ADC with non-linear sensor

[Hayat Qurt]

I have a question regarding ADC . What is the best way ( fastest) to match the reading from the ADC output with non-linear sensor output ?

[HackedFridgeMagnet]

Depends on the mcu and how much memory you have.
If you had lots of ram you use the ADC input which is an integer, as an index into a lookup table.
If you are shorter on ram then you could do the same but make the lookup table (array) smaller and interpolate the point.

[Neilm]

Look at the analogue signal and see if it could be linearised before it reached the ADC

Neil

[PA0PBZ]

Depends on the way it is non-linear of course, maybe you can just calculate the result, just to name another solution.

[ejeffrey]

Lookup table with interpolation if necessary.

[DavidDLC]

Look at the analogue signal and see if it could be linearised before it reached the ADC

Neil

If you can do it by software, save on hardware.


David.

[jmole]

The problem with linearization in software is that you're wasting a ton of bits on data that might not even matter, especially if your signal is logarithmic or exponential in nature.

Check out this app note for details on building a log amp: http://www.analog.com/static/imported-files/tutorials/MT-077.pdf

[nerdyHippy]

Depends on the mcu and how much memory you have.
If you had lots of ram you use the ADC input which is an integer, as an index into a lookup table.
If you are shorter on ram then you could do the same but make the lookup table (array) smaller and interpolate the point.

If speed isn't an issue it's always possible to store the LUT in program memory to save RAM.