Terminal timing synchronisation in DVB‐RCS systems using on‐board NCR generation
Bibliographic record
Abstract
In DVB‐RCS systems, Return Channel Satellite Terminals (RCST) receive a stream of Network Clock Reference (NCR) packets from a central Hub station to regenerate their internal clocks and aid network synchronisation. Where the NCR is generated at a ground Hub station the delays between Hub and satellite (and the reverse path) must be measured; an allowance for the measurement error is made in the guard time. The bandwidth efficiency gains of locating the NCR clock on‐board the satellite are evaluated: for high transmission rates the gain may be worthwhile whereas for lower rates a negligible benefit exists. In some applications, on‐board processing may be used to switch packets on the forward link (for routing to different beams). With an on‐ground NCR source, the satellite switching most likely results in NCR delay variance (jumps) beyond acceptable limits for correct RCST frequency regeneration. An on‐board NCR clock aids a system architecture that encompasses forward link switching and can be justified in these circumstances.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".