# Signal Generator vs. AVIA or DVE



## Sonnie

JimP came down to visit yesterday and brought with him an AccuPel signal generator. Pretty neat gadget...










AccuPel link...


He got my Toshiba RPTV looking much better as well as my Z4 projector. 

I contacted Ovation Software (AVIA) and they are discussing an HD version of AVIA, but nothing scheduled or actually in the works for now.

I wouldn't mind having one of these little jiggymadoo's but $1300 is not chump change and I don't really got it right now.

I checked around a little but haven't seen anything near this price. Are there any cheaper signal generators out there that I might be missing? 

I'll probably end up waiting on AVIA or DVE, although DVE's site appears to be down... not sure what their plans are for a new calibration DVD.


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## fibreKid

Okay, I have real weakness for gadgets like this. A signal gen is only half of the equation, what did you guys use for the other half Sonnie? I went trolling around on their web site and it looked like a new toy but I don't know if I would be able to use it. :scratchhead: 

-john


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## Sonnie

Hey john,

I'm not sure I follow you. We had some filters to view through. There was something that JimP mentioned about the grayscale being more exact if he had something with him that he didn't have, but I can't remember what it was. I'm not realy technically savvy with this stuff. I learned quite a bit with Jim, but then there was a lot I didn't really understand.


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## JimP

A spectraradiometer, basically a device that will accurately measure the display and interpet the results scientifically.

Problem is that low cost solution don't work well with the ultra high pressure mercury bulbs that are typically used in LCD and DLP based projectors.

The professional devices run something in the range of $5K to $7K and require a periodic calibration. I've heard of calibrationist who didn't know that they had to have them calibrated, yet noticed that their calibrations always seemed a bit blue. 

Another approach which is stupid simple is to use one of the $125 ish puck solutions to calibrate a CRT computer monitor. They are especially accurate on CRT displays. Display a split grayscale on your computer(jpeg file found on the internet) and a similar one through DVE onto your display(unless your willing to spend for the Accupel). Then its basically an exercise of making the two match. So for grayscale calibration, you are very likely to get a pretty good adjustment. One of the little known secrets is that the human eye is very sensitive to slight differences in color and more accurate at lower IREs than many of the devices that are marketed for display calibrations.


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## JimP

The filters I used over at Sonny's were related to getting color saturation and tint adjusted off of the blue signal. (used the color bar pattern of of the Accupel. Ideally, you also want to adjust color saturation and tint off of green and red as well, provided you can find the settings which are usually burried in the service menu. I use some special filters that kodak makes to better see how the display is responding. The ones that come with Avia and DVE leak some, especially the green one (leaks blue).


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## fibreKid

Ah, Okay. That answers it. 
Thanks much
-john


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## AverageJoe

JimP said:


> The filters I used over at Sonny's were related to getting color saturation and tint adjusted off of the blue signal. (used the color bar pattern of of the Accupel. Ideally, you also want to adjust color saturation and tint off of green and red as well, provided you can find the settings which are usually burried in the service menu. I use some special filters that kodak makes to better see how the display is responding. The ones that come with Avia and DVE leak some, especially the green one (leaks blue).


JP, are those Kodak filters available for retail sale? Do you know where I could get them, and what to ask for?

Thanks.


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## JimP

Joe,

The filters are available from bhphotovideo.com.

The problem is that I wrote the filter numbers on the plastic case I keep them in with a permanent market that subsequently wiped off. I'll try to reconstruct the filter numbers and get back with you.

As a practical matter, the avia filters should work fine. The filters that come with DVE are a bit dark and harder to use because of that.


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## Sonnie

I'll probably want to order a set of those too. They are much easier to use than the AVIA strips.


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## Phil M

Well Sonnie it looks like we're getting you closer towards a caibration:devil: 

You might want to checkout ebay, I toyed with the idea of buying a Sencore signal generator and found a few coming up - but they are not everyday items so you have to be patient.

NB
Can you send Jim up to Pittsburgh?


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## Sonnie

I think Jim is headed up close to your way here pretty soon... maybe he could swing by. 

I haven't thought about ebay for a signal generator... I'll have to keep my eye open there.


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## JimP

Just around the corner in Alexandria Virginia. How far is that??

Been digging around trying to get those filter numbers. Tossed my junk room, folders, emails, etc. Somebody is going to owe me a steak for this. 

Here they are, drum roll please.

92 Red B&H No. K09233 http://www.bhphotovideo.com/bnh/con...ls&Q=&sku=26574&is=REG&addedTroughType=search $57.95

99 Green B&H No. K09933 http://www.bhphotovideo.com/bnh/con...ls&Q=&sku=26577&is=REG&addedTroughType=search $24.95

98 Blue B&H No. K 09833 http://www.bhphotovideo.com/bnh/con...ls&Q=&sku=26574&is=REG&addedTroughType=search $57.95

Also order the plastic frames as these are gel filters you don't want to be holding them in your hand. 

Note that some of these filters are out of stock and will have to be ordered.


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## AverageJoe

JimP said:


> Joe,
> 
> The filters are available from bhphotovideo.com.
> 
> The problem is that I wrote the filter numbers on the plastic case I keep them in with a permanent market that subsequently wiped off. I'll try to reconstruct the filter numbers and get back with you.
> 
> As a practical matter, the avia filters should work fine. The filters that come with DVE are a bit dark and harder to use because of that.


Thanks Jim,
After comparing, I see what you mean about the Avia/DVE difference (Until now I hadn't really looked at the Avia filters. I had only used the DVE filters with both DVD's). If they're larger and not too expensive, it'd still be nice to get the Kodak ones. Thanks for your help.

Joe


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## AverageJoe

Jim,
Oops, I didn't see your post above. Thanks very much.
You're right - I owe you.


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## Sonnie

Reckon why the green is half the price of the red/blue? :scratch:


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## Sonnie

Ouch.... we are talking $96 for a blue filter with the frame... 

Are these the same thing.... ebay

And maybe some less expensive frames here...


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## JimP

A 25b filter doesn't filter the same wavelengths as a 98 Blue. 

Those frame are a bit pricey. Seems like what I got were the Cokin frames that are a little smaller than a 3x3 filter. I had to trim the gel filters down a little.

Don't know why the Green is less than half the price of the others. Since the other two are out of stock, B&H might just be trying to get rid of them.

Something to think about. If you can't get into you color decoder to make adjustments, there's not much point in having anything other than the blue filter which allows you to adjust color saturation and tint based on the blue signal in the user menu.


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## Phil M

Signal generator - someone makes a little USB dongle that generates HDTV test signals, its around $100 or so. I can't recall where I saw it hopefully someone might know? It was a website or maybe ebay?


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## Phil M

Found it:

http://www.markertek.com/Product.as...aseitem=CBUG-HDTV&search=0&off=0&showreturn=1

Any good?


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## fibreKid

Okay, I keep seeing this nifty new gadgets to display various test paterns. ISF classes are quite pricey though. Where does one find out what all the mumbo jumbo means? I don't have 2K to take a class. Any ideas? Even if I don't do any tweeking (just had my set calibrated) I would still like to learn about it.

Thanks much
-john


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## Sonnie

john... I think your only hope would be to purchase some books on it. Trying to piece together all the info scattered about would probably be more confusing than helpful (to me it would be). 

Phil.... 120 bucks... seems almost too good to be true. It has to pass through your computer video card too, I wonder if that would matter. It would be nice to hear from someone who has actually used this successfully.


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## JimP

Phil M said:


> Found it:
> 
> http://www.markertek.com/Product.as...aseitem=CBUG-HDTV&search=0&off=0&showreturn=1
> 
> Any good?



Looks like a jump drive with image and sound files.

Has anyone found a video card with both component and DVI output that will output 480i/p 720p and 1080i/p at both PC and Video brightness levels??


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## lcaillo

I have a little GrandTec unit that I bought for $100 that takes the VGA output from any video card and converts it to 480P, 720P, or 1080i, or PAL. I use it to generate signals for testing and calibration from my notebook pc. Works OK, but the levels may be questionable with a unit at this price. I would not trust them to be precise, though they look dead on for the unit that I have when I check it with a scope.

I chose this because all of my machines are a bit dated and will wait until I upgrade to look at a better video card with HD outputs.

The USB device mentioned is no different than any other file storage. You still need to get the signals out of the computer in the right format.


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## Sonnie

So if I were to get a USB outboard video card with HD output (assuming they make one like this) for my laptop then the USB gadget would work fine?


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## lcaillo

As fine as the output of the card. There are several cards that can do it. I just don't have the horsepower in my machines to bother with HD cards. You can get lots of test patterns that are likely better for free and on DVDs for less $, such as the GetGray DVD, HQV's DVD, the Monster DVD, AVIA, DVE. If you have a card you can just as easily download a file or play a DVD as plug in a USB device. It's the video interface between the copmuter and the display that is more of the problem.


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## Bear5K

Phil M said:


> Found it:
> 
> http://www.markertek.com/Product.as...aseitem=CBUG-HDTV&search=0&off=0&showreturn=1
> 
> Any good?


Phil - It is not worth the money. You can download the ColorFacts signal generator app or the Nokia monitor test app for free. Either of these would provide similar or better functionality.

The issue with PCs as signal generators is that the analog output sections are not very good. Typically, they use 8-bit RAMDACs, which means that they are stretched to output 8-bit video correctly. Matrox posted a chart showing how good their analog output section was vs. ATi and nVidia, and I was personally not impressed with any of them for signal generation purposes.

That being said, DVI is very reliable on PCs, so there is no problem using a PC to generate digital signals for calibration. In fact, in the latest release of CalMAN (v2.02), we have included a basic test pattern generator for speeding up grayscale measurements when used with an HTPC. In our next major release, we will include our full architecture for signal generators, which licensed users will be able to use via add-on licenses (PC-based ones are included for free).

In point of fact, we have now gotten both DVDO and Lumagen to include serial control over their internal test patterns in recent firmware updates at our request. PixelMagic (Crystallio II) has also indicated they will do this (again, per our request which was quickly seconded by several current owners). For HT enthusiasts with a system that includes a video processor, our goal is to be able to directl interface with the included test patterns to obviate any need for an external signal generator.

For folks without a video processor, we are thinking of renting out Accupel's this fall to licensed CalMAN users, but this is not going to be a cheap solution (our target price is $175 for a three-week rental).

Bill


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