[sdiy] 3/4 bit A/D converter (was: Sample&Hold thoughts)

[Grant Richter]

John's used binary weighted resistors. There is a design in Electronotes
that uses an R-2R resistor scheme. One of the best uses I found for this
ripple A/D is to control a CD4089 rate multiplier. It makes a unique
waveshaper and trigger pattern generator. And the bad A/D actually makes it
more interesting.

Would you mind publishing your version of the A/D? I'll wed it to the 4089
and put it up on musynth

> From: sasami at blaze.net.au
> Reply-To: owner-synth-diy at node12b53.a2000.nl
> Date: Fri, 16 Mar 2001 07:34 +0100
> To: synth-diy at node12b53.a2000.nl
> Subject: Re: Re: [sdiy] 3/4 bit A/D converter (was: Sample&Hold thoughts)
> 
> 
>> Johns circuit is more like a neural net. The comparator
> thresholds are
>> modulated by the output state. As such, it is a more like a
> "ripple"
>> converter. There are going to be brief false outputs before
> it settles on
>> the correct answer.
> 
> I designed a circuit very much like this "ripple" one back
> in '80 or '81, and found it to be rather unstable. It
> worked, more or less, but was just too eratic to be of any
> real use. Admittedly I was using 741s.
> 
> Ken
>