Re: Plasma, LCD, DLP which way to go


leaky wrote:
<snip>
Reply
First I was refering to consumer vcrs not pro equipment which
are more costly and designed for longer life. A bad drum bearing does
cause the rf envelope failure. On the dlp mirror issue maybe you can
explain where the light goes as the mirror changes it's reflection
angle. If the mirror is directed at the lens and then it's not
directed at the lens, how did it get there. Did they turn off the
light while the mirror shifts? No, afraid not. I suspect that it may
be you, that does not understand how the technology works. I am pretty
sure I understand the technology well enough to be able to design a dlp
but would love to hear comments to the contrary. Take a good close
look at your dlp and see if white areas don't simmer and flicker.
Looks kind of like video noise.
Leaky

OK. I put up a DVD of 75% SMPTE color bars through the DVI port and did
a freeze on the DVD. If your claim is correct, shouldn't I be seeing
flicker / shimmer in the image? IF there is a slight trace, (and it is
so subtle nearly no one including me sees it) I suspect that could as
easily be slight variations between the multiple RGB segments of the
color wheel or a flutter of the 4000+hr lamp.

What I'm surprised you DIDN'T mention is the PWM math errors that show
up in a continuous color gradient. It is the same as a monotonicity
error in a DAC. This type of error also shows up in the Panasonic
plasma displays we have at work. It also shows up in flat LCD displays.

BTW, many of the VCRs are VHS decks which use the same drums as
consumer machines. I'm not particularly worried about the color wheel.

As for the 'Looks kind of like video noise', I suspect what you're
seeing IS video noise. It is VERY difficult to avoid. But if you design
DLPs, you know that already.

GG

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