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#21
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Monitor cable
In message ,
Lostgallifreyan writes: "J. P. Gilliver (John)" wrote in : I didn't mean vertical cables, I meant you get ringing on the images where there's a vertical line in the image! (At least, more noticeable.) Oh. Ok. That difference in each axis might be related to the scan frequencies, but it might also be illusion. I find that a 1px line looks sharp horizontally, but blurred vertically. If I lean sideways enough to make my head horizontal, the acreen's horizontal line looks blurred, and its vertical one looks sharp. This is true for CRT's and LCD's. I'm surprised - I suspect the latter is from blood rushing to your - er - eyes or something! Ringing and ghosting on vertical lines is familiar to anyone from analogue TV days: if the TV signal arrived at your aerial by a direct path and also bouncing off a nearby building or hill, you got the same feature repeated a few microseconds apart (ghosting - you'd get similar from reflections at cable joints, shorter duration but we're usually talking faster scanning so the effect is similar); sharp edges (strong vertical lines) can also cause damped oscillations in the circuitry (ringing). Both of these will show as horizontal effects, because the raster making up the image is scanned horizontally. To get vertical ghosts/rings, the echo would have to be a lot longer (several line periods), and while not unknown, it's a lot rarer. Such signals can contribute to a general fuzziness if the individual ghosts/rings are not individually distinguishable but mushed together, but that still tends to manifest as a horizontal effect only. The effect should be independent of whether it's a CRT or not, though I have the feeling that it's less noticeable on non-CRT displays, possibly because of the inherent quantisation (in the time domain) they have. -- J. P. Gilliver. UMRA: 1960/1985 MB++G.5AL-IS-P--Ch++(p)Ar@T0H+Sh0!:`)DNAf I can live with doubt, and uncertainty, and not knowing. I think it's much more *interesting* to live not knowing than to have answers which might be wrong. - Richard Feynman, in 1981 Horizon interview |
#22
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"J. P. Gilliver (John)" wrote in
: Does the rewritten version deliberately have the blank lines in? I think it deliberately doesn't have them. At least, this time I didn't see any. |
#23
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Monitor cable
"J. P. Gilliver (John)" wrote in
: Oh. Ok. That difference in each axis might be related to the scan frequencies, but it might also be illusion. I find that a 1px line looks sharp horizontally, but blurred vertically. If I lean sideways enough to make my head horizontal, the acreen's horizontal line looks blurred, and its vertical one looks sharp. This is true for CRT's and LCD's. I'm surprised - I suspect the latter is from blood rushing to your - er - eyes or something! Nope. Is real enough, something to do with how we process info by eye. It's not much harder to pick up the VDU and turn it 90° so I did it to confirm. I think it may be purely due to our eyes being set apart on horizontal axis and not vertical. I understand ghosting (and surface wave propagation vs direct in RF, etc), I just mention that illusion because when looking for any fine detail that might differ between axes, this is a useful trick. Anything that survives it is in the hardware, and not us. I find it important when doing anything at 1px resolution. Digital image magnifiers only work at design time, but to see the effects of perception on un-zoomed detail, it pays to check it that way. Small aperture-grille moire patterns and ghosting can't be zoomed anyway.. Not that we need think about aperture grilles much anymore. |
#24
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"J. P. Gilliver (John)" wrote in
: The effect should be independent of whether it's a CRT or not, though I have the feeling that it's less noticeable on non-CRT displays, possibly because of the inherent quantisation (in the time domain) they have. That seems right. I've seen it on an LCD but that was when I was testing a thin cable, knowing to expect poor quality. It may even help to fool eyes and brains into not seeing the pixel grid pattern. I don't have that problem anyway, maybe because I'm too long-sighted now. I get my subtle blurring for free. |
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#28
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In message , MotoFox
confucius-say@enlightenment!to!him!lead!it!for!bangpath!foll ow!man!wise. UUCP writes: And it came to pass that Lostgallifreyan delivered the following message unto the people, saying~ (You lost me with all the hex stuff......) You could also deliberately aim one short of standard column width; 71 instead of 72. I'll try that. The "standard" wrap width Pan uses is 74 columns, whereas Thunderbird (probably other Mozilli as well) uses 72. Hmm. I've never heard of anything using 74 before. I've heard that 72 was chosen to allow four levels of quoting (assuming " ") on 80-column terminals, though 74 would allow three levels, so is arguably just as valid, I just haven't heard of it. -- _ _ ______________ ___________ __ / \/ \/ __ _ _ __ \/ __ __ \/ / / /\/\ /_/ // // /_/ / __// /_/ /\ \ /_/ \____//_/ \______/ \____//_/\_\ !i84w!exit210!304senye!motofox As other[s?] have pointed out, (a) some of your lines are short (but are still being doubled), (b) it is only happening to your signature (below - but, I notice, not including - the "-- " line). -- J. P. Gilliver. UMRA: 1960/1985 MB++G.5AL-IS-P--Ch++(p)Ar@T0H+Sh0!:`)DNAf Advertising is legalized lying. - H.G. Wells |
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