On 2011 Feb 8, at 7:16 AM, Richard wrote:
Philip Belben <philip at axeside.co.uk>
writes:
There is
no grayscale in a storage tube monitor. There's charge
stored on the tube, or there isn't.
Sorry, I wasn't clear. I didn't mean greyscale stored on the tube. I
meant, can it read out how much of a pixel is covered by drawn lines
and
interpret that as greyscale?
Well, the whole process in the original equipment is analog. You're
not going to see aliasing due to discrete sampling, because there
isn't any. You will see aliasing due to the bandwidth of the analog
signals, but there isn't anything changing so fast that its outside
the bandwidth of the circuitry.
For that matter, how big are the pixels?
There aren't any pixels.
I know what you mean here, so not to argue your point about the analog
process in the system under discussion, but I would like to add an
historical footnote: even analog raster-scan systems were characterised
in terms of "picture elements" going back to the very early days of TV.
A book I have here ("Principles of Television Engineering" / Fink /
McGraw-Hill/ 1940) presents the scientific and engineering background
to TV systems at the time. The phrase "picture element" is used
throughout. The then-current transmission standard was characterised as
441 lines by 400-600 picture elements per line, "that 3,000,000 to
6,000,000 elements must be sent in a second", etc. The characteristics
of other mediums such as photographs are also presented in terms of
picture elements.
When "picture element" started getting abbreviated to "pixel", I
don't
know.