On Saturday 30 June 2012 15:52:13 Grant Edwards wrote: > On 2012-06-30, Peter Humphrey <[email protected]> wrote: > > The displays were graphic stroke writers, as used in submarines and > > other warships - none of that nasty raster technology. I think the > > display drivers were more complex than the CPUs - all that D-A > > conversion of multiple values at once. Can you imagine X and Y > > amplifiers to drive a spot in a circle - and meet up? > > That's actually pretty trivial: Feed a sine wave into X and cosine > into Y. AC amplitude controls size, DC offsets control position. > Hint: cosine is just sine phase shifted by 90 degrees, so you can do > that with a single resistor and capacitor.
Hmm. Hadn't thought of doing it that way. Neat. > > Then a display full of them. > > Been there, done that. :) :-) -- Rgds Peter
