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Thread: Blanking "speeds"

  1. #1
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    Question Blanking "speeds"

    welcome to (dumbass 101)

    I have a small inkling about the blanking speed of a dpss laser. 10k, 30, 60k. It can blank nk times a second... correct? and faster is better...

    What speed are shows usually blanking at?
    Love, peace, and grease,

    allthat... aka: aaron@pangolin

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    Not sure what speed shows use, it varies so much, but faster is definitely better. It's not just how many times it can switch on and off in a second, but how fast and cleanly it switches between each state. For fast changes in display, the system is only as good as its slowest parts.

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    I think Maxyz's are rated at 50 KHz. That's .00002 seconds (or 20 microseconds) that it can be turned off and on (if my math is correct, professor )

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    Cool

    There was a thread that talked extensively about this very topic. I don't have the time to dig it out right now, but if you've got some time to play with the forum search engine you should be able to find it.

    Bill Benner made a good point in that without a standard, the blanking speed is a useless spec. For example, lots of analog lasers claim that they can blank at 10Khz. Ok - blank to what? Is that full-on to full off in 1/10,000th of a second? And what about the full-off to full-on time? (Which is more important in a DPSS laser.) What about power loss for the first few miliseconds following an up-power transient? (Yeah, we're talking about jellybeaning here.) At what power level is the laser considered to be "on"? How much variation is allowed? The laser industry hasn't specified any standard for these measurements, so it's hard to compare them.

    Having said all that, I've played with lasers that are rated for 10Khz blanking (whatever the hell they really mean by that is anyone's guess), and discovered that they will work OK for speeds up to around 24Kpps. For 30Kpps and faster, you really want 15Khz or 20Khz blanking. (My blue laser is rated at 15Khz, and it does just fine.) This does not address jellybeaning, however. (Both my blue and my green laser exhibit this blanking-induced power loss to some degree when the blanking speed gets up really high.)

    Marconi's Maxyz modules are conservatively rated at 50Khz, and that is the worst case scenario (full-off to full-on, or at least to 90% of full power.) If all lasers could match his specs, we wouldn't have a problem. Alas, don't hold your breath. His specs are hard to match, especially in a DPSS laser.

    Also, in my projector it's very obvious that the Maxyz modules are faster than the other DPSS lasers. (You can see it in some patterns - the red leads the other colors.) One of these days I'm going to build the delay circuit that Bill Benner posted so that all three lasers will have the same blanking delay...

    Adam

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    [QUOTE=Buffo;29202]There was a thread that talked extensively about this very topic. I don't have the time to dig it out right now, but if you've got some time to play with the forum search engine you should be able to find it.

    See my post entitled "back from SELEM and Disgusted"

    Steve Roberts

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    [quote=mixedgas;29204]
    Quote Originally Posted by Buffo View Post
    There was a thread that talked extensively about this very topic. I don't have the time to dig it out right now, but if you've got some time to play with the forum search engine you should be able to find it.

    See my post entitled "back from SELEM and Disgusted"

    Steve Roberts
    This is the first time I have found the chance to use this one... If anyone is offended, research the forum I got it from... (the fam)


    I tried... I'm a and don't get a lot of what you mean... although I got the discussion at SELEM. I also think you guy skipped over my "?"... except The_Doctor... What speeds are the shows, say included with Pangolin, blanking the lasers at?

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    Allrighty then ..
    Here's my take on it. I may be way off base, in which case I'm sure somebody will chime in.
    I think blanking is variable according to what's being projected- e.g. a square inside a circle inside a square. The smaller line will have to be a lot shorter time period than the larger one. Without going into slew rates and dv/dt stuff i suffice it to say that the 50Khz will be able to blank alot faster and turn off /on the beam quicker than a 10KHz
    Attached Thumbnails Attached Thumbnails BLANKING.JPG  


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    Thank goodness for AOM's and PCAOMS

    Mark

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    [QUOTE=allthatwhichis;29247][quote=mixedgas;29204]

    This is the first time I have found the chance to use this one... If anyone is offended, research the forum I got it from... (the fam)

    No offense, I got the point!

    guy says, the schizzle is 30K point by point blanking is roughly 50 khz like da man sayz, Buffo is da man, .00033 seconds a point. So a single pangolin point is gotta turn on and off in .00030 seconds, give or take a zero. 1 divided by the
    PPS = the point time in seconds.

    "we loves us to fly and it shows"
    You had to be at selem to understand that.

    if anyone is offended, to hell with politically correct! I treat everyone the same.

    Steve
    Last edited by mixedgas; 09-07-2007 at 14:25.

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    Quote Originally Posted by ImageLight View Post
    Thank goodness for AOM's and PCAOMS

    Mark
    yeah and I'm willing to bet most of the chinese blues and some chinese greens everybody has trouble modulating are actually polarized,and would work fine with a isomet 1205 AOm or similar. should checked that when I was at SELEM. If its YVO4 and Not pure Nd:yag, its inherently polarized.

    Remind me folks to fedex a polarizer to FLEM.

    Steve Roberts

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