Modulation frequency in relation to scan speed

[Galvonaut]

A few questions for the clever folks of PL please...

I would like to know how diode modulation speed relates to accurate scanning and at what frequencies a difference may be noticed in scanning, if at all? Is accurate modulation also limited to the frequency at which the diodes can actually modulate in themselves?

Is there a noticeable difference in colour pallet with modulation speed?

Do PCAOMs modulate faster than a diode is capable of?


Thank you.

Keith

[badger1666]

learning material for you http://www.photonlexicon.com/forums/...-at-high-speed

[Galvonaut]

learning material for you http://www.photonlexicon.com/forums/...-at-high-speed

Thank you! My search was pretty futile :P

Keith

[Galvonaut]

Ok, that answers a few questions

Need more input! I haven't read Sam's Laser FAQ since before I built my first 500mW green PJ, so will understand more now!

Keith

[mixedgas]

Keith,

PCAOM, 100-200 KHz rated, actually can go much faster, say 1 Mhz. EO modulator, a few 10s of Mhz. AO modulator, up to 7-10 MHz or more. Diode, about 1-2Mhz with a cheap driver, much, much, much, more with a professional driver.

Take 1/pps and that Is your point period or time in seconds. It Is wise that your color modulation be as fast as the point time, but you can get away with it being a fraction of that. Say 3 times the point period or time. Which is why you see DPSS green rated at 10 KHz for 30Kpps shows.

In reality, color can be very slow, ~1 KHz in older galvo blanked systems.

Let the fighting begin, as I just used some very generalized numbers.

Steve

[sbk]

I was worried that the 400kHz ADC sampling frequency of my (currently under dev) advanced color correction board would not be enough to capture the incoming color signals with sufficient accuracy, but if the 1/pps formula is correct, it should work like a charm, not?

Take 1/pps and that Is your point period or time in seconds. It Is wise that your color modulation be as fast as the point time, but you can get away with it being a fraction of that. Say 3 times the point period or time. Which is why you see DPSS green rated at 10 KHz for 30Kpps shows.

In reality, color can be very slow, ~1 KHz in older galvo blanked systems.

Let the fighting begin, as I just used some very generalized numbers.

Steve

[Galvonaut]

Thanks Steve.

Do specific drivers operate better at certain frequencies (like radio) and can they be matched to a particular galvo speed?

Does an order of magnitude faster modulation improve scanned effects at all?

Swami mentioned that faster modulation is a good thing when I asked about diode drivers but I don't really understand how modulation is linked to the galvo output. I am imagining that modulation is one dimension of the 'resolution' if you like, with XY points being the other?

I note that when tuning colour modulation with scanning, the signal is advanced or retarded to avoid tails etc. Is this the only improvement that can be made to scanner output?

More and more questions all the time

Keith

Keith,

PCAOM, 100-200 KHz rated, actually can go much faster, say 1 Mhz. EO modulator, a few 10s of Mhz. AO modulator, up to 7-10 MHz or more. Diode, about 1-2Mhz with a cheap driver, much, much, much, more with a professional driver.

Take 1/pps and that Is your point period or time in seconds. It Is wise that your color modulation be as fast as the point time, but you can get away with it being a fraction of that. Say 3 times the point period or time. Which is why you see DPSS green rated at 10 KHz for 30Kpps shows.

In reality, color can be very slow, ~1 KHz in older galvo blanked systems.

Let the fighting begin, as I just used some very generalized numbers.

Steve

[Galvonaut]

Would using something like this driver(PDF) with upto 1Ghz analogue modulation make any difference in comparison to using flexmod (other than the huge price difference)?

Keith

[dnar]

I don't see driver slew being a big issue, as modulation is skewed in Pangolin software as a setting, plus color correction if you have it.

[Galvonaut]

I don't see driver slew being a big issue, as modulation is skewed in Pangolin software as a setting, plus color correction if you have it.

Merry Christmas dnar!

This is something I don't really know anything about. I got a bit lost in Sam's Laser FAQ the other day trying to figure out how modulation works in combination to scanning.

I'll be using LSX, so not sure how skewing/slewing? compares to Pango.

Keith