[sdiy] The Visible VCO

[René Schmitz]

Hi John and List,

> Maybe I should have written "The Visible Oscillator." I was playing on
> the name of the plastic "Visible Man" models.

Something where I am lost, being on the other side of the pond... :-P

> But... but... doesn't that Frequency Vernier adjust the voltage? It
> looks to me like a VCO without a CV input.

Its roughly defining the current.

> What about the Retrace Balancing Signal, maybe that's for high
> frequency compensation?

Its to blank out a CRT. All in all this is the timebase for a scope or 
something. Or maybe just the timebase for a "wobbler". In either case 
the retrace blanking signal would go to the luminance ("Z") input of the 
scope (-tube).
I would say this was used in schools for demonstrations.

> So it's a sawtooth with curved slopes? What's the frequency spectrum
> of that? (Magnus!!) I wonder, though, because a linear sweep generator
> is a lot more useful.

Hmm, if the thresholds are closely together, i.e. the amplitude is 
small, and so the vernier-resistor approximates a current source, the 
slope could be almost linear.

Cheers,
  René

-- 
uzs159 at uni-bonn.de
http://www.uni-bonn.de/~uzs159