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Decoder (131.0-B-5) ​

Group: CCSDS > Telemetry (TM)

CCSDS 131.0-B-5 TM synchronization and channel coding decoder

Parameters ​

Synchronization ​

Decoding Strategy ​

  • Description: Which modulation is used for symbols.
  • Automation reference: DecodingStrategy
  • Type: enumeration
IdentifierValueDescription
BasebandBaseband DecodingFinds syncwords in baseband symbol stream before decoding.
SequentialSearchSequential SearchResolves code node synchronization by stepwise searching until syncwords are found.
NoneNoneAssumes encoding always is synchronized with input symbol stream.

Modulation ​

  • Description: Which modulation is used for symbols.
  • Automation reference: Modulation
  • Enablement: DecodingStrategy == Baseband
  • Type: enumeration
IdentifierValueDescription
BPSKBPSKBinary Phase Shift Keying.
QPSKQPSKQuadrature Phase Shift Keying.
PSK88-PSK8 point Phase Shift Keying.

Input type ​

  • Description: MISSING
  • Automation reference: InputType
  • Enablement: DecodingStrategy in [SequentialSearch, None]
  • Type: enumeration
IdentifierValueDescription
HardBitHard bitsPacked in bytes
SoftBitU8Soft bits (unsigned 8bit)
SoftBitF32Soft bits (32bit float)

Syncword threshold ​

  • Description: Number of flipped bits to accept
  • Automation reference: SyncwordThreshold
  • Enablement: DecodingStrategy in [SequentialSearch, None] && InputType == HardBit
  • Type: integer

General ​

Coding Method ​

  • Description: Which coding method to use
  • Automation reference: Coding
  • Type: enumeration
IdentifierValueDescription
UncodedUncoded
ConvolutionalConvolutional
ReedSolomonReed-Solomon
ConcatenatedConcatenated Code
TurboTurbo
LDPC_TMFramesLDPC (TM Frames)LDPC coding (of a Transfer Frame)
LDPC_SMTFLDPC (SMTF stream)LDPC coding (of a stream of SMTFs)

Transfer Frame Length ​

  • Description: Number of bytes per transfer frame
  • Automation reference: TransferFrameLength
  • Enablement: Coding in [Uncoded, Convolutional]
  • Type: integer

Randomization ​

  • Description: Which randomizer is used
  • Automation reference: Randomization
  • Type: enumeration
IdentifierValueDescription
AbsentAbsent
ShortShort
LongLong (B-5)Long randomizer added in CCSDS 131.0-B-5

Convolutional Code ​

Code Rate ​

  • Description: Code rate (r)
  • Automation reference: ConvolutionalRate
  • Enablement: Coding in [Concatenated, Convolutional]
  • Type: enumeration
IdentifierValueDescription
Rate121/2

Reed-Solomon ​

Error Correction Capability ​

  • Description: Numbers of errors that can be corrected (E)
  • Automation reference: ErrorCorrectionCapability
  • Enablement: Coding in [Concatenated, ReedSolomon]
  • Type: enumeration
IdentifierValueDescription
E88
E1616

Interleaving Depth ​

  • Description: Numbers of RS codewords interleaved to form a CADU (I)
  • Automation reference: InterleavingDepth
  • Range: [1; 8]
  • Enablement: Coding in [Concatenated, ReedSolomon]
  • Type: integer

Virtual Fill Length ​

  • Description: Virtual zeros prepended for each RS codeword (Q)
  • Automation reference: VirtualFill
  • Range: [0; 238]
  • Enablement: Coding in [Concatenated, ReedSolomon]
  • Type: integer

Discard Unfixable ​

  • Description: Discard transfer frames that have unfixable errors.
  • Automation reference: DiscardUnfixable
  • Enablement: Coding in [Concatenated, ReedSolomon]
  • Type: boolean

Turbo Code ​

Nominal Code Rate ​

  • Description: Nominal Code rate (r)
  • Automation reference: TurboRate
  • Enablement: Coding == Turbo
  • Type: enumeration
IdentifierValueDescription
Rate121/2
Rate131/3
Rate141/4
Rate161/6

Information Block Length ​

  • Description: Information Block Length (k, bits)
  • Automation reference: TurboBlockLength
  • Enablement: Coding == Turbo
  • Type: enumeration
IdentifierValueDescription
K17841784
K35683568
K71367136
K89208920

Iterations ​

  • Description: Number of turbo decoding iterations to apply. This number is a fixed number, there is no early termination.
  • Automation reference: TurboIterations
  • Enablement: Coding == Turbo
  • Type: integer

LDPC ​

Code Rate ​

  • Description: Code Rate (r)
  • Automation reference: LDPCCodeRate
  • Enablement: Coding in [LDPC_TMFrames, LDPC_SMTF]
  • Type: enumeration
IdentifierValueDescription
R787/8

LDPC Codeblock Size ​

  • Description: Number of Codewords per output frame (m)
  • Automation reference: LDPCCodeblockSize
  • Range: [1; 8]
  • Enablement: Coding == LDPC_SMTF
  • Type: integer

Iterations ​

  • Description: Number of LDPC decoding iterations to apply. This number is a fixed number, there is no early termination.
  • Automation reference: LDPCIterations
  • Enablement: Coding in [LDPC_TMFrames, LDPC_SMTF]
  • Type: integer

Measurements ​

FixedRS Errors ​

  • Description: MISSING
  • Automation reference: FixedRSErrors
  • Type: integer

UnfixableRS Words ​

  • Description: MISSING
  • Automation reference: UnfixableRSWords
  • Type: integer

Badly SizedRS Inputs ​

  • Description: MISSING
  • Automation reference: BadlySizedRSInputs
  • Type: integer

Detected Packets ​

  • Description: MISSING
  • Automation reference: DetectedPackets
  • Type: integer

Flywheel Acceptances ​

  • Description: Number of packets accepted by flywheel only
  • Automation reference: FlywheelAcceptances
  • Type: integer

Unlock count ​

  • Description: Number of times the flywheel detector lost lock entirely
  • Automation reference: Unlocks
  • Type: integer

Flywheel Lock ​

  • Description: Indicates flywheel lock
  • Automation reference: FlywheelLock
  • Type: boolean

Missed Detections ​

  • Description: Total number of packets where detections were not immediately after the previous frame
  • Automation reference: MissedDetections
  • Type: integer