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Thread: My first of A Million questions

  1. #11
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    yeah thats offset.
    here is an excerpt from james howto
    --------------------
    In LaserBoy, from the main menu, option 'b' takes you to wave utilities. First choose option '4' to set up your desired sample shifts.

    If you have a PCAOM, you can take a guess that at 48000 samples per second, your scanners are about 7 samples behind your color modulation, so you can push your scanner signals ahead in time by 7 samples! For sample offsets on X & Y input the digit 7. You do not need to enter zeros for the rest of the list of offsets. You can just [Esc] out of this settings menu. Hit '4' again any time you want to see what your offset settings are and [Esc] to return to the wave utilities menu. If you have a direct modulated diode laser, you might want to try a sample shift of 5.

    If you have a set of lasers that have different modulation reaction times, you can also compensate for differences between the colors!

    Start out with an offset for X & Y of zero. The input negative numbers to indicate how many samples you want to delay each one of the color channels.

    Once you get your desired sample shift list set up the way you want it, you have to apply it to the wave you made earlier. You do this with option '5' apply wave offsets. If you want to return a wave to a state of no offsets between the channels, then set your desired offsets list to all zeros. Since the offsets are stored in the header of the wave, LaserBoy know how to read it in whatever state it is in and rewrite it to any other state you want.

    Once you figure out your offset settings and apply them to the wave, it should be ready to play!

    James.
    ----------------
    http://www.akrobiz.com/laserboy/foru...pic,114.0.html
    Quis custodiet ipsos custodies?
    Solid State Builders Group

  2. #12
    mixedgas's Avatar
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    Leave the RF where it is at. I see you have a nicely equipped lab. Hook the driver input up to 0-1V well filtered DC and slowly ramp the voltage up, and tell me what you see. Dot is nice and clean with the RF off? Is the dot fuzzy with DC? Do you have access to a RF power meter? Any accidental modulation on the +24V to the drivers? It sounds like you are getting RF overdrive or wide sidebands on the signal. One possible source of sidebands is some of these USB dacs oversample and interpolate and dump some near RF crap into the modulator.

    Some of the newer printer drivers have FM as well as AM off the analog input to speed up the on to off transition in the printer, any FM becomes a deflection of the beam.

    Can you get me a shot of the spot on the wall from the hene when modulated on with DC, preferably as far as possible from the AO cell? Not scanned please, just the static dot.

    Did you hunt for the sweet spot in the crystal? Its usually near the piezo transducer that excites the crystal, at the side of the window. What is the arpeture size of the crystal?

    I asked about the hene because if you have multiple lines from the argon, they will spread out in into a spectrum with certain (ie most) AOs. But the hene being monochromatic, will not.

    Steve

  3. #13
    Join Date
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    Default Wow!

    Wow guys, you have given me a lot to tinker with. Thanks soo much. I'll be disappearing down stairs for a few hours to try this stuff.
    I'll try ramping the dc voltage to the aoms and report back, and now that you mention it, the supply im using for the drivers really really sucks. It's a unregulated, old supply, lots of ripple probably, I was planing on making a dedicated supply for it soon..
    In addition I think it is possible some high frequency rf junk from the computer might be riding on the lines.. I'll scope it out..
    And the delay.. makes sense after all the aoms can respond ALOT faster then the galvos. Ok. If no one hears me for over a day.. Call 911 .
    <POOF>
    He runs to the basement in a cloud of smoke.........

    Aceman500

  4. #14
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  5. #15
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    That AO data sheet hints that it really likes focused beams and was designed for speed. Its got a bandwidth of 4x NTSC video if you have the spot size in the crystal less then 80 uM, That should not hurt you for low speed modulation, but the fact that it has a spec for beam ellipse bothers me a bit.I've never seen a spec for that on a AO, and this is one generation newer then any thing I have worked with. So I guess I'm talking to CT tomorrow or the next day about the widget you have.

    Do you have the polarization at right angles to the base, and are you getting at least 50% into the first order?

    The ellipse spec is not in my CT books, but I will email or call them and ask what that means.

    Steve

  6. #16
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    Default The widget

    Thanks so much. Please do go out of your way for little old me!
    Truth be known one of AOM came mounted on a bracket with 2 lenses on either side, and a slit so only the 1st order gets out. Since I fiugured I did not really need the speed and was limited on room so I could remove it. Later I will try it with the bracket back. And to answer your quesiton, as it is im not getting %50 into the first order.. Actually If I paid attention to the spec sheet I would have relized that the beams Im using are just to fat. (like my x-wife).

    And to answer an earlier post:
    Yes I know I can run pong and laseroids, spagehtti and things and am looking forward to playing with that. I don't have windows down there right now but will install it on another drive in the near future. Right now I just want to focus (pun intended) on displaying as best ILDA test pattern I can with what I have; get things tuned up, and get the cleanest, most effecient beam as possible out of my AO's.
    Again guys thanks so much. I ran out to a service call yesterday was unable to mess with all this. Today I should be able to find the time.

    Still alot to do.. T's crossed I's dotted.. Etc..

    Thanks again guys!
    Aceman

  7. #17
    mixedgas's Avatar
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    [quote=aceman500;90070]Thanks so much. Please do go out of your way for little old me!
    Truth be known one of AOM came mounted on a bracket with 2 lenses on either side, and a slit so only the 1st order gets out. Since I fiugured I did not really need the speed and was limited on room so I could remove it. Later I will try it with the bracket back. And to answer your quesiton, as it is im not getting %50 into the first order.. Actually If I paid attention to the spec sheet I would have relized that the beams Im using are just to fa

    No big deal, I still want to know why they go elliptical

    Steve

  8. #18
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    Jul 2008
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    Quote Originally Posted by aceman500 View Post
    . . . I would have relized that the beams Im using are just to fat. (like my x-wife) . . .
    LMAO!!

  9. #19
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    Nov 2008
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    Default Spaghetti

    Download and install Spaghetti free while you still can:
    http://harperingenuities.com/Spaghetti.aspx

    I just got it and it does not seem very free to me?

    Aceman

  10. #20
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    Default

    Quote Originally Posted by aceman500 View Post
    Download and install Spaghetti free while you still can:
    http://harperingenuities.com/Spaghetti.aspx

    I just got it and it does not seem very free to me?

    Aceman
    Looks like you just missed it. When I posted the link 'while you still can' it was 1.8.0.1

    You can still get that version somewhere I'm sure.

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