Scandoubler schematics

[amiga_3k]

So basically, now Clone-A is functioning, Individual Computers should now re-implement Amber? ;-)

[Jeff]

Has anyone done an english translation of the german pdf file yet? Failing that, is there a tool online that will do it?  This looks like a great project, but I can't read the docs.

Thanks, Jeff

[motorollin]

Does an Amber card work on an A4000, or only an A3000?

--
moto

[whiteb]

It looks good, but given that the amber chips are out of production I would not recommending all the A3000's in existance be butchered for the chips.

[Jeff]

I agree, however I already have enough spare parts around without hurting any good 3000's to build 1 board:-)  So I may attempt it.

Jeff

[skurk]

While we are slightly off-topic:  Aren't there any VGA adapters for any game consoles that may be modified to fit the Amiga RGB port?

Playstation, Gamecube, Dreamcast, SNES..?

[countzero]

yes, there are. the Xrgb and the CM-345S are the first to spring to mind. They equally (or more) expensive as the scandoublers.

[motorollin]

Are we saying that there are no chips in existence which can convert the video signals from the Video Slot to VGA?

--
moto

[Zac67]

When fiddling with devices not intended for the Amiga, you'd have to distinguish between scan doublers and flicker fixers.

Simple scan doublers just buffer one 15 kHz line and output it twice at 31 kHz to make it VGA compatible. That's not what you want because you wouldn't get rid if interlace flicker.

Flicker fixers buffer a complete interlaced field and output the previous field in combination with the current one, thus producing a progressive output. OTOH, what you see is partially (the buffered field) already 20 ms older than the rest, which leads to ugly comb/shearing effects.

Wikipedia has a very good article on this.

[LaserBack]

All Amiga' scandoublers have issues here and there except the one built it on the A3000 that works perfect cause it works through the amber chip that was specially designed for the amiga screenmodes

Other scandoublers or chips will work but with issues on the AGA palette or interlacing problems

I think that it's a waste of time try to build a home made scandoubler cause it will not work fine

That A2320 maybe works perfect even on AGA screens cause was designed with 2 ambers chips.....and is the only one that I wish built

but two A3000 required to built one of these


So....the best solution is a new LCD TV


bye
 

[Jose]

So how does the 2320 eliminate the comb effect ? Does it manage to do it already in A3000's using interlaced screens  at 15khz (i.e. 640x512)?

[Zac67]

Jose wrote:
So how does the 2320 eliminate the comb effect ?

It doesn't. Doesn't even try. Deinterlace interpolation with early 90's technology was out of the question.

[Jose]

@Zac67

Ahh, I asked that cause some of you guys on this thread seemed to imply that it would be the perfect solution.. ( the A2320)

[amiga_3k]

@Jose:

The scandoubler/flickerfixer actually performed brilliant (especially when using a little slowish CRT monitor) in the Amiga 3000. The 'combing' effect was never a problem for me as the SD/FF was only flickerfixing while using Workbench (can't remember a single game with high-speed grafics in interlaced mode). Only the standard mouse pointer had to be replaced by some hi-res mouse hack. So, for your average dtp work, playing about with PPaint and stuff like that is was really usable.

[Zac67]

An A2320 / Amber board is probably the best solution you can get; only drawback with the original design is the limitation to 12 bit.

As to deinterlacing effects: for a computer's video output there's no definite solution to the problem. For a video (=camera) type signal there are some interpolation methods that work quite well - but a computer's output is very arbitrary and not predictable. E.g. fonts have to be reproduced very accurately to be easily readable. I doubt if there's a 'perfect' solution to this.

There are two workarounds for this problem:
- limit screen updates to 25/30 Hz - when both fields fit perfectly there will be no artifacts
- use a video card and get rid of this problem alltogether

OTOH what Amiga_3k writes is true: it's no real problem.

[amigite]

I can't understand how anyone who owns the rights to this Amiga computer can go on doing business without addressing the video resolution problem.  They leave it up to 3rd. parties but no one is interested in it.

Amiga needs a scandoubler, Flicker Fixer. A real one that works with all of the different hardware.  We need a way of using modern resolution monitors.  The 15 Khz resolution made for television was a different kind of idea at the time.  But now its really getting old.  We feel it because our monitors are really starting to show their age.  We need a solution.

Software hut www.softhut.com had a solution called Toastscan.  But they are not being made anymore.  Software hut was trying to find someone to build them a new device to sell.  Maybe you can contact them and they will turn you on to some business, if you have the talent required to build the thing.

There were some devices, made to convert RGB to VGA for Game consoles. Check this one out- http://www.tiptonium.com/videogames/reviews/other/XRGB2.htm

How about this one,

http://www.cypuk.com/cyp_techpage.php?product=228&&parent=0

or this one,

http://www.ihse.de/english/238-3f.htm

Then there is something called scart over in Europe.  We don't see much of it here in the US, but some have reportedly had success using the input of a scart connector on new TV sets.  Not quite SVGA resolution, but as good as some of our old monitors. No solution to flicker at some resolutions.

Amiga users were using them to circumvent the signal.  None did the complete job all the time to my knowledge.  I hope someone can prove me wrong and give us a solution.