Re: The long history of Cinematronics and Vectorbeam

On Wed, 26 May 1999 17:51:08 -0700, you wrote:

>> It makes you wonder if you could not use them in a PWM mode. That

>That was the first thing one of the guys where I work suggested. I
>don't know-- I suppose it's do-able, but like you said the operating
>frequency might be tough to synthesize at the required speed (and I

        How high, though, and how much resolution? The PIC16C73's internal
PWM's can generate up to 20KHz (with a 20MHz clock) at 10 bits of
resolution... And I think Microchip has one with a 12-bit PWM now, but I
don't have my product-selection card handy. (I'll try to remember to check
it when I go to work tomorrow.)

>don't know what settling time and transitional behavior would "look"
>like). Ears are pretty forgiving, but eyes might "see" something
>undesirable?

        We're actually trying to do something similar to this at work (not a
vector display, of course, but a PWM driving a MOSFET switch to control the
current to an inductive load)... the biggest problem, aside from the RF
noise (which is a problem for _us_ at the lab, but probably not for what
we're talking about here) is the ringing caused by the inductive load. I'd
think that would cause undesirable squiggles or wavy lines, unless you
could suppress it.
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"An Academic speculated whether a bather is beautiful if there is none
 in the forest to admire her. He hid in the bushes to find out, which
 vitiated his premise but made him happy.
 Moral: Empiricism is more fun than speculation." -- Sam Weber
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Received on Wed May 26 20:35:20 1999