Sequencer Update

[honcho at paia.com]

On Wed, 19 Aug 1998, "jhaible" <jhaible at metronet.de> wrote:
> I originally
>> planned on using John Simontons 4-bit convert 
>> http://www.paia.com/ek7.htm
>
>Looks interesting !
>I just wondered how to build a logic for 16 comparators ...
>but this might be an alternative! Any drawbacks of
>this design? John?
>

None that I can recall. It's a lot simpler than 16 comparators and the 
logic of a 16/4 encoder, for sure. It's difficult to make the scheme 
work for greater than 5 or 6 bits, resistor precision gets to be a 
problem.

The same circuit was used in PAiA's Proteus 1 (not to be confused with 
the more recent synth of the same name from Eu) for digitizing knob 
positions and for digitizing switch positions. Switches switched 
resistors in a simple D/A to produce a voltage corresponding to the 
position of a group of 4 switches. That way all front panel parameters 
were represented by voltages, multiplexed into one of these eK7 
jobbers, and then came out as groups of 4 bit bytes. Sound like a long 
way 'round, I know, but in the greater scheme of things it simplified 
circuitry enormously. 

-John

---------------------------------------------------------
John Simonton                  PAiA Electronics, Inc
3200 Teakwood Ln.              honcho at paia.com
Edmond OK 73013                http://www.paia.com
405-340-6300                   fax 405-340-6378