[sdiy] discrete 3-bit AD converter??

[patchell]

    John Simonton (Paia) did this and the article is somewhere in the back
issues of Polyphony.  He made a 4 bit A/D using an LM339 and a bunch of
resistors.  He used this converter to digitize the pots in the Paia Proteus, I
do believe.  I remember the quantization being pretty crude.

    If nobody else can come up with a link, I can scan this and email it to
you.

media at mail1.nai.net wrote:

> This might be a stupid question, but I'm willing to follow it up with an
> even stupider question :)
>
> I'd like to be able to convert a CV going from 0 to 5 volts into a six
> 3-bit binary numbers.  Well, just to illustrate my question, let's just say
> I want four 2-bit numbers to represent one to four volts, such that:
>
> 1V = 00
> 2V = 01
> 3V = 10
> 4V = 11
>
> I'm thinking I could do this with a stack of comparators each set to the
> next highest voltage (off of a "totem pole" voltage divider run off of the
> incoming CV), but I'm thinking there must be an easier way that would use
> less chips.  If that is the best way, is there a single CMOS chip (like the
> opposite of an LED segment driver) that will encode it into a binary
> number??  Are there chips with multiple comparators IC's without the extra
> pins for such a purpose??  Basically, I'm trying to devise a way to enable
> a number of logic states with single control voltage.

--
 -Jim
------------------------------------------------
* Visit:http://www.silcom.com/~patchell/
*-----------------------------------------------
*I'm sure glad Merry Christmas comes just once a year
* -Yogi Yorgensen
------------------------------------------------