>> >> lookup table in the PIC with linear interpolation
>> between the two points
>
>> >> where the ADC value landed. Accuracy is better
>> than 0.1degree C or
>> >> 0.1degree F in the temperature range of interest
>> (90 to 110 degrees F).
>
> Hi Harold,
>
> If all the needed range for accuracy was between 90
> and 110, why not use an opamp and the internal 10 bit
> ADC? You can feed the unamplified signal to another
> channel, so you get rough temperature, and the amped
> channel with 1000 points gets you better than .05
> degree resolution.
>
> Opamp and a few good resistors will cost you a lot
> less than a 20 bit ADC.
>
> Cheerful regards,
>
> Bob
>


I like to minimize parts count. Each of those other parts would contribute
error. Dunno if it was the optimum design, but I like the way it turned
out. A 20 bit sigma delta ADC is not too expensive.

Harold
(The ideal design has zero parts)

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