HIGH DATA RATE RECEIVER
HDR-4G+ USER’S MANUAL
Ref. DTU 100782
Is.Rev 3.5
Date: June 1, 2021
© Safran Data Systems – IMP000074 e14r1
This document is the property of Safran Data Systems.
It cannot be duplicated or distributed without expressed written consent.
(255,239) Reed-Solomon Decoding 3.4.7
This (255,239) Reed Solomon is recommended by the ECSS for links which have 4D-8PSK-TCM
modulation:
J = 8 bits per R-S symbol
Conventional and dual basis supported
E = 8 R-S symbol error correction capability within a R-S codeword (coded to decoded
information ratio = 255/239),
Interleaving depth: 1 to 8
Virtual filling for shorten RS code
Other characteristics: refer to: ECCS - Space data links – Telemetry synchronization and
channel coding ECCS-E-50-01.
Interleaving depth and virtual filling length are automatically deduced from the CADU length set by the
operator with the same formula as for RS (255,223).
(10,6) Reed-Solomon Frame Header Decoding 3.4.8
This CCSDS shorten (10,6) Reed Solomon can be optionally used for transfer frame header error
control:
J = 4 bits per R-S symbol
E = 2 R-S symbol error correction capability within a R-S codeword,
Other characteristics: refer to: CCSDS – AOS Space Data Link Control- CCSDS 732.0-B-1 Blue Book.
Specific Decoding 3.4.9
The HDR provides specific decoding scheme, i.e. separate de-randomizer and Reed Solomon
decoding on each I and Q outputs of the demodulator.
On each I and Q separate outputs, the supported format of a CADU is the following:
CADU length: 9424 bytes
19 RS frames per CADU
RS frame format: 2 interleaved (223,255)RS blocks with 7 bytes of virtual filling per RS block
CADU synchronization word: RS encoded
De-randomizer: CCSDS type.
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