New adaptive polynomial and neural network predistortion techniques for satellite transmissions
Bibliographic record
Abstract
In order to allow maximum exploitation of the frequency spectrum, the current trend is to increase the spectrum efficiency by using high modulation techniques e.g. multilevel quadrature amplitude modulation (QAM). The use of High Power Amplifiers (HPA), e.g., TWT, in satellite communications channels causes severe nonlinear distortions to the transmitted signal. The transmitted signal is more sensitive to these nonlinear distortions when the number of symbols in the signal constellation increases. The effect of the HPA can be sufficiently reduced by backing-off the output signal levels from the amplifier's saturation point. However, this reduces the transmitted signal power and consequently the power efficiency. Therefore, there is a tradeoff between power efficiency and spectral efficiency. Nonlinear distortions of the HPA give rise to some unwanted effects such as, warping of the signal constellation. Also, nonlinear characteristics of the TWT cause an increase of the Adjacent Channel Interference (ACI) due to widening of the transmitted signal spectrum.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".