Has anyone in the Sprinter team considered giving the option of having NTSC compatible sync modes for video? I'm sure with a PLD this would not be difficult to enable. It would make video a lot easier for us USA customers if you had the option. TV's don't have SCART here, just Y/C "S/VIDEO" connectors (and composite of course), and RGB monitors here do not display sync rates below 60Hz either.

Just curious as I haven't assembled my Sprinter yet (just arrived today).



"Did you ever feel everone else are tuxedos and you were just a pair of brown shoes?"

After a little thinking myself, I agreed with the Sprinter team in NOT supporting this or that sync and/or color system.
Not doing so would yield them to the same arena computers like C= Amiga did: You just had to buy this or that modulator, and Amigas (AFAIK, please correct me if I'm wrong) came in boxes that read (in the case of a friend of mine, here in Argentina) "PAL/NTSC VERSION". Now THAT sucks! What if I wanted SECAM video for ANY reason? You would have to buy it in France!

If you just get the signals and build (or get somehow) a modulator for YOUR own area, everyone will be happy. In my country, we have PAL-N wich is different from your NTSC-M in both sync and color standard. What would you in PetersPlus feet do to accomodate all the standards?

In my case, I just dusted off a MC1377 chip based modulator I bought for my PC (ISA at that time), and succeeded on installing it on the Sprinter. Now THAT'S versatile! I tried to get the schematic off it and you can find it in the downloads area (sorry for the coils, though), and it has a NTSC/PAL jumper. Note that, for NTSC, you'll have to change the chroma crystal to a 3.579545 MHz. Luck.


Marcelo.
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Speccy rules, its staff is Sprinter.

Sorry, but we can not agree. Sparky is right. We, developers of Sprinter, should create a maximum comfortable computer. For all customers, from any country.
But you are right too, there are a lot of TV signals standards. Support of all TV standards is too hard technical task. It needs much time. But TV Set is not a best variant of computer monitor. Therefore we hope that finished VGA convertor will be the best solution. It is our main task today. We continue this work.

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PETERS PLUS LTD

Hello Alex!
I have seen your post about Sprinter's output to NTSC screen.
If you want to adapt RGB output to VGA, there are in commerce some devices that do it.
I have found also this russian web site:
http://sterr.narod.ru/tv/tv1.htm I don't understand russian language so I hope that this web site can help you.
If you are only interested in NTSC output there are also:
http://www.preromanbritain.com/gwem/martbean/ataridiy/conv.htm
or
http://products.analog.com/products/info.asp?product=AD724

Alex:
I said what I said because I believed you intended to use TV sets as video monitors for Sprinter. I did not say I agreed with that...

If you plan to "upgrade" video output to use a standard VGA monitor, then the modulation issue goes down the toilet with my full approval. TV standards suck simply because they're intended for the 1940's "state of the art" technology (can you imagine a 1940/1950 TV with 36kHz horizontal sync?).

So, if you can give me a way to connect a VGA monitor to my Sprinter, I will definitely do. WAY better than TV sets with low to mid resolution CRTs.

Thanks

Marcelo.
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Speccy rules, its staff is Sprinter.

"There are a lot of decafeinated brands on the market that are just as tasty as the real thing"...

One thing you have regreted to think about is that the Sprinter is marketed world wide. What a lot of people have neglected to also realize is that the 50Hz refresh frequency, irregardless if it's for TV or even VGA, is completely incompatible with any TV or monitor in the entire North and South Amercian continents. Nobody has ever manufactured a display device to use 50Hz as its refresh frequency.

Also, now a little education in video. A modulator is not going to do anything to change the video coming out of the Sprinter. All a modulator does is put the video signal on an RF carrier. When it's demodulated it is the same video that went into the modulator.

Also, that MC1377 circuit will still not work if the incoming video is still using PAL sync rates. Perhaps if the TV were old enough and had a manual vertical and horizontal hold control a decent black and white picture might be achieved with that circuit. The colorburst is a multiple of the sync frequencies, even if the source clock was with the new crystal. That crystal is there to synchronize the incoming signal with the newly generated chroma signal, which isn;'t possible with the misaligned sync frequencies coming in from the Sprinter.

Adding external circuits to the Sprinter isn't the solution. In fact none of them will have a positive effect, including a VGA converter, as the sync frequencies are still the problem, and nothing here responds to a 50Hz sync, only 60Hz and above.

What is actually a better solution to this is to give the Sprinter the ability to generate a 60Hz compatible set of sync frequencies. This is actually not a difficult thing to do seeing as the Sprinter has a PLD. Simply reprogramming the PLD with the new timing is all that is needed and that's all. Once that is done, using that MC1377 circuit will now work as desired. It would also allow those with RGB monitors to view the Sprinter's video as well.

What would ultimately be the best way to do it is to have VGA sync frequencies for all available resolutions so everyone could view them on an ordinary monitor they may already be using with their PC. Yes, PAL, SECAM, and NTSC sync modes could be an option for absolute Spectrum compatibility or even viewing on a TV, but also giving the same resolution modes (plus more) in the VGA or even SVGA sync range is do-able in PLD software.

Heck, MSX compatibility is also do-able seeing as the MC6845 and MC6847 cores are open source now.

The Sprinter team has done a marvelous job with what they have done, but even they admit improvements can be made. They also know that increasing their market involves increasing the ability of that market to use their product, and not by expressing any sort of "regional arrogance".

The design concept of Sprinter has so much potential of being able to be or even "emulate" many different flavors of Z80 systems of the 80's simply because of its PLD. Why not also have Timex/Sinclair capability as well as Spectrum? What's wrong with MSX capability and even CP/M? Heck, emulating the gameboy and some Sega systems seem like a great idea to me. No, they all can't be installed immediately, but they are not impossible for the Sprinter.

"Did you ever feel everone else are tuxedos and you were just a pair of brown shoes?"

Speaking of Amiga... Nobody's gotten around to testing if an amiga scandoubler (with modified sync signal, i think) works? It wouldn't be the cheapest solution, but certainly the most available one that i know of. The british company Eyetech at www.eyetech.co.uk seems to be selling an interesting external scandoubler for amiga called EZ-VGA-MK2. Their information is a bit fuzzy on the matter though. It is a pity that my amiga scandoubler is an internal model. =(

All a scan doubler will do is give a horizonal rate compatible with VGA, however, the vertical sync will still be 50Hz. 50Hz VGA or even SVGA monitors are not available in the America's. The only RGB monitors with the slightest capability of showing 50Hz refresh rates are the old non-digital types with a manual vertical hold control, and only if its adjustment allowed you to go that low.

Most modern monitors do not go less than 60Hz here. My NEC does 55Hz as its minimum, but since monitors are auto-sync they cannot be forced to view the lower 50Hz rates.

So, TV to VGA (scan doublers) converters will NOT work simply because they do not convert the vertical frequency at all.

Why not just simply give the option of choosing a desired video standard via a PLD update? Fixing the cause not the symptoms seem to be a better approach.

Rich

"Did you ever feel everone else are tuxedos and you were just a pair of brown shoes?"

Funny.. you sure about that? I've never heard of any such problems using amigas and scandoublers. Most monitors won't do 16khz horizontal sync, but the vsync should be okay as far as i know. Always assumed it was anyway. =)

I've now had some people run tests on their monitors too. All seem to handle 50hz quite well. There shouldn't be a difference between PAL and NTSC monitors these days. Perhaps it's just your monitor behaving badly?

Keep in mind WHERE you purchased your monitor.

Now, think about the word "scandoubler" that means "scan line doubler" which means doubling the horizontal frequency and showing each scan line twice at twice the clock rate. This is essentially easy to do with a simple DSP and a small amount of memory in a "scandoubler". Increasing the vertical frequency involves much more sophisticated techniques and much more memory and speed to accomplish this as extra whole frames of display must be displayed where none are generated from the source. Also, typically the number of scan lines can change when the frames per second changes.

With all of that said, no, the scan doublers will only allow viewing on VGA monitors with a low 50Hz refresh ability. Now "listen" carefully, nothing in the North or South American regions have ever been manufactured to display 50Hz video. The only devices that can be "fooled" into displaying such video are the older manually adjusted VGA displays or perhaps the 12 to 15 year old monitors the Amiga or Atari ST used. Those monitors are no longer being manufactured nor sold here in this half of the world.

Incidentally, scan line doublers here only work with 60Hz refresh rates...SURPRISE!

Due to the ease of acquiring newer equipment at very low prices (at least in California) you would be hard pressed to find even "used" equipment shops selling anything older than five years. I'd challenge anyone to be able to find 8 bit ISA PC device sold in the USA anywhere.

Now with all of that explaining behind me. Here comes the main point. This is 2002, and all of the monitors sold in this side of the world do not go lower than VGA standard (60Hz min) for computer monitors, or NTSC standard for composite security monitors or TV monitors. All of these devices now days have automatic sync and are not adjustable to "fool" into displaying a non-standard (for this region) refresh rate. They just turn off. This means, Sony, Nec, Mitsubishi, Samsung, GEM, etc. all have this limitation here. It doesn't matter if they have models in Europe that have this ability. Here, they don't. They have region specific software internal to their design.

Good grief, is this fact so hard to believe, when there has never been a video device here that has ever shown 50Hz based video? All, whether it be TV or computer have always been 60Hz or more. One must also consider that maybe just maybe the FCC might not like the idea of a video display being sold here with PAL capability.

I'm not going to try and hunt down a monitor in some junk shop just so I can display 50Hz video. I'd prefer to just select "PAL" on my TV capture card on my PC. Say what?! If I have that, then why raise this issue? Well, displaying regionally compatible video is best handled in the Sprinter's PLD and not by having to "Mickey Mouse" old crap just to get a decent display out of it (which I have to do just to be able to plug it in my capture card). The Sprinter is a NEW computer and thus should work on equipment no older than at least 5 years.