TI-99/4A Comments

From: Philip.Belben_at_powertech.co.uk <(Philip.Belben_at_powertech.co.uk)>
Date: Fri Jun 13 16:03:05 1997

> Aha! YUV is something I recognize now. I believe this is what broadcast
> professionals call component video. (Let's see if I'll be right one out of
> two.)
>
> > The signals are transmitted this way in broadcast TV to ensure
> > compatibility between colour and BW tellies. They are also the signals
> > that would normally be sent to a TV (UHF or VHF) modulator from the
> > computer, hence their presence on the video connector.
>
> Hmmm... any modulator I've ever worked on had a composite input. Is this
> maybe more common in European systems?

Hmm. I'm getting out of my depth at this point. I've not dealt in
detail with many colour modulators but I recall the Sinclair Spectrum
had YUV as opposed to RGB on its expansion port.

The computer obviously uses RGB internally (although I don't see why one
couldn't design a machine to do YUV instead!) and it has to be converted
to YUV at some stage in the modulation process. My guess (no evidence
to back this up) is that the more expensive modulators - the ones one is
likely to be able to buy for one's own projects - accept composite, but
many mass-producing manufacturers got away with a cheaper modulator by
putting the conversion in the (custom) chip in the video circuitry.

Philip.
Received on Fri Jun 13 1997 - 16:03:05 BST