In Reply to: Re: Circuit that combines 2 x 8-bit ADCs to get 1 higher resolution ADC posted by Ray on 04/27/00 at 7:45 AM:
Ray is only partly correct. A dual slope or any of the other intrinsically linear ADCs (V2F, Sigma-Delta) can be oversampled to produce a higher than native resolution.
But a basic successive approx. ADC cannot, since the linearity of the R2R ladder is only just good enough. I too tried the ramp method and it seemed to work sometimes but that's not good enough.
In order to add dithering noise to "look between the bits" the ADC must be linear between the bits.