high freq vco

[Magnus Danielson]

From: "Augusto Pinoche" <augustopinoche at hotmail.com>
Subject: Re: high freq vco
Date: Sun, 13 Aug 2000 00:38:52 GMT

> M bachic wrote:
> >The 4046, no, that is strictly a Voltage Controlled Oscilator in the >true 
> >sense of the word.
> 
> No its not, the oscillator core is current controlled,
> in fact its a form of multivibrator.
> It sincs current from a current source/mirror.
> One side looks like a Triangle osc's charge and
> discharge part, two fets open and closing.

You usually don't see this in the datasheet, but there are things like appnotes
;D

> You can use BJ's idea to do a triangle OSC but my
> idea here is why not ty the cap from pin 6 and to gnd
> and pin 7 truh a 10k resistor to +V to get a triangle osc?
> (wonder if i got that right?)

There's a thougth. There is only one way to know - try it!
Drop in a suitable resistor in series with the cap and you have the high end
compensation...

Oh, I did not find BJ's site anymore, I was just about to take a peek at the
4046 based VCO there... Swipnet seems to finally pulled the plug on it.

But naturally you have the schematic, don't you ;D

> Just hook on a expo converter to pin 11 and VCO you go!
> Use the CV input as a lin FM input, or shall we say PM
> input folks?

Um, I think the expo should hit pin 12, not pin 11. Pin 11 shoule be N.C. or
possibly wired to pin 12 just to keep that MOSFET out of buissness.

> Regs from the
> The Dictator

Never knew that the dictator was so hot on DIY Synths ;D

Cheers,
Magnus