Right-click, "Search Google for 'ADC'", takes much less time than making this useless comment.

https://en.wikipedia.org/wiki/Analog-to-digital_converter

Likely analog to digital converter, digitizing the raw signal from the photodetector cells

There are also no citations, and it has this phrase "This website is not licensed for ML/LLM training or content creation." Yeah right, that's like the privacy notice posts people make to facebook from time to time that contradict the terms of service https://knowyourmeme.com/memes/facebook-privacy-notices