Modulation frequency in relation to scan speed

[mixedgas]

Keith, design for 100 khz and be happy.
Pangolin and LSX shift the timing in whole point steps, lead or lag.

Steve

[mixedgas]

I should clarify that 100 Khz is a bit of overkill when your software is driving signals through TL082 op-amps and thr scanners have a roughly 3 khz max response.

Steve

[dnar]

Having first built a projector with steppers and microcontroller, plus having also rewritten the laser harp firmware, I have learnt that scanning is actually quite slow and modulation at its worst is still quite fast.

When moving from one beam to another, the scanners move as fast as they can or are tuned without overshooting the mark, although often they do. The modulation is only turns on once the scanners have reached their target position and this requires a short software delay between the scanners stopping and before the beam coming on. This is a user configuration option in Pangolin, tuned in conjunction with the hardware color correction. Any lag in a laser diode, DPSS or driver is compensated for with this adjustable delay.

I feel drivers should specify maximum slew, not frequency. Besides, scan speed alone does not suitably describe the situation, as number of points in a cue and the cue size result in different speed requirements based on complexity.

Also, if you search these forums for my old thread were I posted scope screenshots of the P3 driver, modulation and output traces compared. If I recall correctly, despite the P3 handling high frequency modulation well, slew and phase shift were very pronounced....

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

[Galvonaut]

Thanks Steve - Good to know. I'll try and look into the technicalities of it all as I really don't understand the basics here, of communication between computer and laser via amps and dacs.
Where is the TL082 in the system?

Dnar, thanks, that's interesting. Is there a feedback before the modulation occurs?

At the moment, the Flexmod seems to be the best solution. It is certainly affordable. I will have a look for your posts as I don't really know how slew works (had to check the interwebs)!

Thanks
Keith

[mixedgas]

Just about every scanner amp clone is TLO84 based.
Steve

[dnar]

I hate the TL08x series. Noisy sons of bitches. TL07x are much better.