I could engage in some more speculative thinking.
I could be trying to design a hypothetical analog scheme for modulating color information, that belongs to the Y’UV system for representing colors. But I’d like my system to have as advantage over NTSC, that if the chroma sub-carrier gets phase-shifted, due to inaccuracies with the analog circuits, the result should be a shift in hue, which reverses itself from one TV scan-line to the next, as well as from one frame to the next. Just as viewers don’t normally see dot-crawl when they watch an NTSC-modulated signal on a monochrome receiver, they should also not be able to see the hue-shift, due to analog-circuit issues, with my hypothetical modulation scheme.
Consequently, the receivers for this type of signal should not have a Hue potentiometer.
But I discover a problem in my scheme. The U and V components are to be modulated onto a chroma sub-carrier, using quadrature-modulation, just like NTSC was. And yet, I’ll discover that I can only get the clockwise versus counter-clockwise reversal to take place, if I invert either the U or the V signal-component, but not if I invert both, nor if I just invert the sub-carrier, thereby inverting both U and V:
The problem follows, because every signal which gets modulated onto a sub-carrier, using quadrature-modulation, throws sidebands. Hence, if I was to place the sub-carrier frequency just-beyond the frequencies already being used to encode luminance, I would also need to invert both U and V, by default, to eliminate all the dot-crawl. What can I do?