Question about Modulation Difference

[claber]

Hi all, can someone explain, what difference has 10kHz analogue modulation and 30 kHz analogue modulation? and how it can affect to the color mixing, can the 10kHz lasers reach 16 millions of colors?

Thanks!

[ElektroFreak]

You won't actually be able to realize anywhere near 16 million colors with any currently available solid state lasers. The 16 million color number is theoretical, and in the real world the modulation characteristics of DPSS and multimode diode lasers make it impossible to achieve. You'll most likely only get several hundred to a few thousand color hues provided your software and hardware will allow it.

As far as maximum modulation rate, it pertains mostly to galvo speed. The faster the laser can be modulated, the better it can keep up with faster galvos, which results in smoother imagery all around. Also, with multicolor systems the modulation rate should be a little higher since the lasers will be modulated faster than in a single color system to create rapid color mixes.

[mixedgas]

Keep in mind your eye only "decodes" about 60 colors at a time anyway.

PCAOM or AO modulation can obtain the 16 million colors, but sadly your eye cant.

The ability to do point to point color is important for corporate graphics shows, but in most cases 10K for color change is not a bad thing.

There is NO industry standard for testing DPSS color, so you have to ask the maker of the laser what their test setup and depth of modulation was.

One cannot just assume a 50% duty cycle square wave.

When evaluating a color system I look for smooth fades and the intensity to be somewhat linear to applied voltage.

Steve

[-bart-]

There really is no standard that defines how modulation parameters should be characterized. So unless specific methodology is mentioned, those figures are pretty worthless.

If color representation is your concern, try to find out the noise levels of the lasers. Lower is better.

[mixedgas]

maybe its time PLers wrote a standard.

Then we kick it over to ILDA.

After all,we are the only ones who seem to care outside of professional laserists.

Steve

[ElektroFreak]

Very true. A standard should be developed that states what the minimum modulation characteristics should be to achieve a given amount of control over color depth. Then lasers could be provided by manufacturers that meet these requirements, while at the same time still providing systems with the same specs we've had all along for those who are less picky.

[mixedgas]

Very true. A standard should be developed that states what the minimum modulation characteristics should be to achieve a given amount of control over color depth. Then lasers could be provided by manufacturers that meet these requirements, while at the same time still providing systems with the same specs we've had all along for those who are less picky.

Easiest test would be a ramp, and a series of spikes of varying width.

Then a test frame.

Steve

[chad]

This sounds like a job for Tockett. He seems to be the pl resident color theory expert.

chad

[tocket]

This sounds like a job for Tockett. He seems to be the pl resident color theory expert.

chad

Unfortunately I know bugger all about DPSS lasers

But I agree that it should be in our interest to try to come up with a standardized test for modulation. As it stands now manufacturers are free to make any claims. They might just as well remove that field from the specifications.

I have thought about a suitable test before, but I think it should be a team effort rather than a one man job. The modulation efficiency thread was something to get it started.

[ElektroFreak]

Agreed. I'd love to help as much as possible, but I lack the necessary software for creating ILDA frames. Using a function generator to experiment with waveforms and responses is no trouble, though, and I have a scope (although it doesn't have any digital storage or export capability) so some experimentation is in order in the near future. I'll happily contribute as much as I can to this cause.

I know that there are others out there with similar equipment or better, so their input woudl be very valuable. I have only 8 DPSS lasers myself, which is not enough to get a good idea of how a large range of lasers behave. We'll need to get an idea of average DPSS modulation response across a large range of lasers to establish a standard.