Q clocks.
Note 2: Enables to retrieve the original data stream even if the on-board data process is unknown to
the operator.
Note 3: Providing that correct 8PSK de-mapping (normal or Gray) has been selected.
3.4.3

CCSDS Data De-randomizer

Randomization technique can be used:
to maintain bit or symbol synchronization on the telemetry processing chain, by always having a
-
minimum bit transition density on the received telemetry signal,
to avoid a false carrier lock that can occur on a modulated signal with periodic data,
-
- to avoid ambiguous data patterns that allow decoder false lock.
De-randomization by the CORTEX HDR complies to the CCSDS recommendation 101.0-B-3 (Blue
Book - May 1992). The pseudo-random sequence is generated using the following polynomial:
Customized de-randomization can also be used (refer to the following paragraph).
© Safran Data Systems – IMP000074 e14r1
HIGH DATA RATE RECEIVER
HDR-4G+ USER'S MANUAL
NRZ-L, BP-L
Ambiguity resolved
Ambiguity resolved (note 3)
Specification (note 2)
h(x) = x8 + x7 + x5 + x3 + 1
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It cannot be duplicated or distributed without expressed written consent.
Ref. DTU 100782
Is.Rev 3.5
Date: June 1, 2021
DNRZ
Specification (note 2)
Not Applicable
Ambiguity resolved
Not Applicable
Not Applicable
Safran Data Systems
NRZ-M/S
BP-M/S
Ambiguity resolved
Specification (note 2)
Specification (note 2)
Ambiguity resolved
Specification (note 2)
Specification (note 2)
Specification (note 2)
Ambiguity resolved
Specification (note 2)
.
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