[sdiy] reducing amount of bits

[Grant Richter]

> This seems like really simple thing to do, but I'm not gettin it yet. Is it
> as easy as NOT allowing the output DAC to see all the available bits and
> just using the top few bits to represent a full scale signal to the DAC?
> 
> For example: If we had a 16 bit word and only used the top four bits ( MSB
> down ) to feed the DAC would that be it?

Yes it is as simple as that. You can use series resistors on the datalines
and a LM3914 Bargraph chip to "short out" bits under voltage control.

This is also what the middle section of a Buchla 266 SOU does for random
voltage levels.