Someone above was discussing what would occur if you transcoded component from the RGB signal produced from this mod. Chroma subsampling would take place when you go from RGB to YPrBR colorspace.
True, most component signals are filtered to reduce chroma bandwidth. There's no interconnect reason for that however. The Pb and Pr cables are the same as the Y cable and full bandwidth chroma is legal in analog component video. Once you go to S-Video or composite then bandwidth reduction is necessary.
From what I can see of the photos of Tim's circuit he's got a bunch of resistors presumably to do weighting and scaling of the RGB signals and dual Op Amps to do a subtraction for each chroma signal. He's got video driver caps on each signal and a single power smoothing cap. I don't see any low pass filters on Pb and Pr. I think they are likely full bandwidth. So it's really up to your TV. It may filter component at the input or it may not depending on how it's built.
However RGB is not immune to all this. The RGB signal is almost always converted to YPbPr and back even on analog sets. The YPbPr space is a much easier space for signal processing, especially in analog. If brightness, contrast, color and tint effect your RGB input your set has almost certainly converted to YPbPr for that processing. If your set chroma filters YPbPr it probably internally chroma filters the RGB to YPbPr conversion too.
Even if chroma filtering occurs you are unlikely to tell. DVDs and Blu-rays halve chroma horizontally and vertically and they look great. At most a low pass filter on component will halve the horizontal chroma but keep the full vertical chroma resolution.
Ultimately we're talking about an Atari here with 160x192 pixels and a 128 color palette. None of the subtleties of colorspace conversion or chroma filtering should be visible at all.
Edited by collinp, Wed Aug 12, 2015 3:55 AM.