Edit: The RGB picture for comparison.
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Here is my first attempt for a CRT TV displaying a PAL video signal. The very
first version here basically implements the core PAL signal modulation/
demodulation process via two dual-sideband-suppressed-carriers, arranged in
quadrature as the engineers would say, with some special luminance and chroma
filtering applied to the Yuv color signal.
It's just a start, many things need to be done. For example, currently there
is no phase alternation (PAL :<=> Phase Alternate Line). Hence, the PAL signal
here is 'perfectly' demodulated, i.e. a perfect local oscillator with no phase
drift whatsoever is at the works, which wasn't the case back then in many of
the old TVs. I will address this point while implementing NTSC which basically
requires me to not display the same color twice on each scanline. xD Yeah, a
classic one.
Many common oscillators do produce phase errors leading to
slight color drifts on a scanline. Hence, a picture on an old NTSC TV shows
some graded color shading and there isn't much help of the system to counter
act it. Even the so-called Color Burst (sync pulse, or pilot tone (stereo
radio)) wasn't enough. For example, the right side of such an TV may slightly
be covered in a red tint (depending on the oscillator drift). But you know
what? PAL essentially has the same issue! So you can counter act the argument
now.
Since for one scanline the u (Yuv, uv croma information of the signal)
oscillator phase is 90 degrees ahead of v. Yet for the next scanline the
situation is reversed and u trails 90 degrees behind and so on. However, this
doesn't make the problem go away all of a sudden but it ensures that any
oscillator drift has an opposite effect on alternating scanlines. So where is
the trick? Well, you won't see the color drift while sitting on the other side
of the room! Your eyes basically blend the phase error away (within certain
limits, of course). That was the trick with PAL in yielding better color. But
the NTSC guys had a striking advantage; 60Hz (30fps even/odd, instead of 50Hz
PAL with 25fps even/odd) which made a difference in some games (fast games,
racing games). Anyhow, one can build a 60Hz PAL signal as well by lowering the
scanlines, which could be done by the PS2 (EU) for example.
Yet there is much more to do and I could write odds and ends about it, but I'm
not sure whether many here are interested in technical stuff even if they can
understand all of what's written. Anyhow, everything here will result in some
pictures, luckily.
Btw; There is also a ringing effect implemented you won't recognize from the
still image shown.
Many cool things to come!