Component Out - How easy is it to accomplish?

PCE isn't really where composite shows its uses best. Most composite-related effects are found on Genesis, SNES has a few as well.

 

Well if you're talking about the effects composite produces like checkerboard or vertical lines on the RGB pictures, yes Im aware that on Genesis for example (and master system) it can cause a lot of these. But I've seen similar effects on a premodded DUO-R Ι got recently that used composite instead of Sync. Checkerboard pattens were obvious.

If you want the best RGB picture possibe, always use Sync instead of the messy composite.

 

Maybe your TV can't. This isn't a limitation of composite video. With a good signal you can even see pixel edges through RF modulation... PCE video for the most part has a bandwidth of 2.68 MHz, and just about every TV has a luma bandwidth of over 3 MHz. Since luma is more influential by far to the PQ, and luma isn't filtered to below the PCE's bandwidth, luma directly follows the PCE's pixel clock the same as RGB. Technically unfiltered computer pixels have very high frequency content which allows very sharp pixel boundaries, composite loses a lot of this, S-video retains most of it. With RGB it's limited by the bandwidth of your transmission line and display. For PCE it doesn't really matter, you can still see the edges of many pixels.

The place where composite mainly fails in games is because often the I component of chroma dips down into luma causing artifacts. I'm not sure exactly how the PCE filters chroma, but it's possible there is very little interference at all at the cost of color bandwidth, basically only in patterns of alternating black and white pixels. By using S-video you are completely free of the artifacts, making the only clarity issues the low chroma bandwidth which your eyes are not supposed to be able to discern.

Those pictures? Yes, more or less. BTW, you should use less JPEG compression when showing off your PQ

Your opinion is somewhat misinformed, the sync in composite video is identical to composite sync, it's essentially a digital signal. Is composite sync more pure? Yes, because composite video has is composite sync with some other stuff at higher frequencies. Does it make any bit of difference? Not really, composite video is more than adequate at carrying the low frequency sync signal to achieve a stable raster... The source of sync has absolutely nothing to do with picture quality, the only signals responsible for that are R, G and B.

That said I agree that regular composite sync is better, because many displays such as arcade monitors are not equipped to handle composite video.

No you don't need to amplify sync. You need to provide the display with the desired level however, and TVs desire ~0.3 V into 75 ohms. This can be done from the logic level sync output which on the PCE will be around 5V... With a few resistors you can attenuate 5V to 0.6 V with 75 ohm output which will divide to 0.3V with the display's 75 ohm termination resistor. This is the proper way to do it, and if you're concerned about current or ESD you can buffer the signal. Since termination is hardly an issue on a slow sync signal you could even have a high impedance sync output without problems, this requires only a single resistor and will definitely fall within the current sourcing capabilities of any logic chip.

Technically your amplifiers aren't really amplifiers in the normal sense (voltage gain) at all, they're current amplifiers (lossy voltage buffers). They are achieving approximately the desired signal level by brute force, meaning they take 4x or more current to deliver the same signal to the TV, without the benefits of termination. It only looks adequate because the PCE has such low bandwidth video.

 

In theory composite video isn't too bad for what it is. In real-world usage scenarios, it often turns out that way. Some consoles and TVs have bad encoding or decoding. Either may display artifacts.

Using RGB a console already has, is an easier way to get around said artifacts than trying to replace the console's encoder and/or TV's decoder. And less expensive than buying a high end XRGB type device.

 

Any suggestion to amplify my composite signal? Just direct wiring you can´t get any normal image on CRT.

 

Truth be told your CRT is probably applying digital filters too, not just on composite for the 3D combfilter but possibly also on your RGB in order for it to provide a stable menu overlay. Can you get a menu overlay in RGB mode? If so it probably is digitizing the picture (albeit with low latency).

I'm under the impression that almost all mid-high end TVs from the 90s onwards actually sample their video to operate on it in the digital domain. They sample it at 13.5 MHz http://en.wikipedia.org/wiki/Rec._601
If your TV does this to RGB you get little of RGB's benefits over S-video because the bandwidth is limited to below 6.75 MHz (DVD quality) whereas most truely analog arcade RGB monitors will have bandwidths of 15 MHz and up. Now if you couple game RGB that's properly terminated to a 60 MHz CRT you'd see true sharpness and the actual benefits of RGB. You can actually do this easily at home with a nice VGA monitor and custom emulator...

This is why I can't take RGB nuts too seriously, everyone thinks their setup is so great but if they understood what was really happening to their signals through their mods and encoder/transcoder/upscanner/scanline inserter etc signal chains some heads would explode.

Composite video is great, it allowed cable TV to be possible. It isn't however great for computers/games, but for the most part it's sufficient. It would have been cool if all consoles only output RGB and everyone made optional universal RGB RF/composite/S-video/YPbPr modulators in order for consoles to be cheaper and all provide RGB, but things didn't turn out like that.

Uhh? You mean the original white RF PCE? The best solution would be to recreate the composite video amplifier from the CoreGrafx but that's kind of complicated. If you're talking about using composite output from a CoreGrafx, IFU, DUO etc then you have a bad composite video input.

 

The end justifies the means. Video display at the stage of visible light from the CRT's front glass is what matters. Not that it's "correct" from an electric engineering view point.
Most home users seeking maximum quality, intend to improve their game experience, rather than write science reports on the signal chain.

 

Exactly!!! At the end of the day, results on the screen is what matters and by my observations, RGB is by far the best option to get the best results. With RGB I get a clear colourful and normal looking picture having the same colors as an emulator and thats what everybody wants from a 20+ year old console. Composite may be providing a relatively good picture compared to RF but according to my observations on more than one tv set, it just doesn't hold a candle to RGB.
And probably this is why everyone on www.pcenginefx.com which is the best place to get technical info on the PCE, considers the amplifier I used, the best solution to get an excellent RGB picture out of this console. Afterall as I said, the result is what counts.

Digital filters applied by LCD sets make the graphics look unreal and not at all as they were meant to look on the glass crt screen. So whatever "digital filter" a crt is appliying (if any), the outcome on an LCD is weird and on a CRT its not. Again, only results matter most and not theory.

Compare composite and RGB on an LCD and they might look almost identical after all the digital filtering. Truth is, they aren't, compare on a crt 4:3 and you'll see the difference with your own eyes.

Sync signal (or composite sync if you preffer it) needs amplification, many monitors or RGB capable european tv sets, have trouble displaying a stable picture if you use sync straight out of the PCE's chip pin.
My set can display OK with or without amplification on sync but I've noticed small differences in clarity and colours so I go with amplifying the Sync which is also what is recomended on the www.pcenginefx.com forum.

 

Well that doesn't mean you want to just toss any old idea together.

My crt's component input gets screen rolling(!) if Sega Genesis video transcoded from RGB gets too strong or whatever. Most noticeable in Sonic 3, especially large areas of white like its file select screen and the Ice Cap Zone snowboard intro.

 

Neither a too strong nor a too weak signal is good. This is why I'm always using the amplifier I gave a link before in all my modifications for RGB. Actually the schematics for it are taken from the PCEngine 1988 Japanese Book (there is a name for it in Japanese but I can't type it, sorry). This amp is supposed to be specificaly designed to give the best possible RGB out on a PCEngine, taking the appropriate signals either from the chip's pins or from the expansion port.

 

yeah IIRC in the part that the transistor legend is pasted over it actually had the NEC logo and the page number from said book...

 

What's "correct" isn't an opinion, it's a measurable fact. TV's are designed and calibrated to accept very specific signals. When you send a TV bad video and are satisfied with the outcome, it's because either you have low or peculiar standards or the TV is extremely forgiving of bad video signals. If you try the same shit on another monitor that EXPECTS good video, such as a lot of professional equipment, if it tolerates it at all it will show you the exact mangled video you give it.

That's great, but it's also an opinion... 1) You don't have an end-all TV, and it appears to be a PAL/multi-system TV instead of a native NTSC one 2) we can't reproduce your results at home.

You can't speak for everybody. If that's what people wanted then why are so many emulators implementing NTSC filters these days? Why were hqx, Sai, Super Eagle etc algorithms so popular 10 years ago? Everyone has different tastes.

Speak for your TV. How about taking pictures of your PCE in composite so we can see the difference on your TV at least?

The best place to get technical info on the PCE? Really? lol That's a fan/collector's forum where there are a handful of technical people if that, and it's highly unlikely any of them are also electrical engineers with emphasis in video allowing them to pass judgement on the circuit.

People use that circuit because they don't know better. GameSX published it like 10 years ago, so its been around the block. How can you claim it's the best solution if you admittedly don't know electronics? None of my problems with it are being refuted...

I never once brought up LCD, I'm only talking about CRT. Again you're speaking from personal, possibly limited, experiences. State that you can see the difference on your equipment with your eyes, not a blanket statement for everyone.

*sigh* I already addressed this. It doesn't, you're doing it wrong. Sync starts as a LOGIC signal, it's not meant to drive a transmission line. That doesn't mean it needs amplification, it means you need to not load it so much. The TV's 75 ohm load is incredibly big for a LOGIC output. Also TVs cannot be expected to accept a logic level sync signal.

Again TVs have a DEFINED signal "strength", which I have previously referred to as "level". This is a fact, whether you want to believe so or not.

PC Engine no Subete. Just because it was published in a mook doesn't make it any less of an amateur circuit, sorry to say. If you still want to believe it's the best possible amp, go for it, I've done my part.

Wha? NEC logo? 1) The book is not by NEC (or Hudson) 2) the transistor is an extremely common generic transistor in Japan, it can be replaced by any small signal NPN, 3) the transistor is made by Toshiba.

OT: If you check out the datasheet you'll even see that Toshiba intends it for audio frequency applications (150+ times slower than video), this happens to coincide with the amplifier circuit being talked about which passes for an audio buffer stage.

 

Well I guess it is... so is yours. 1) My TVs (all 5 of them, some crt some lcd) except one, support all systems including NTSC and are also able to display both composite and RGB so I know the difference not only on the PCE but on other consoles as well. RGB is obviously superior on all of them 2) Of course you can't, last time I checked TVs in the states don't support RGB, but ofcourse there are crt monitors... so I guess your experience with RGB is limited.

Emulators are a different thing and people might like experimenting with filters to see how they look like. Playing on the real thing is a different matter though and when someone does, he wants the real thing or as close as he can get to that. I believe I speak for most of the people.

Why don't you? You're the one supporting something that goes against something thats common knowledge and opinion. Convince us. There are a lot of pictures on the internet showing the same frame of a game on both composite and RGB already and guess which one looks better. Knock yourself out http://www.youtube.com/watch?v=qvl2whFM04s
http://www.chrismcovell.com/gotRGB/screenshots.html

For a simple reason... it works and it gives great picture that I (and many many others using it) have confirmed with my own eyes. The schematics were not published by GameSX by the way, just passed on.

At least it was published somewhere and most certainly if it works well or not has been confirmed by hundreds. Which is more than I can say for your claims.

 

Id suggest not arguing with Calpis unless you are going to use technical facts rather than opinion.

You are using knowledge assumed, just because something appears to work. Caplis is using electronics knowledge and facts, you are just using "because it works", which isnt really valid.

Lots of things work, but that doesnt mean they are the correct way of doing things. Which is his point. You have seem to have no reply other than "Well, it works!".

Dont get me wrong, Calpis can come across arrogant and/or confrontational - but he rarely just throws around opinion as fact. His arguments have lots of facts and working electronics theory to back him up. He is worth listening to.

 

1st: I can argue with whomever I want.
2nd: Knowledge on a topic doesn't make someone necessarily right on everything that has to do with that.
3rd: Composite is inferior to RGB by a lot and this is common knowledge for decades. No Calpis's expertese can convince me or anyone else having vision otherwise just by throwing some numbers or blaming the tv set for not displaying composite right.
4th: "Well it works" is what matters. We're playing games here, not designing a satellite thats gonna go into space. Im not saying his theory is necessarily wrong, in practise things are different than in theory some (or most) of the times.
At least I have seen and compared the results this amp provides in real life and have an opinion about it, he hasn't (obviously).

 

1) Sure.
2) Ok.
3) Arguable. Define "A lot" and what is considered "inferior" by most people. There are pros and cons for both sides of the camp.
4) No way. It works to punch a guy in the face and rob him of his money too, but that doesn't mean it's right. Or the correct way to go about getting money. Sure, we're talking about video games (which in life is somewhat trivial) but it doesn't make something any less right or wrong.

 

A lot is this http://www.chrismcovell.com/gotRGB/screenshots.html Distinguishable difference in quality beyond any doubt, thats a lot.
I would like to hear some of these pros of composite and some of the cons of RGB compared to composite. I understand that its somewhat more difficult to have rgb in the US compared to Europe since your tvs don't support rgb but try to be objective on some matters. Overall rgb is much better and thats why a lot of people have their consoles modded for rgb.

 

He isn't so much wrong, as making the situation more complicated than it needs to be. Many of us don't own professional video equipment with the kinds of tolerances he's talking about. Or TVs/consoles whose composite encoding & decoding is good enough to seriously contend against RGB in our own setups. Not that it's impossible. My N64 composite on CRT looks good. (of course it's not yet RGB modded to make any comparison)

 

It's not my opinion that composite is identical to RGB, I've already outlined my points. I've been playing devil's advocate because I have a problem with "by far" and "best" being thrown around.

As close as "he" can get to what? Do people who play on emulators not have a valid opinion? There are more people playing emulators today than there are people playing real consoles. Many aren't experimenting, they will continually play with either HQ scaling, artifact or softening algorithms. As for console players, they don't have the same options available to them so who's to say they wouldn't use HQ scaling if they could? I'm under the impression that for both groups the vast majority of people don't care how the game is viewed as long as it's playable.

All of my PCE are in storage, but I might...

I think these are pretty good examples of composite, especially the video. And that's despite it being such a small monitor (13" or 15"?) having a very poor dot pitch that approaches the pixel width, and the last comparison shots being slightly biased towards RGB because composite is blooming. Look at the System Card licensing text at the bottom of the screen, the font's strokes are 1 pixel wide. You don't think the pixel edges are clearly defined? The only problem I see is somewhat significant chroma interference up close, but 1) separating chroma is the display's job and I don't think the monitor has a 2D much less 3D comb filter, it might not have a comb filter at all, and 2) S-video completely alleviates this problem.

Your eyes can't confirm that your amplifier is drawing more current than the HuCard, or predict that your regulator will melt the PCE's enclosure, until it happens.

Do you similarly use your ears to judge audio amplifier performance?

Posting anything to the internet is publishing it. Maybe somebody submitted it to the site but I don't see any photo/contribution credits and many GameSX articles are derived from similar Japanese material such as Backup Technique so it didn't seem so unreasonable for it to be "original" content. I fail to see how this matters, GameSX has had it up at least 8 years and GameSX practically brought region/controller/RGB-modding to the internet so AFAIK it's the go-to site for such things and where plenty of people would have come across it.

Which claims? AFAIK my claims refer to TV standards which are "confirmed" by the BILLIONS of TV sets produced worldwide since the dawn of color NTSC.

As it's been said over and over again, "by a lot" is completely subjective. I never said composite is BETTER than RGB, that's an illogical statement. In the PCE's case however one might argue it due to the color hinting, and the fact that RGB requires modding the console... With the FC/NES on the other hand I would definitely argue that composite is better for compatibility and aesthetic reasons, and I have many times on this board even.

I'm not going to install said amp to confirm what I already know. I can tell you unquestionably that the THS integrated amp is better in every way and I'm not going to test that "theory" either. (Personally I don't enjoy maiming consoles.)

This is a hunch, but from your statements I'm afraid you're drawing a parallel between video and audio signals. I understand why you would do this, but to do so is incorrect, it's a vast oversimplification of a complex system.

I think the generalizations in this thread aren't depicting the situation complicated enough, so that's why I'm still here. It's important to see multiple sides of a story and some sides few people will tell. By doing so I hope I can convince a few people to take the red pill.

BTW, I'm not really dealing with the theoretical here.

 

There is one fatal flaw we're overlooking. PCE does not adhere to the NTSC standard as written to begin with. Television broadcasts (the original intent for NTSC) were interlaced, not progressive.