NTSC RGB -> VGA

C

Caliban

Guest
If I use an LM1881 IC to strip the H and V sync off of an EIA RS170 sync
on green video signal (NTSC?), could I then apply the RGB video lines
and sync signals to a standard LCD or VGA computer monitor?

The RGB video signals are 0.7V analogue, 16kHz Horiz, 720 x 540
dots/lines resolution.

The other problem is finding a source of 12 to 13" Monitors, Google has
turned up a few overseas but none in Aus.
 
Caliban wrote:
If I use an LM1881 IC to strip the H and V sync off of an EIA RS170 sync
on green video signal (NTSC?), could I then apply the RGB video lines
and sync signals to a standard LCD or VGA computer monitor?

The RGB video signals are 0.7V analogue, 16kHz Horiz, 720 x 540
dots/lines resolution.

The other problem is finding a source of 12 to 13" Monitors, Google has
turned up a few overseas but none in Aus.
Click to expand...

Also looking at 15" and 17" monitor specs I notice they have a minimum
30kHz horizontal scan, where as my signal is 15kHz. Any ideas?
 
"Caliban" <null@void.com> wrote in message
news:d0rspb$crc$1@otis.netspace.net.au...
Also looking at 15" and 17" monitor specs I notice they have a minimum
30kHz horizontal scan, where as my signal is 15kHz. Any ideas?
Click to expand...
I don't think you'll find any multisync monitors made in the last ten years
that go down to 15kHz, except those already designed for TV use.

MrT.
 
On Fri, 11 Mar 2005 21:44:17 +1100, Caliban <null@void.com> wrote:

Caliban wrote:
If I use an LM1881 IC to strip the H and V sync off of an EIA RS170 sync
on green video signal (NTSC?), could I then apply the RGB video lines
and sync signals to a standard LCD or VGA computer monitor?

The RGB video signals are 0.7V analogue, 16kHz Horiz, 720 x 540
dots/lines resolution.

The other problem is finding a source of 12 to 13" Monitors, Google has
turned up a few overseas but none in Aus.


Also looking at 15" and 17" monitor specs I notice they have a minimum
30kHz horizontal scan, where as my signal is 15kHz. Any ideas?
Click to expand...
Is used gear ok? how about an 80's analog computer monitor (eg
commodore 1084). Shouldn't be hard to find one on ebay.

If you don't mind a not-so-perfect image you could simply use a TV as
a monitor, just find one with a SCART socket. The only problem I can
see here is that TVs with SCART don't usualy come any smaller than
19". Though I've noticed that some small TVs (esp from sharp, samsung
and lg) use a signal processing IC designed to accommodate a SCART
connector, so modifying the TV for an RGB input is trivial (3
terminating resistors and 3 coupling caps).
 
"Caliban" <null@void.com> wrote in message
news:d0rqpm$c2t$1@otis.netspace.net.au...
If I use an LM1881 IC to strip the H and V sync off of an EIA RS170 sync
on green video signal (NTSC?), could I then apply the RGB video lines and
sync signals to a standard LCD or VGA computer monitor?

The RGB video signals are 0.7V analogue, 16kHz Horiz, 720 x 540 dots/lines
resolution.
Click to expand...

TOO SLOW for a standard VGA CRT !
The CRT's expect at least 50Hz vertical and 30kHz horizontal.

So you are hitting it with 16kHz and 30Hz..



Perhaps an LCD can do it - they often have tuner attachements optional.



The other problem is finding a source of 12 to 13" Monitors, Google has
turned up a few overseas but none in Aus.
yeah its hard to find a small CRT.
Click to expand...

easy to find small TV's, what are you doing ?? why not convert current
signal to Composite ??
 
Thanks for the replies, I did a bit of Googling and the info on trying
to get old video arcade games to connect to TVs and monitors is pretty
much what you have covered.

It's a replacement for a few very old process control monitors on a
ship. The sensors and processing are ok but the monitors are
unserviceable. Apparently replacements were not available.

But I have found a company in the UK that make exactly what I'm after (
http://www.kme.co.uk/ ) - it just comes down to the price now

If they are too expensive I'll try RGB -> composite conversion using
something like the Motorola MC1377 and send it to an LCD or CRT TV
monitor and see what the quality is like.
 
Fred Ferd wrote:
....
easy to find small TV's, what are you doing ?? why not convert current
signal to Composite ??
Click to expand...
Yeah it looks like that's what I'll have to do.
See my post above.
 
"Caliban" <null@void.com> wrote in message
news:d0s20e$eft$1@otis.netspace.net.au...
Thanks for the replies, I did a bit of Googling and the info on trying to
get old video arcade games to connect to TVs and monitors is pretty much
what you have covered.

It's a replacement for a few very old process control monitors on a ship.
The sensors and processing are ok but the monitors are unserviceable.
Apparently replacements were not available.

But I have found a company in the UK that make exactly what I'm after (
http://www.kme.co.uk/ ) - it just comes down to the price now

If they are too expensive I'll try RGB -> composite conversion using
something like the Motorola MC1377 and send it to an LCD or CRT TV monitor
and see what the quality is like.
Click to expand...

yeah, well for a small computer accurate display you can always try
australian electronics catalogues like "farnell" for "price".

they'll have small CRT's of some sort.

TV's look a bit unprofesional, with their tuning buttons and speakers..
 
Fred Ferd wrote:
"Caliban" <null@void.com> wrote in message
news:d0s20e$eft$1@otis.netspace.net.au...

Thanks for the replies, I did a bit of Googling and the info on trying to
get old video arcade games to connect to TVs and monitors is pretty much
what you have covered.

It's a replacement for a few very old process control monitors on a ship.
The sensors and processing are ok but the monitors are unserviceable.
Apparently replacements were not available.

But I have found a company in the UK that make exactly what I'm after (
http://www.kme.co.uk/ ) - it just comes down to the price now

If they are too expensive I'll try RGB -> composite conversion using
something like the Motorola MC1377 and send it to an LCD or CRT TV monitor
and see what the quality is like.



yeah, well for a small computer accurate display you can always try
australian electronics catalogues like "farnell" for "price".

they'll have small CRT's of some sort.

TV's look a bit unprofesional, with their tuning buttons and speakers..
Click to expand...
buy a modern TV, with no buttons other than on/off. Just dont lose the
remote control :)

Cheers
Terry
 
On Fri, 11 Mar 2005 23:13:24 +1100, Caliban <null@void.com> wrote:

Thanks for the replies, I did a bit of Googling and the info on trying
to get old video arcade games to connect to TVs and monitors is pretty
much what you have covered.

It's a replacement for a few very old process control monitors on a
ship. The sensors and processing are ok but the monitors are
unserviceable. Apparently replacements were not available.

But I have found a company in the UK that make exactly what I'm after (
http://www.kme.co.uk/ ) - it just comes down to the price now

If they are too expensive I'll try RGB -> composite conversion using
something like the Motorola MC1377 and send it to an LCD or CRT TV
monitor and see what the quality is like.
Click to expand...
the mc1377s are pretty crappy...there was one of them in my old amiga
modulator - 80 col text was unreadable

maybe the newer encoder chips are better...
if you could live without colour you could just sum the red, green,
blue and sync with a fast op-amp to make monochrome composite

Give the TV/SCART modification a try - it's a bit easier that building
a CVBS encoder circuit. All the LG tvs have a spot for a SCART socket
(I just had a look through my archive of LG circuits and they all have
this) on the PCB (under the AV sockets). It's simply a matter of
removing the AV socket block, putting in a scart socket, installing
the missing termination resistors and a few wire links.

I'm pretty sure the samsung ones are like this too but i've got no
circuits for 14" samsung tvs so I can't be certain.

pulling pin 8 of the scart to 12v and pin 16 to 2v will force the TV
into RGB mode and act as a monitor. The Sync goes into the video input
- 0.3vp-p/75R.
 
"Caliban" <null@void.com> wrote in message
news:d0rqpm$c2t$1@otis.netspace.net.au...
If I use an LM1881 IC to strip the H and V sync off of an EIA RS170 sync
on green video signal (NTSC?), could I then apply the RGB video lines and
sync signals to a standard LCD or VGA computer monitor?

The RGB video signals are 0.7V analogue, 16kHz Horiz, 720 x 540 dots/lines
resolution.

The other problem is finding a source of 12 to 13" Monitors, Google has
turned up a few overseas but none in Aus.
Click to expand...
What about getting a US NTSC lcd display ?
Lots of industrial types.

Earthlcd.com carries lot but will rip you big time on shipping
(plus java based website)
They have 11.3 and 12.1 inch lcds
http://store.earthlcd.com/s.nl/c.318770/sc.7/category.16/.f

Will need to get power supplies as well
May need to get a mositure proof casing

Going to be pricey unless you can buy second hand.

Alex
 
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