All due respect Charles, but this seems like click bait. No baseline of the noise on the switch over ethernet cable vs the optical. Using cheap converter with switching power supply on the ethernet cable output. And introducing almost a half a volt of noise and finding an issue at one megaherz? That noise could be on the electrical ground on that bench. That's not a scientific experiment and they almost say as much on their blog.
..."But what if we start adding noise? We inject 400 mv of white noise (up to 60 MHz) through the Rigol function generator. That’s a lot and quite strong. So take this with a grain of salt."...
https://www.alpha-audio.net/background/a-few-brief-trials-of-fiber-optic-converters/Edit: spelling
