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Thread: TTL question / blanking for beginner

  1. #1
    Join Date
    Apr 2006
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    KENT
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    Default TTL question / blanking for beginner

    Could someone explain simply (to a beginner) how ttl modulation works, is it a varying voltage up to 5v or pulsed at 5v ? also if i had a laser capable of modulation would this be a two wire connection, + the 2 supply voltage wires ?

    what pins on a standard ilda connector would provide the necessary output ? is it better to blank with an additional galvo or TTL ?

    i am new to this an not widely experienced in electronics as you can see, however this has not put me off ordering the necessary scanners, control software and diffraction gratings to have go at my own basic single colour projector.

    appreciate any help.......the gallery looks realy useful re set-ups etc
    .........thanks dave
    dave321

  2. #2

    Default re: modulation

    TTL modulation:

    This is basic on or off state. So the biggest drawback w TTL mod is only 7 colors can be accquired w a whitelight source. Red, green, blue, cyan (B+G) magenta( R+B) & white (R+G+B). 8 colors if you include black :?

    Galvo mod/blanking is prefered over actuator or flags as it is faster and even can be tweaked to give addtional colors...

    But nothing beats direct mod of an DPSS if they have a decent mod circuit, many dont :evil:

    PCAOM's are fantastic, easly to align, but do suffer from effiency loss.
    AOMs basically have all the advantages and disadvantages of PCAOM's except they are usually set up to modulate one color (one color could mean several lines such as the blues and deep blue/violet in an argon) for example split w a dichro, the 514nm green line of an argon laser from the rest of the output, and use one AOM for the green line and one AOM for all the blue lines. Of course this requires additional optical elements, more optical loss, and much more alignment critical.

    So w analog mod the control voltages are not just either on or off, but can be vaired from zero to the upper voltage, and the laser output from the modulator will vary in intensity from zero output to full output. This allows for millions of colors, not just the 7 from TTL mod.

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