[sdiy] 3 phase sine VCO

[Roy J. Tellason]

On Tuesday 28 December 2004 12:21 pm, Scott Gravenhorst wrote:
> "Roy J. Tellason" <rtellason at blazenet.net> wrote:
> >On Tuesday 28 December 2004 09:46 am, Scott Gravenhorst wrote:
> >> Also, it was said that only certain CMOS inverters (unbuffered) would
> >> work. Can any of you say whether the venerable 4069UB would work and if
> >> not, why not?
> >
> >The 4069UB _is_ unbuffered...
>
> Yeah, that I know, that's why I asked if this inverter might work as well
> as the one called out in:
>
> http://www.edn.com/article/CA149120.html?spacedesc=designideas
>
> In the article, it mentions something about inverter gain being an issue,
> too much causes the waveform to square up.

You referring to this statement here:

"The concept doesn't work well with normal ac- or HC-buffered gates, because 
they have far too much gain and would drive the nodes into square waves. "

?

The waveform you get out of that is going to be fairly square,  anyhow,  for 
the most part.

If you like,  I have a couple of application notes (pdf format) from Fairchild 
that would seem to bear on this somewhat,  let me know and I'll send 'em to 
you,  or you can snag them from Fairchild's site -- they're AN-118.pdf and 
AN-88.pdf.

Don Lancaster also touches on this sort of thing in his CMOS Cookbook...