A 5GS/s 4-bit time-based single-channel CMOS ADC for radio astronomy
Bibliographic record
Abstract
A 4-bit 65nm time-based analog-to-digital converter (ADC) targeting the next-generation Square Kilometre Array (SKA) is presented. This ADC is composed of an analog voltage-to-time converter (VTC) front end and a digital time-to-digital converter (TDC) back end. The two components can be physically separated to minimize the impact of digital noise from the ADC on high-gain, high-sensitivity receiver chains common in radio telescopes. At a sampling rate of 5 GS/s the ADC consumes 35 mW from a 1 V supply. After calibration, the ADC achieves a peak SNDR of 22.9 dB, SFDR of 34.0 dB and ENOB of 3.5. At the ERBW of 2100 MHz, SNDR is 18.4 dB, SFDR is 22.3 dB and ENOB is 2.8. The resulting worst-case figure of merit is 1.0 pJ/conversion. This is the highest reported sampling rate for a time-based ADC to date.
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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 | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.007 | 0.003 |
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".