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OT- 1998 CNC control CRT monitor question regarding input connects...

Milacron

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Siemens 840C to be exact with 14" CRT..... has separate Red, Green and Blue connectors but no Horizontal or Vertical connections. How is this possible ?
 
The green signal becomes, in effect, a composit, black and white style, video signal. The green video is in the positive direction while the sync signals go negative. The Voltage that represents black is the level/line which separates the two.

The two signals, green and sync, are also separated in time just as they are in a B&W video/TV signal. The two signals never occur at the same time. This goes back to the earliest days of TV.

And these two signals are separated in the monitor in the same way they were separated in the original B&W TV sets. The signal is "clamped" to a known Voltage level and anything more negative is sync while anything more positive is the video. Easy-peasy!

The NTSC composit video signal, with all that is included in it, is a masterpiece of electronic magic.


and


That first article says that component video is not to be confused with composit video. While they are different, the combination of green and sync in component video is exactly the same as the way sync is combined in composit video.
 
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>>>The frequency spectrum of the modulated color signal overlaps that of the baseband signal, and separation relies on the fact that frequency components of the baseband signal tend to be near harmonics of the horizontal scanning rate, while the color carrier is selected to be an odd multiple of half the horizontal scanning rate; this produces a modulated color signal that consists mainly of harmonic frequencies that fall between the harmonics in the baseband luma signal, rather than both being in separate continuous frequency bands alongside each other in the frequency domain. The signals may be separated using a comb filter.[5] In other words, the combination of luma and chrominance is indeed a frequency-division technique, but it is much more complex than typical frequency-division multiplexing systems like the one used to multiplex analog radio stations on both the AM and FM bands.<<<
[laughing]
I understand every word in the above paragraph and yet have no idea what it is saying
 
In
The green signal becomes, in effect, a composit, black and white style, video signal. The green video is in the positive direction while the sync signals go negative. The Voltage that represents black is the level/line which separates the two.

The two signals, green and sync, are also separated in time just as they are in a B&W video/TV signal. The two signals never occur at the same time. This goes back to the earliest days of TV.

And these two signals are separated in the monitor in the same way they were separated in the original B&W TV sets. The signal is "clamped" to a known Voltage level and anything more negative is sync while anything more positive is the video. Easy-peasy!
Hmmm.... so then the question becomes does the monitor have to be designed to deal with these composit signals ? In other words if I use a RGB to VGA adapter cable will I get a good display on an LCD monitor ? (assume an older LCD with relatively low horizontal frequency specs)

Using this adapter but simply not using the white and black, H and V wires ? https://www.amazon.com/MEIRIYFA-Adapter-Coaxial-Resolution-Monitor/dp/B09Y1M81NX/ref=sr_1_5?crid=3DEO6K82KS44K&keywords=rgb+to+vga+cables&qid=1663937588&sprefix=rgb+to+vga+cables,aps,74&sr=8-5


Apparently it can be done even with a modern LCD (note wide screen aspect ratio on this example)...below pic is exact same control as mine.

Screen Shot 2022-09-23 at 9.17.04 AM.png
 
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The monitor has to be able to detect sync on green so it will depend on the specs of your particular unit. From what I recall this feature was not hard to find twenty years ago but I don't know if this is still widely implemented. If it can detect sync on green then a passive cable can be used, the H and V cables can be left disconnected.

RT
 








 
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