I dialed in a G90 yesterday that was being fed 1080p@72Hz from a Lumagen HD (I think). It looked good but was a bit soft. Not a lot, just a little. Is 1080p@ 72Hz more than the G90 can handle?

I dialed in a G90 yesterday that was being fed 1080p@72Hz from a Lumagen HD (I think). It looked good but was a bit soft. Not a lot, just a little. Is 1080p@ 72Hz more than the G90 can handle?

Yes Phil, this is above the rated bandwidth of the PJ. I still have to try it yet myself. I've been running 1080P@60hz.

Cliff

Cliffy, that's what I was thinking. We already made plans for me to come back in a week or two to dial in 1080p@60 to see if we could get it looking a little sharper. We're also going to try connecting Mike's HD sources (HD-DVD and Bluray) directly to the G90. I think that will put us at 1080i@60, which is probably way too low for a G90, but it will eliminate the Lumagen as a possible cause of the softness.

Why didn't Sony put a little more effort in the G90s video section? They should have been able to do 200MHz with their resources. Maybe when it was designed there weren't any sources that needed it? Computer resolutions of 1600 x 1200 have nearly the same bandwidth requirements as 1080p. I can't imagine no-one was using that, though.

Pic of the RGB preamp used in the G90. Spec sheet at:

http://cache.national.com/ds/LM/LM1283.pdf

There is a gamma circuit driving the pre-amp. I can't find any info on it.

The output amps are VPJ15 which are 150MHz?

Scott

Hmm is there any chance of a MP mode to up the bandwidth? Just a pipe dream I'm not a board tech so...

That gamma correction circuit makes no sense at all. My thought is to simply remove it and go with a HFA1100 on blue only, as what's in the Marquee. And as far as gamma corection would be concerned, Ken Witcomb measured the gamma on Mark's 9500LC, and I'm sure it's better than what's already on a stock G90.

With that circuit out, there should be a substantial increase in bandwidth performance.

Now, why they took a short cut and used the LM1283 (140mhz) is beyond me. You would think they would have used either the AD834 (500mhz) or AD835 (250mhz), and built the rest of the circuit from discrete components.

The neck boards looks very capable, especially since they're using duals. But based on the two chips in the preamp, I'm surprised it's able to do 1080P

is this something that you would be able to do in the future Mike? 500 MHZ on a G90 would be insane... Hell 250mhz would be...

Looks like we have a new mod for the 90...... :D

The "MPG90 500Mhz" :) ...

is this something that you would be able to do in the future Mike? 500 MHZ on a G90 would be insane... Hell 250mhz would be...

Well, it's something that i might take a stab at later, but 500Mhz is not going to be possible. A more reasonable goal would be around 165mhz. And that may be somewhat of a problem for me. So Scott may be the best for that goal, because he's the bandwidth expert. he's also more capable of doing circuit redesigns than I am. I'm a performance tweaker that can also do some wonders with bandwidth, but those figures are out of my reach.

Bandwidth is not easy. If you see a 500mhz device in the video chain, it does not mean that the video chain is capable of 500mhz. It only means that there's a device in the chain that's capable of bandwidths UP-TO that rating. So, when dealing with a video chains, you'll want the least amount of devices in that chain, because each one can/will degrade the overall bandwidth to some degree. So it's best to have a short (less components) video chain, that has high bandwidth rated components. That way you'll stand a better chance at preserving a higher level of bandwidth performance through the video chain, because there will be bandwidth losses regardless.

If I recall correctly, you're of the view that given sufficient bandwidth, an 8" LC PJ with aggressive raster should be able to manage 1080p.

There have been differing reports on the ability of a G70 to do 1080p, and I wonder if the softness that some have reported is due to bandwidth constraints?

If b/w is the culprit, I imagine (given the #s of G70s in circulation) that you would find a fair bit of demand for a mod that increased b/w and made the G70 a true 1080p performer.

Any chance of an MP bandwidth mod for the G70?

If I recall correctly, you're of the view that given sufficient bandwidth, an 8" LC PJ with aggressive raster should be able to manage 1080p.

There have been differing reports on the ability of a G70 to do 1080p, and I wonder if the softness that some have reported is due to bandwidth constraints?

If b/w is the culprit, I imagine (given the #s of G70s in circulation) that you would find a fair bit of demand for a mod that increased b/w and made the G70 a true 1080p performer.

Any chance of an MP bandwidth mod for the G70?

After seeing the video chain of a G90, and already knowing that a G70 cannot resolve 1080P, I would say that It's not going to be something that I could make happen. In other words, if i could guess the actual bandwidth capabilty of the G90 based on the components in the video chain, I would guess that it's around 100mhz. I could probably work something out of the G90, but the G70 would need to be in the mighty hands of Scott.

And the only reason that i've been able to make this happen with a marquee, is because a marquee uses the same high bandwidth video chain in both 8" and 9" projectors. So that makes it easy. However, because of the design of the video chain in the marquee, I've been able to greatly increase the bandwidth on a few of them, and that's why I have a 8" 8500 (non LC) kiicking bandwidth.

Mike,

Thx. for the informative reply.

I think this is an issue with broad interest and I've started a new thread on the abilities of the G70 vs. G70VR wrt 1080p. Its been reported that the G70VR does a good job at 1080p and apparently its due (at least in part) to the fact that the G70VR has 'deeper focusing' lenses.

I'm not convinced that that is the entire story, and am curious if the VR has better bandwidth (in addition to better lenses).

At any rate, whether the VR has better bandwidth or not, your experience suggests that bandwidth alone should make a significant difference in an 8"er's ability to satisfactorily resolve 1080p.

Will send a pm out to the 'mighty Scott'.

I have to ask the obvious qoestion here Phil. Why would you want to set up 1080P 72??
For DVD playback 1440 x 960 makes a lot more sense than 1080P, and 72hz is not an issue here. Scanlines are almost impossible to see close up at this resolution never mind at the viewing distance.
For 1080I HD playback which has been recorded at 1080I 59.94HZ 1080P 59.94 makes perfect sense.
So I guess I just don't get it??
Also are you sure that the softness you are getting is coming from the G90 and not the Lumagen? HD deinterlacing on the Lumagen used to be a bit soft, but then you wouldn't be running 72Hz refresh for that either??

Terry

After seeing the video chain of a G90, and already knowing that a G70 cannot resolve 1080P, I would say that It's not going to be something that I could make happen. In other words, if i could guess the actual bandwidth capabilty of the G90 based on the components in the video chain, I would guess that it's around 100mhz. I could probably work something out of the G90, but the G70 would need to be in the mighty hands of Scott.

And the only reason that i've been able to make this happen with a marquee, is because a marquee uses the same high bandwidth video chain in both 8" and 9" projectors. So that makes it easy. However, because of the design of the video chain in the marquee, I've been able to greatly increase the bandwidth on a few of them, and that's why I have a 8" 8500 (non LC) kiicking bandwidth.


Scott,

What say you? Can it be done (without breaking the bank that is)? If so (given the popularity of the G70) I'm sure you'll find a host of members clamoring for a mod that would sharpen the 1080p resolving ability of their otherwise highly capable G70s.

I have to ask the obvious qoestion here Phil. Why would you want to set up 1080P 72??
For DVD playback 1440 x 960 makes a lot more sense than 1080P, and 72hz is not an issue here. Scanlines are almost impossible to see close up at this resolution never mind at the viewing distance.
For 1080I HD playback which has been recorded at 1080I 59.94HZ 1080P 59.94 makes perfect sense.
So I guess I just don't get it??
Also are you sure that the softness you are getting is coming from the G90 and not the Lumagen? HD deinterlacing on the Lumagen used to be a bit soft, but then you wouldn't be running 72Hz refresh for that either??

TerryTerry,

I didn't. A TAW DVD player, an HD-DVD player and a Bluray player are all running thru the Lumagen. The Lumagen was already setup at 1080p@72. It didn't dawn on me to ask Mike what refresh rate he was running until after I had already finished the setup, and we were staring at the picture trying to figure out why it wasn't as sharp as either of us had expected.

As I mentioned in my second post, before I left, we made plans for me to come back and do a setup without the Lumagen in the signal path, as well as do a 1080p@60 setup with the Lumagen. That will allow us to tell if the Lumagen is the culprit. From what you say, it sounds like it probably is.

The internal test grids looked really sharp and were tightly converged, much better than I can get my G70. My G70 is really sharp, so I was expecting to be blown away after we got it setup. It looked good, but not like I think it should.

The internal test grids looked really sharp and were tightly converged, much better than I can get my G70. My G70 is really sharp, so I was expecting to be blown away after we got it setup. It looked good, but not like I think it should.

If the internal patterns were as you described (sharp), then I would suspect the Lumagen or anything in the signal path between the Lumagen and the G90.

Not sure which one, but there's an earlier version Lumagen, that had a problem with higher rates.

One of you guys needs to come up with a G90 video section mod. Most G90 owners have already spent a small fortune on their PJs and setups. I imagine almost all of them, if not all of them, would be a buyer for the mod.

If the internal patterns were as you described (sharp), then I would suspect the Lumagen or anything in the signal path between the Lumagen and the G90..Mike,

As I think back on it, the Lumagen grid (which we used to do the setup) did not look as sharp. All of this didn't dawn on me at the time, but thinking about it today, it really looks like the Lumagen is the problem. I guess chalk this up to my zero experience with scalers.

What about running Marquee neck cards in a G90? I've heard of other neck card transplants being done successfully from one PJ to another, why not the G90?

Of course, that'd only handle the final drive amplification, not the video input/front end.

I've never even SEEN the input board on a G90 so I can't even guess as to how moddable it might be.


Who am I kidding? The closest I've actually come to a G90 is pictures.


I hope to rectify that situation someday.

CJ

"For 1080I HD playback which has been recorded at 1080I 59.94HZ 1080P 59.94 makes perfect sense."

Terry, a decent HD capable processor should be able to perform IVTC and extract the 23.976fps progressive frames out of the 60i for films. Then you need to play back at a multiple of 23.976. That's why. I run my XG at 1080i 71.928hz for this reason.

1080i 59.94 only applies to very very few TV shows shot interlaced (Sports maybe? Stuff like Lost is progressive).


-------------------------------------------------

And comments from various people that a G90 won't "resolve" 1080p 60hz just seems totally ludicrous to me, having seen a G90 at various 1080p refresh rates - it is really SHARP. Especially when there were all sorts of comments about how an XG was "resolving" it the other day (nice work with the XG, but it's not in the same class based on my observations).

If ever get a G90 I damn well will be giving 1080p 72hz a go.

One of you guys needs to come up with a G90 video section mod. Most G90 owners have already spent a small fortune on their PJs and setups. I imagine almost all of them, if not all of them, would be a buyer for the mod.


No argument there, but to the extent a solution is implementable in the G70 as well, you could find a far greater market to amortize development costs over.

And even if the G70 needs a completely different bandwidth mod, I would imagine it would actually be far more profitable to come up with a G70 mod than a G90 mod. After all, it appears 90% of G90 owners are pretty happy with the 1080p performance they currently have while, the opposite is true w/ G70 owners (90% unsatisfied w/ 1080p performance).

If the number of G70 forum members is as little 4x G90 members (and I think I'm being conservative), you're looking at a G70 addressable market that is more than 35X the G90 market.

Granted we're of rather more modest means, but heck, the sheer size of the market should make a more affordable product (smaller margins, but larger volumes) reasonably profitable for someone like Scott.

Come on Scott, What do you say? Can it be done?

That gamma correction circuit makes no sense at all. My thought is to simply remove it and go with a HFA1100 on blue only, as what's in the Marquee. And as far as gamma corection would be concerned, Ken Witcomb measured the gamma on Mark's 9500LC, and I'm sure it's better than what's already on a stock G90.

With that circuit out, there should be a substantial increase in bandwidth performance.

Now, why they took a short cut and used the LM1283 (140mhz) is beyond me. You would think they would have used either the AD834 (500mhz) or AD835 (250mhz), and built the rest of the circuit from discrete components.

The neck boards looks very capable, especially since they're using duals. But based on the two chips in the preamp, I'm surprised it's able to do 1080P


"Now, why they took a short cut and used the LM1283 (140mhz) is beyond me. You would think they would have used either the AD834 (500mhz) or AD835 (250mhz), and built the rest of the circuit from discrete components." MP quote.

Why indeed? I can't imagine why. If your neck card can do 150MHz why would you feed it a 140MHz signal? The National chip is very convenient as it does everything that you would want. OSD, drive control, contrast, etc. To get the best from the 150MHz neck cards they should have sent it a minimum 200MHz signal. The parts were available.

Scott

Yeah it's to bad they didn't go that route, maybe it can be modded in the future.

"Now, why they took a short cut and used the LM1283 (140mhz) is beyond me. You would think they would have used either the AD834 (500mhz) or AD835 (250mhz), and built the rest of the circuit from discrete components." MP quote.

Why indeed? I can't imagine why. If your neck card can do 150MHz why would you feed it a 140MHz signal? The National chip is very convenient as it does everything that you would want. OSD, drive control, contrast, etc. To get the best from the 150MHz neck cards they should have sent it a minimum 200MHz signal. The parts were available.

Scott

Hey Scott,

Maybe you should take a nice trip to the windy city and make my G90 a little test bed for these parts. :)

That reminds me.....

I need to call Brenda.....

Cliffy

Make sure you have a new firmware for the Lumagen in question. The modern Lumagen builds are not soft and you should see a razor sharp image with the Lumagen @ 1080p 60hz. Early on the Lumagens did tend to be soft but they have made leaps and bounds. I think that the softness you saw was likely due to frequency attenuation with 1080p @ 72 Hz.

I run my G90 at 1080p 60 for video from a Lumagen HDQ. I will be doing some work to see if I can get 1080p 72 for HD DVD once I get the G90 in its final home. I honestly don’t expect 1080p @72 Hz to be realistic though.

In any event, I have hooked my Sencore VP403 to the Lumagen through DVI-D at 1080i. The Lumagen deinterlaces 1080i and the G90 perfectly resolves the 1080p on a frequency burst. The response looks the same as compared to my VP403 hooked directly to the G90 by RGBHV at 1080p 60 Hz from the Sencore.

I’ve also looked at the analog outputs from the Lumagen with RGBHV on my oscilloscope. There is just a hair of attenuation from a frequency burst on the Lumagen running 1080p 60 Hz at the output.

craigr

Make sure you have a new firmware for the Lumagen in question. The modern Lumagen builds are not soft and you should see a razor sharp image with the Lumagen @ 1080p 60hz. Early on the Lumagens did tend to be soft but they have made leaps and bounds. I think that the softness you saw was likely due to frequency attenuation with 1080p @ 72 Hz.

I run my G90 at 1080p 60 for video from a Lumagen HDQ. I will be doing some work to see if I can get 1080p 72 for HD DVD once I get the G90 in its final home. I honestly don’t expect 1080p @72 Hz to be realistic though.

In any event, I have hooked my Sencore VP403 to the Lumagen through DVI-D at 1080i. The Lumagen deinterlaces 1080i and the G90 perfectly resolves the 1080p on a frequency burst. The response looks the same as compared to my VP403 hooked directly to the G90 by RGBHV at 1080p 60 Hz from the Sencore.

I’ve also looked at the analog outputs from the Lumagen with RGBHV on my oscilloscope. There is just a hair of attenuation from a frequency burst on the Lumagen running 1080p 60 Hz at the output.

craigr

that should put the Lumagen "problem" to rest ;)

thanks Craig

-Gary

Hey,

I've got to wonder why someone wouldn't just buy a Marquee in the first place. The Marquee has great circuitry and reliability and it's generally cheaper and it weighs less and is smaller and if MP mods are what you want all you need to do is ring up Tim.

I would jump at the chance to own a G90 esp at a price I could afford (currently next to nothing) but if I ever upgrade away from my current G70 it's the Marquee's that are on my list.

-B

You got it Brian, I have my sights set on a MP 9500LC or a Greg Eisemann 1209s with 180mhz bandwidth ;)

-Gary

To get back on the subject (if you guys don't mind ;) ), I e-mailed Mike about the Lumagen firmware upgrade. I'll let you know what he reports.

I have to ask the obvious qoestion here Phil. Why would you want to set up 1080P 72??

I'm with Mark. You want this for all broadcast HD movies you watch (HBO HD, Starz HD, etc) as well as HD-DVD and BD playback.

Dave

I'm with Mark. You want this for all broadcast HD movies you watch (HBO HD, Starz HD, etc) as well as HD-DVD and BD playback.

Dave

I don't, I cannot stand film played back at 72hz or 48hz, I like my plain old 30/60hz

72hz/48hz is headache/eye strain city for me, I have tried it so many times from so many different pieces of gear, be it scalers, HTPC's, Momitsu, it never did it for me

I just hate it

-Gary

I'm with Mark. You want this for all broadcast HD movies you watch (HBO HD, Starz HD, etc) as well as HD-DVD and BD playback.

DaveYou're quoting Terry, not Mark. Mark would like to try 72Hz if he had a G90 or comparable PJ.

The reason you don't understand why my friend is because you didn't read the whole thread: http://www.avsforum.com/avs-vb/showthread.php?p=7971313&&#post7971313

If you're not going to bother to read the whole thread (I also do that all the time), you might think twice about posting in it. ;)

You're quoting Terry, not Mark.

I quoted Terry. I was agreeing with Mark who had already answered Terry's question.

The reason you don't understand why my friend is because you didn't read the whole thread: http://www.avsforum.com/avs-vb/show...3&&#post7971313

If you're not going to bother to read the whole thread (I also do that all the time), you might think twice about posting in it.

I don't follow here. I did read the whole thread. Terry's question seemed to be a Philosophical "why do you need 1080p@72"? Mark answered why and I agreed.

Dave

72hz/48hz is headache/eye strain city for me

I'd be curious to see a physiological analysis of this.

Having frames displayed at 60Hz as AAABBCCCDD is OK, but at 72Hz AAABBBCCCDDD messes with you? That is weired because it is the same exact image just being redrawn a bit faster, before much phosphor fade. I'm not sure how/why 72 would bother you--but I'm pretty sure this is quite unusual.

Dave

Dave, what did you drink for lunch? ;)

And comments from various people that a G90 won't "resolve" 1080p 60hz just seems totally ludicrous to me, having seen a G90 at various 1080p refresh rates - it is really SHARP. Especially when there were all sorts of comments about how an XG was "resolving" it the other day (nice work with the XG, but it's not in the same class based on my observations).

If ever get a G90 I damn well will be giving 1080p 72hz a go.To repeat what Mark says, "I damn well will be giving 1080p 72hz a go"

Terry,

I didn't. A TAW DVD player, an HD-DVD player and a Bluray player are all running thru the Lumagen. The Lumagen was already setup at 1080p@72. It didn't dawn on me to ask Mike what refresh rate he was running until after I had already finished the setup, and we were staring at the picture trying to figure out why it wasn't as sharp as either of us had expected.To paraphrase my own words: I didn't know the Lumagen was set at 72Hz until I had already finished setting up the PJ. It took me quite a while to do that setup. I wasn't about to do another one on that particular day. We made plans before I left for me to come back and do a 60Hz setup, as well as a setup without the Lumagen in the signal path.

Phil, we are talking about different parts of this discussion. I'm not talking about your case, or if 1080p@72 is doable or anything like that. I'm talking about this quote from Terry:

I have to ask the obvious qoestion here Phil. Why would you want to set up 1080P 72??
For DVD playback 1440 x 960 makes a lot more sense than 1080P, and 72hz is not an issue here. Scanlines are almost impossible to see close up at this resolution never mind at the viewing distance.
For 1080I HD playback which has been recorded at 1080I 59.94HZ 1080P 59.94 makes perfect sense.
So I guess I just don't get it??

In this quote, he seems to suggest that there are valid reasons for the following resolutions:
1440x960@72 (he doesn't specify refresh, but I assume he would want 72 for movies).
1080p@60

He seems to see no reason for EVER doing 1080p@72. I believe those reasons are:
1) HD movies that are broadcast as 1080i@60 (you want to get these to 1080p@72, not 1080p@60).
2) 1080i from an HD disc player (for the same reason above).

Dave

I'd be curious to see a physiological analysis of this.

Having frames displayed at 60Hz as AAABBCCCDD is OK, but at 72Hz AAABBBCCCDDD messes with you? That is weired because it is the same exact image just being redrawn a bit faster, before much phosphor fade. I'm not sure how/why 72 would bother you--but I'm pretty sure this is quite unusual.

Dave

Dave I do not want to put words in someones mouth, but me and Mike Parker were discussing this same issue in a old NeuNeo thread of mine(in the CRT forum) and I am fairly certain has was of my point of view also, not liking 72hz

Mike please comment on this :)

the way the motion looks makes me just ill, it looks so wrong to me, I know there are others who agree with this, just not very many ;)

-Gary

And comments from various people that a G90 won't "resolve" 1080p 60hz just seems totally ludicrous to me, having seen a G90 at various 1080p refresh rates - it is really SHARP

No, this is not the opinion of some folk, this is what's indicated from the manufacturers specs on one of the IC's being used in the video chain of the G90:

http://www.national.com/search/search.cgi/main?keywords=lm1283
The LM1283 is a full feature video amplifier with OSD inputs, all within a 28-pin package. This part is intended for use in monitors with resolutions up to 1280 x 1024. The video section of the LM1283 features three matched video amplifiers with blanking

Based on what's (upto 1280 x 1024) claimed from the manufacturers specs on this device, a maximum resolution of 1280 x 1024 is not going to get you 1080P/60

Now if the manufacturer made a mistake in their specs, and that IC will actually go "up to" 1600 x 1200, then 1080p/60 is very possible.

the way the motion looks makes me just ill, it looks so wrong to me, I know there are others who agree with this, just not very many ;)



Wierdos. :D

Dave I do not want to put words in someones mouth, but me and Mike Parker were discussing this same issue in a old NeuNeo thread of mine(in the CRT forum) and I am fairly certain has was of my point of view also, not liking 72hz

Mike please comment on this :)

the way the motion looks makes me just ill, it looks so wrong to me, I know there are others who agree with this, just not very many ;)

-Gary

1080P@60hz on the G90 rocks. I don't see any need to go higher as well.

Cliff

Phil, we are talking about different parts of this discussion. I'm not talking about your case, or if 1080p@72 is doable or anything like that. I'm talking about this quote from Terry:



In this quote, he seems to suggest that there are valid reasons for the following resolutions:
1440x960@72 (he doesn't specify refresh, but I assume he would want 72 for movies).
1080p@60

He seems to see no reason for EVER doing 1080p@72. I believe those reasons are:
1) HD movies that are broadcast as 1080i@60 (you want to get these to 1080p@72, not 1080p@60).
2) 1080i from an HD disc player (for the same reason above).

Dave
Dave,

Two HD players as well as a SD player were connected to the Lumagen. The Lumagen was the only thing connected to the G90. The Lumagen was outputting 1080p. So, everything was running 1080p because everything was running thru the Lumagen. Frankly, that was good news to me, because it meant I only had to dial in 1080p. I didn't want to have dial in another resolution. The DVD player is connected via SDI to the Lumagen. The HD players...either RGB or HD component, I'm not sure. If the Lumagen can be set to output 1080p for the HD players and 960p for the DVD player, I'll do that. Someone will have to explain how get the Lumagen to do that though, as I have zero experience with it.

But really, SD DVD looked great at 1080p. It may not be mathematically idea, but it didn't seem to matter. SD DVD was not the problem, it was HD DVD. I'm going to concentrate on getting HD DVD to look good at 1080p. Once that's accomplished, if SD DVD doesn't look good, I'll set up a 960p memory block. If it does look good at 1080p, as much as it may bother you guys, I'm not going to fix what ain't broken. ;)

My setup is basically the same. Everything runs through my Lumagen and comes out at 1080p. Except for the HD cable box, which runs 1080i via DVI to the Moome input card in the Marquee.

It's a pretty efficient way to run. I've always found that when the Marquee switches from one mode to another, minor convergence errors always seem to creep in. Oh, sure, I can iron them out in just a matter of seconds, but it's better to stick with one output resolution and never have to touch a thing.

Just for experimental purposes, I'm going to rework the system so everything, including the Lumagen, runs through the Marquee switcher and from there goes to the Marquee via its analog outputs. It should give me a little more system flexibility as I have a full
complement of input cards for the switcher and just finally got the control cable for it.

CJ

Phil,
If you are pleased with the setup and did a reset back to factory before you did this setup (which is a good idea but not critical), all you need to do is hold down the memory key and it will come up and ask if you want to save the focus and registrations as defaults. Do that and when you switch to 1080P 60 the setup will be pretty close just requiring a slight touchup for focus and registration.

Mark I agree with what you are saying about 23.xx FPS but like the way the 1080P 60 setup looks and works on the G90. What would the improvement be going to 72Hz?? Slow scan stutter?? I don't get any on HD material for film or video. Picture saturation?? No problem there at 1080P. Besides I'm to lazy to change refresh between film and video.....lol

Terry

But really, SD DVD looked great at 1080p. It may not be mathematically idea, but it didn't seem to matter. SD DVD was not the problem, it was HD DVD. I'm going to concentrate on getting HD DVD to look good at 1080p. Once that's accomplished, if SD DVD doesn't look good, I'll set up a 960p memory block. If it does look good at 1080p, as much as it may bother you guys, I'm not going to fix what ain't broken. ;)

Yeah, if it looks good - don't worry about it, though i think you're on a good path to getting the best out of your setup.

Since SD DVD looks OK, maybe it has something to do with SDI. Therefore the problem with HD DVD may have more to do with the way you're connecting it to the Lumagen. I don't recall you saying how that was being done.

Sometimes it takes a little playing around to get things right, and it seems that you may have to focus more at the Lumagen's inputs (cables, type of input, etc) than anything with the G90. I know you're from the world that believes that the quality of cables has very little to do with the absolute best in image quality, but trust me, they can play a big deal in getting the best image. So you may need to look into the cables as well, especially for HD. And I'm saying that the cables would be critical even at distance of 3'

It would be nice if someone would take on a G90 to offer tech support for those of you who have them. I would, but I've just decided to take on the 1292. As much as I hate to deal with being one of the "limited" sources for technical help on the 1292, I think it's only fair for me to do so.

I don't, I cannot stand film played back at 72hz or 48hz, I like my plain old 30/60hz

72hz/48hz is headache/eye strain city for me, I have tried it so many times from so many different pieces of gear, be it scalers, HTPC's, Momitsu, it never did it for me

I just hate it

-Gary

That's so incredibly backwards...are you wearing your reality inversion sunglasses?

I will admit that 48hz can flicker, but can't you see THE JUDDER at 60hz???

I really, really don't get that.

"What would the improvement be going to 72Hz?? Slow scan stutter??"

Terry, well, yes. Everything that moves judders. Sometimes it's not that obvious, it depends one the speed of movement/panning, but other times it's hideous.

I do realise that 1080p 72hz is going to be softer. The G90 I did a PC for look great at 48hz. For some reason the flicker (which usually drives me nuts) didn't bother me.

I spent some time watching The Two Towers 1080i TS file on the G90 at 48hz. It was just breathtaking.

No, this is not the opinion of some folk, this is what's indicated from the manufacturers specs on one of the IC's being used in the video chain of the G90:

http://www.national.com/search/search.cgi/main?keywords=lm1283


Based on what's (upto 1280 x 1024) claimed from the manufacturers specs on this device, a maximum resolution of 1280 x 1024 is not going to get you 1080P/60

Now if the manufacturer made a mistake in their specs, and that IC will actually go "up to" 1600 x 1200, then 1080p/60 is very possible.

I hear you Mike. Maybe the G90 is hobbled by this part, maybe it's not - got one handy and a 400mhz scope :)

I'm just reporting what I saw - I was very impressed with the sharpness. From WM's pics of the HD2K (I think that was it), which showed the digital as sharper, the G90 still has room for improvement.

But I would be very, very happy with a G90 (and a parts chassis..).

Mark

EDIT: Hey wait, where did Mike's post go?

That's not 3:2 motion judder, that's interlacing field line twitter, and they are not related.


3:2 Judder is caused by the crazy cadence required to get 24fps film played back at 60hz.

Look for "juddery" motion on pans. It is a motion issue - a temporal problem.

When a film pans slowly, the scene should move smoothly, not as a series of tiny little jerks.

Mark I most certainly do see the jittery motion on pans with 60hz, no doubt about that, but that is much more acceptable to me than the 71.928hz viewing
it just looks so weird to me, something about the movement I do not like, it doesn't look natural and has a fill too it like the speed has been changed or something, sorta reminds me of how Pal looks converted to NTSC, movement just doesn't look right at all to me

-Gary

If the Lumagen can be set to output 1080p for the HD players and 960p for the DVD player, I'll do that. Someone will have to explain how get the Lumagen to do that though, as I have zero experience with it.
The Lumagen has an "independent output mode" that must be enabled and configured. There are a number of ways that the "independent output mode" can function; it can be set to change the output scan rate per input, but also with respect to a given scan rate on a given input. In can be made to function automatically or manually.

An easy "independent output" configuration would be to firstly set up the Lumagen's output to be 1080p @ 60 Hz for all inputs and all scan rates going into the Lumagen. You could then enable "independent output mode" and set it to “Auto-Independent.” Then configure the SDI input so that when selected, the Lumagen switches to output 960p @ 72 Hz. Here are the word for word instructions.


To enable independent output mode, select OUT->MODE, and change it to either independent (INDEP), or automatic-independent (AUTO-INDEP). There are a total of 8 output configurations. Note that when the output mode is changed from .Same. to "Independent", the current output configuration is copied to all 8 independent output configurations and that all memories select output configuration 0. If the Lumagen is switched back from "Independent" to "Same" output mode, Output configuration 0 will be used as the single output configuration, and all other outputs configurations will be lost.

For Input 5 to 10 (labeled 0) select the desired output configuration (IN -> OUTSEL). Inputs 1 to 4, support an output configuration for each of four possible input resolutions (PC, 480i/480p (or 576i/576p), 720p, 1080i). As you enter IN->OUTSEL, you will see that you can associate an output number for every input resolution. The PC memory is used for any single input resolution other than those listed above. For these HD inputs, when Multiple-Output-Mode is enabled, the output-configuration numbers for each of these is listed as four numbers separated by a ./. in the order shown above (i.e., PC, SD/ED, 720p, 1080i). The output-configuration number for each of these sub-memories must be set independently.

To create a new output configuration, select an input and input memory to be changed. Then select a new output configuration number (IN -> OUTSEL). As an example consider a system with two sources, a DVD player and a satellite receiver. It is desired that the output resolution be 960p when the DVD is the source, 960p output when the satellite receiver is receiving SD material (e.g. 480i) and 1080i when the satellite receiver is receiving 1080i HD material. This can be achieved as follows (assumes the box is at factory default state):

Select 960p output resolution and configure.
Save the configuration (optional)
Select multiple output mode
Select the satellite input
View a 1080i source channel
Change the 1080i submemory output configuration number to 1
With 1080i source coming from the satellite, select 1080i output and configure
Save the configuration

After this, when the DVD player is selected the output will be 960p, when the satellite is selected and it is outputting 480i, 480p, 576i or 576p, the output will be 960p, and when the satellite is selected and it is outputting 1080i, the output will be 1080i.
Phil, when you go back to redo the projector do as Terry says here.


If you are pleased with the setup and did a reset back to factory before you did this setup (which is a good idea but not critical), all you need to do is hold down the memory key and it will come up and ask if you want to save the focus and registrations as defaults. Do that and when you switch to 1080P 60 the setup will be pretty close just requiring a slight touchup for focus and registration.
That way you can then set the Lumagen to 1080p 60 Hz and 98% or what you already did will be retained and your setup will be quick. After you've redone the projector at 1080p 60 Hz you can then set the Lumagen to 960p by way of the independent output mode.

The G90 will re-sync to the new scan rate and you can set up a new memory for 960p 72 Hz on the G90. The G90 will allow you to touch up minor convergence and magnetic focus error for the 960 input memory. The G90 will retain memories for each input scan rate that are independent from one another. The G90 will then automatically switch between the input memory for 1080p 60 Hz and 960p 72 Hz when the signals are applied.

The Lumagen will also auto switch the output mode with respect to the input source and resolution. The result is simple interaction with the end user and an enormously powerful application with multiple input and output scan rates. Have I mentioned that the Lumagen’s rock…

All that being said I have to agree with the following.


Mark I agree with what you are saying about 23.xx FPS but like the way the 1080P 60 setup looks and works on the G90. What would the improvement be going to 72Hz?? Slow scan stutter?? I don't get any on HD material for film or video. Picture saturation?? No problem there at 1080P. Besides I'm to lazy to change refresh between film and video.....lol
And also add that... I know the G90 can do 1080p @ 60 Hz and perfectly resolve all the way out to 1920. The Lumagen is very good at scaling 480i to 1080p from the DVD on SDI. The Luamgen is also very good as converting the 24 Hz DVD to 60 Hz for 1080p. Because of this, you may notice little to no difference between running the DVD at 1080p 60 Hz or 960p 72 Hz.

Oh yeah, the Lumagen much prefers digital inputs. If the G90 has an HDCP DVI board I'd suggest running the HD DVD through DVI. If you don't have an HDCP IB then I guess you are stuck with component video from the HD DVD.

craigr

"The Luamgen is also very good as converting the 24 Hz DVD to 60 Hz for 1080p"

Does this imply that it is interpolating frames?

Would it be able to do so for HD material as well? (Not likely, barely anything will do IVTC properly so far..)

"The Luamgen is also very good as converting the 24 Hz DVD to 60 Hz for 1080p"

Does this imply that it is interpolating frames?

Would it be able to do so for HD material as well? (Not likely, barely anything will do IVTC properly so far..)

You da man Mark ;)

EDIT: Hey wait, where did Mike's post go?

That's not 3:2 motion judder, that's interlacing field line twitter, and they are not related.


3:2 Judder is caused by the crazy cadence required to get 24fps film played back at 60hz.

Look for "juddery" motion on pans. It is a motion issue - a temporal problem.

When a film pans slowly, the scene should move smoothly, not as a series of tiny little jerks.

I deleted it because I wanted to take another look at it to make sure. I'm in full agreement that the vertical rate should be in exact multiples to avoid judder, but again, I've been watching 1080P/60 for several days now, with no noticable judder. And maybe i've not been really looking for it, or may not have been using a known source material that shows it off. And that's why i wanted to revisit that before i left the post out there.

I'll look at it again, but the big problem that I've been having with 1080I/60 is the bouncing horizontal lines. I'm not getting the bouncing lines with 1080P/60. Not sure if I've been paying much attention to this in regards to judder.

Why am I getting bouncing lines at 1080I/60, but not at 1080P/60?

And is the bouncing lines the same as the judder that you speak of?

However, I do understand the importance technically of having things done at the correct math of 24, 48 and 72

I know the G90 can do 1080p @ 60 Hz and perfectly resolve all the way out to 1920.
craigr


Can you do a screen shot of this?

And if so, could you do it showing the actual smpte pattern that has the 6 horizontal and vertical lines in the center?

And if so, could you show this with the upper two lines patterns showing, that will also show (include) that small square pattern right above it?

That small square pattern will confirm resolve, because it's a diagonal over lapping line pattern, that has mini dots in between the cris cross lines. If the projector is properly resolving 1080P/60, that pattern should be CLEAR.

If the projector has a problem resolving 1080P/60, that pattern will blur and look out of focus.

When a projector is capable of "perfectly" resolving 1920 x 1080P/60. The six line patterns would all have equal black and white balance, but the test that really proves "perfect" resolve is that small square.

"The Luamgen is also very good as converting the 24 Hz DVD to 60 Hz for 1080p"

Does this imply that it is interpolating frames?

Would it be able to do so for HD material as well? (Not likely, barely anything will do IVTC properly so far..)
Actually, inverse-telecine deinterlacing is one of the strong points on the Lumagen. Greg Rogers did a review of the current line a month or two ago. It's all explained here. (http://www.lumagen.com/docs/hdq_review.pdf)

craigr

Why am I getting bouncing lines at 1080I/60, but not at 1080P/60?
Probably because you are seeing interlace artifacts with the interlaced signal. A G90 won't look good with 1080i @ 60Hz. You want to deinterlace 1080i 60 Hz sources to 1080p 60 Hz so you have good saturation and no flicker and so that scan lines are invisible.


And is the bouncing lines the same as the judder that you speak of?

However, I do understand the importance technically of having things done at the correct math of 24, 48 and 72
Judder is what you get when you convert 24 Hz to an uneven multiple. Example is converting 24 Hz to 60 Hz. Judder is not related to interlaced flicker.

craigr

1080P@60hz on the G90 rocks. I don't see any need to go higher as well.

Cliff

What do you do about judder, just live with it? Seems like if you are going for best performance, you would want to eliminate this terrible artifact.

Dave

Can you do a screen shot of this?
Yes, but it will be a little while. I'm in Europe until late September and the G90 is in the USA. I can snap a photo when I get back. I almost took a picture before I left but never got around to it.

I can't use the pattern you asked for simply because I don't have easy accessed to it with my calibration suit of equipment (I don’t even have the pattern). I own a Sencore VP403 and it will output a multiburst that includes a one pixel width section in the burst. There is also a sharpness pattern with a burst and other tests. You can see the VP403 patterns here (http://www.sencore.com/vp400/vp400patterns.htm).

Anyway, the G90 will perfectly reproduce the burst all the way out at 1080p 60 Hz. Since the G90 can do a black/white, single pixel width, pattern it's got the bandwidth for the frequency.

Actually, I do have a photo with the burst in it, but I took it too far back from the screen and the camera couldn’t resolve the high requency…

craigr

I haven't heard from Mike to see if he tried updating the firmware of the Lumagen. I'm kind of stuck in limbo until I hear from him.

Terry, I didn't start from scratch on the setup because I had no experience with a G90 and wasn't sure what I was getting into. The key and pin adjustments really threw me off at first, but after some trial and error, and some referring to the manual, I finally got it. Very different from my G70, and very cool! The fine and coarse adjustments also threw me off a little, but only because I kept forgetting to check which mode it was in before tweaking. The coarse mode is indeed coarse. :D It moves whatever you're adjusting a LOT. Other than those differences, it's very much like my G70, and eventually felt right at home. When I go back, I plan on doing the setup from scratch. Mike already has the color balance settings written down. Once I reset it to factory, I'll enter those numbers back in and get to work.

Craig,

You answered many questions I had about the Lumagen. Thanks! One more thing: The lumagen has a function that allows you to move and size the picture. Mike wanted to use the adjustments. I did not! I made these adjustments with the PJ. I'm almost certain Mike had used the Lumagen to make adjustments in the past. I would like to get them set back to default settings so they're not a factor.

Lots of good advice from many people. Thanks a lot! You guys are tha bomb! :D

Yes Phil, the amount and range of adjustments available on the G90 are nothing short of spectacular. What incredible flexibility.
Do the factory reset, and then set up your highest freq setup. Then mem focus and registration data to all memories and you will be amazed at how close to setup you will be at new resolutions. Sony did this better on the G90 than any other CRT I have ever seen.
The lumagen firmware definately needs to be upgraded to the latest. They definately created at soft looking picture with 1080i HD inputs outputting 1080p about 6 months ago but have shown dramatic improvements since then.

Terry

Actually, inverse-telecine deinterlacing is one of the strong points on the Lumagen. Greg Rogers did a review of the current line a month or two ago. It's all explained here. (http://www.lumagen.com/docs/hdq_review.pdf)

craigr


Guys!!!


The article Craigr linked to explains EXACTLY what I have been crapping on about :)

Page 4 "Film mode deinterlacing", and "48/72 hz Output" are what I have been trying to say.

No, there is no Interpolation, and YES you should use 48/72hz.

Thanks for the link Craig ;)

Mark

You answered many questions I had about the Lumagen. Thanks! One more thing: The lumagen has a function that allows you to move and size the picture. Mike wanted to use the adjustments. I did not! I made these adjustments with the PJ. I'm almost certain Mike had used the Lumagen to make adjustments in the past. I would like to get them set back to default settings so they're not a factor.
No problem Phil,

To answer your question… The Luamgen has sizing and position type functions on both the input and the output. Depending on your methodology in calibrating, you might want to leave the size and position controls in the output menu at their defaults.

However, on the Lumagens you must size the inputs. In the input menu there is a size control. In order to have all sources positioned properly you must set the input size for each input at each scan rate. When you adjust the input size, the Lumagen OSD is pretty much self explanatory. You will see either a black boarder around the image or you will see that the image runs over the boarders. Size the image such that it fits perfectly. Below are the instructions to size the input so adjust accordingly.


Adjust the input size and position. This selects which pixels are captured for processing. If the corner being adjusted cannot be seen on-screen, use the output size command described below to reduce the output size, then come back to this step. Adjust the top-left of the image first. Then adjust the bottom-right.

Input top-left: MENU > IN > CONFIG > ADJ > SIZE > TOPL > OK

Input bottom-right: MENU > IN > CONFIG > ADJ > SIZE > BTMR > OK
It sounds like Terry and I have a similar philosophy here.


Do the factory reset, and then set up your highest freq setup. Then mem focus and registration data to all memories and you will be amazed at how close to setup you will be at new resolutions. Sony did this better on the G90 than any other CRT I have ever seen.
After the reset, what I would do is send 1080p @ 60 Hz directly to the projector with my VP403 Sencore. I'd do 1080p @ 60 Hz first since it's the highest frequency signal that will be used (by me).

After that, go back and redo everything for 960p @ 72 Hz…


Terry, I didn't start from scratch on the setup because I had no experience with a G90 and wasn't sure what I was getting into. The key and pin adjustments really threw me off at first, but after some trial and error, and some referring to the manual, I finally got it. Very different from my G70, and very cool! The fine and coarse adjustments also threw me off a little, but only because I kept forgetting to check which mode it was in before tweaking. The coarse mode is indeed coarse. It moves whatever you're adjusting a LOT. Other than those differences, it's very much like my G70, and eventually felt right at home. When I go back, I plan on doing the setup from scratch.
To G90's are just fun to work with. It's like, if something needs to be fixed there is an adjustment to do it.

If you get lost in a full setup just refer to the install manual. It really holds your hand and walks you through most of the process. The IM doesn't go into phosphor usage and maximizing the raster so don't forget that part :cool:

craigr

Guys!!!


The article Craigr linked to explains EXACTLY what I have been crapping on about :)

Page 4 "Film mode deinterlacing", and "48/72 hz Output" are what I have been trying to say.

No, there is no Interpolation, and YES you should use 48/72hz.

Thanks for the link Craig ;)

Mark
No problem.

It's a great review mostly because it was written by Greg Rogers. He's one of those folks who is so knowledgeable about video signals that whenever he speaks I just shut up and listen :) The review isn't just a review, it's an explanation of IVTC; how it works, what it is, etc.

For those who don't know, Greg is the engineer who designed the Accupel HDG-3000...

craigr

The lumagen firmware definately needs to be upgraded to the latest. They definately created at soft looking picture with 1080i HD inputs outputting 1080p about 6 months ago but have shown dramatic improvements since then.
Not to beat a dead horse but...

It’s all been in the last six months that Luamgen has perfected IVTC and the ability to truly resolve 1080p. Originally the Lumagens could not do proper IVTC and also deinterlaced 1080i was rather soft.

I appreciate how Jim and Pat have kept up support and have continued to improve the product. The Vision line has gone from just being OK to top notch for 1080p (not to mention all the calibration functions included with the Lumagen interface).

craigr

Yep, it sounds pretty good..

But my PC can do the Film mode IVTC and 72hz no problems. 1080i film source material at 1080i 72hz is stunning.
It can't do Pixel Adaptive for Video, but I don't care about video :)

To G90's are just fun to work with. It's like, if something needs to be fixed there is an adjustment to do it.
craigr

Isn't that the truth!! For me they are fun to set up.

Terry

The Lumagen used with the G90 is a Vision Pro HDP with the latest firmware (061706).

Mike

"For 1080I HD playback which has been recorded at 1080I 59.94HZ 1080P 59.94 makes perfect sense."

Terry, a decent HD capable processor should be able to perform IVTC and extract the 23.976fps progressive frames out of the 60i for films. Then you need to play back at a multiple of 23.976. That's why. I run my XG at 1080i 71.928hz for this reason.

1080i 59.94 only applies to very very few TV shows shot interlaced (Sports maybe? Stuff like Lost is progressive).


Mark,

I have had a look at the HD material that is being provided to us via Comcast (a large Cable company here). We are able to stream this HD material to a DVHS Capture program on my computer via firewire (essentially this program make the computer talk to the Comcast HD box via firewire thinking it is a DVHS deck) at it's native (all be it transmitted) rates. It is coming to us at 29.97 fps. I have checked both sporting events as well as movies on HBO and Showtime.
This would imply that 60 Hz is the best refresh rate for us on this.
Granted this is just one provider and what they are doing. But it is natice and when I go to channels that 1080i or 720p the network is changing the resolution to it's native resolution and outputting that on the firewire.

Thought you might find this interesting..

Terry

Terry - as far as I know all broadcast 1080i is flagged at 29.9fps, whether it's really film or not. I'm not at all surprised that you would find this.

So you need a cadence based processor to "see" the 23.976fps base rate, and ignore the flags. This is one reason why IVTC on 1080i material is difficult.

Film is shot at 24fps :)

I Use the Dscaler MPEG2 decoder with 1080i IVTC - it's heavily biased to find film in everything, and it works pretty good for most TS files that I've, umm. acquired. With a standard MPEG2 decoder most of these files report at 29.97fps, when they're really film.

So no, not surprised at all.

Thanks Mark, that sort of clears up what is going on. Looks like I have some more reading to do.

Terry

tse and MP, I've got a question for you...

I'm looking at the datasheet for the LM1283 and I see the following specification.


Three wideband video amplifiers 140 MHz @ −3 dB (4 Vpp output)
What I am wondering is if we really ever come close to using 4 Vpp output? And, assuming we aren’t, may we get better bandwidth response then what is specified in the datasheet.

My thinking is that maybe since the LM1283 isn't being forced to swing 4 Vpp (it's max), that the bandwidth response within the range we are using it in may be better. For instance, if the Vpp used by the G90 is 1.05 Vpp, perhaps within this range the bandwidth capabilities are higher. What do you think?

I read through the LM1283 datasheet pretty thoroughly and didn't find mention of frequency response with respect to Vpp on the output. It seems logical to me that with lower Vpp requirements that the bandwidth characteristics should be better, but maybe I'm off base.

Sony might have been clever here...

craigr

If you look at the Contrast vs Frequency graph you can see the BW vs Output level. At -10db the output is 1.35V. It looks like the BW might be 150 or 160MHz. It's hard to say exactly as the graph is on a log scale.

Scott

I am feeding a Lumagen HDP with 1080i from the Toshiba HD-DVD player and then deinterlacing to 1080p at 48 (47.9?) hz refresh. My screen is only 80 inches wide. The HD-DVD player + Lumagen + G90 produces the best HD image I have seen to date - period! If you haven't seen an HD-DVD image on a good setup then you need to!

Cheers,

Grant

Grant,
Agreed. I tested the HD-DVD player DVI through my scaler, 1080P to G90 last weekend and was pretty amazed at how much better that looked than the 1080i material I get from comcast, which is pretty good.

Terry

Sony might have been clever here...
craigr

It seems that they went with the LM1283 because it was the best way to get OSD, while also being able to control contrast and drive levels. For this easy way to get OSD, they compromised on the best bandwidth perfomance at the time. because there were other chips that had far better bandwidth performance, but they were not so easy to use, and would not have the OSD option built in.

Not sure of their cleverness here, because for some odd ball reason, they seem to have paid more attention to having the best focus peformance and not the best bandwidth performance.

And with a little more effort, they could have done the same thing that Barco did with their Cine and 909. Barco mastered the use of peaking the response beyond the stages rated bandwidth. Why they went that route, is also puzzling. Because they too used a few components that were not the best for bandwidth. The AD835 is rated at 250mhz, while it's big brother (AD834) is rated at 500mhz. I would expect to find the 500mhz big brother in a projector that lists 180mhz as its bandwidth. But again, the big brother needs a few more components to make it do it's thing.

If they (Sony) would have found another way to get the OSD in the video stage, they could have went with better bandwidth options.

On an 50-2035-03P VIM used in the Marquee, the weakest link is rated at 500mhz. That's more like what you'll need to properly get that 1080p/72 through that video chain.

http://www.csgnetwork.com/videosignalcalc.html

Thanks for the input guys.

I'll tell ya what, when I get back to the states at the end of September I'll hook my scope up to the green driver board and see where frequency attenuation begins to become a problem. I for one would like to see if there is attenuation at 1080p 60Hz after the video output amp, right before the signal gets to the CRT. I will of course look at 72 Hz as well.

That way we can see the response of the entire projector and work backwards. It is funny how Sony squeezed the signal so tight... But as you say, it was easy for them that way.

craigr

I'll tell ya what, when I get back to the states at the end of September I'll hook my scope up to the green driver board and see where frequency attenuation begins to become a problem. I for one would like to see if there is attenuation at 1080p 60Hz after the video output amp, right before the signal gets to the CRT. I will of course look at 72 Hz as well.

That way we can see the response of the entire projector and work backwards.

craigr

This would be nice to know. As of the past years, there's much better and cheaper ways to make this all happen better.

I've been working on the driver board for the Barco 808. It's using LM1201's (200mhz) as its control chip. They also have a second set of two LM1201's on the red and blue lines as well. On the second set of LM1201's, they add a peaking network to boost the response thru the second set of LM1201's to maintain the response to the single green channel. This really got my attention, because they needed that second set there for more control options, but they also made sure that kept the best response possible at all three outs from the board. I thought that was clever. And though that driver board in the 808 is not the best bandwidth out there today. With it's early 90's design, it's still one of the best circuits I've seen today.

However, they couple it with the first section (switching board) being the worse thing i've ever seen in video.. :confused:

I've been working on both, but I have a few ideas for the switching board that may also work in the Sony. Since the video section of that switching board is small, I've come up with a mini PC board design that SHOULD correct on the early 1990's limitations becuase of what was out there at the time. On this switcher board they are using a .02 cent video insert circuit to get the text and graphics into the video chain. This is fine for PC signals, but not a good idea for video. But again, what a savings it was. My plan is to use these guys here:

http://www.analog.com/en/prod/0,,768_836_AD8180%2C00.html

To matrix the insert into the video chain, and to do it without any harm to a pure video signal path.

When you get back and check out the video chain in the G90, if that bottleneck does exist at the usable rates, then maybe I can suggest a few ideas to improve on that section. Because there's stuff out there now that could make these sections much better, and it can be done even simpler.

I have a G90 on my look out list with one of my customers.

I've been working on the driver board for the Barco 808. It's using LM1201's (200mhz) as its control chip. They also have a second set of two LM1201's on the red and blue lines as well. On the second set of LM1201's, they add a peaking network to boost the response thru the second set of LM1201's to maintain the response to the single green channel. This really got my attention, because they needed that second set there for more control options, but they also made sure that kept the best response possible at all three outs from the board. I thought that was clever. And though that driver board in the 808 is not the best bandwidth out there today. With it's early 90's design, it's still one of the best circuits I've seen today.Barco 12** (non S) series use fife CA3246E's (1.5 GHz) in place of LM1201's. You should check that design some day, there is still some other places to look at.

One wierd things is that it's driven by same crappy switcher that 808. :rolleyes:

Sometimes the BW spec of ICs is miseading. Like the AD8180 and the claim of >750MHz. That is at an amplitude of 50mV RMS or about 0.14Vpp. With standard 0.7Vpp video the BW is down to 400MHz. The slew rate of 750V/uS limits the part to smaller signals.

Scott

Sometimes the BW spec of ICs is miseading. Like the AD8180 and the claim of >750MHz. That is at an amplitude of 50mV RMS or about 0.14Vpp. With standard 0.7Vpp video the BW is down to 400MHz. The slew rate of 750V/uS limits the part to smaller signals.

Scott

Well, that's really good to know - what would you recommend in place of this?

I have everything else ready. The only thing I'm waiting on now is a good way to multiplex the insert into the video chain, without using the low bandwidth off the shelf digital multiplex chips.

Seemed reasonable to resurrect this thread and see what's new.

[B]

"And comments from various people that a G90 won't "resolve" 1080p 60hz just seems totally ludicrous to me, having seen a G90 at various 1080p refresh rates - it is really SHARP. Especially when there were all sorts of comments about how an XG was "resolving" it the other day (nice work with the XG, but it's not in the same class based on my observations).

If ever get a G90 I damn well will be giving 1080p 72hz a go.


I tried a Crystalio2 on a friends G90. couldn't get 1080P 72Hz running.

heck, I even had problems to get it going with 60Hz.

I remember that someone said that the G90 is really picky when it comes to sync

pulses. anyone can back that claim up ?


Michael

I have my Lumagen outputting 1080P@ 60hz refresh on my G90 and the image is nothing short of spectacular. You might want to check in the service menu what the clamp and sync settings are set to. I had to change it from auto to H/C if my memory serves me correctly.

You should have no issues whatsoever in getting a killer image at 1080p @ 60hz





I tried a Crystalio2 on a friends G90. couldn't get 1080P 72Hz running.

heck, I even had problems to get it going with 60Hz.

I remember that someone said that the G90 is really picky when it comes to sync

pulses. anyone can back that claim up ?


Michael