Exponential ADC

[Magnus Danielson]

From: "Paul Maddox" <paul.maddox at ndirect.co.uk>
Subject: Exponential ADC
Date: Tue, 6 Jun 2000 09:23:32 +0100

> Dear all,

Paul,

>   Heres a good un for you..
> 
>  I want to get an Exponential ADC, ie an ADC that I can scale such that 1V
> increase doubles the value on the output. I would like 16Bit (24 bit would
> be superb!), 14 would be acceptable and I dont think 12bit would do.
> 
>   Short of using an Epoxnential convertor and then driving a normal ADC I
> wondered if anyone had any suggestions?
>   Are there any Exponential ADCs out there? if so where I cant find them.

I do not think there are any unless some oddball trew together an expo
function with an ADC. Either way, expo functions can be done in
digital and guess what, they are not temperature unstable! ;)

I would just use a standard ADC and have a digital expo. If the
receiver of the digital valus is an CPU you could have it calculate
the expo function. If you are unsure how to achieve exponential
funtions in software I could just point you to usefull text.

Cheers,
Magnus