VW said:
[quote author=andy_con link=1214073152/12#12 date=1214154844]what does matter is analogue modulation.
Could you elaborate on that a little? From what I've learned the past months I haven't read much on the subject...[/quote]
When dealing with modulating lasers, you can have TTL (digital) modulation, or analog modulation. With TTL modulation, its just like having a light switch. You send the laser an input signal that's either 0V or 5V. At 0V the laser will be fully of, and at 5 V it will be fully on (or vice versa) - there's no in between. On the other hand, with analog modulation 0 and 5V may still correspond to full off and on, but you also get everything in between - 2.5V would be 50% output, 4V is 80%, etc (this is in an ideal, perfectly linear world. Normally things aren't so wonderfully linear though unfortunately)
TTL modulation is normally faster than analog, but the advantages to analog are vast. IE, if you had an RGB with TTL, you only have 7 color options. Fast enough switching, and you can simulate a few more perhaps, but that's it. With analog, you get everything - an infinite array of every color possible with a mixture of red, green, and blue. Therefore, analog modulation is typically a bare minimum requirement for any modern lasershow work. (similar results used to be achieved on gas lasers with modulatable crystals called AOMs, and its still possible to modulate DPSS lasers via AOMs, but its typically easier and cheaper to purchase units with built in analog)
VW, can you PM me the requirements of the lasers you're looking for, a general idea of your budget, and what type of time frame you're hoping to work on? I may be able to get you a good deal on some pretty awesome modules, and I'm always up to offer whatever help I can. I've worked on my own RGB in the past, but the slew of decision eventually cut the project short. Hopefully I can at least pass of what I've learned so others don't have to make the same dumb mistakes I have.