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Precise digital gain and offset trimming

Question asked by fjm on Apr 20, 2012
Latest reply on Apr 24, 2012 by jstaley

Hello,

 

We've been tasked with updating an old design that made use of numerous trimming pots in its analog chain to calibrate a sensor.  Essentially controlling DC offset and gain of an AC signal (f < 1 MHz).  The goal is to replace the manual trims with something that can be digitally controlled in order to facilitate easier/quicker sensor replacement.

 

I've seen this sort of thing a couple of different ways: 

1. DAC + analog multiplier

2. DAC + variable gain amplifier

3. multiplying DAC

4. Digital potentiometer

 

Since in some cases we'd like 16-bit resolution, I think we can rule out the digital pots. 

The goal would be to minimize additive noise and ensure the stability of the values while value update rate wouldn't be important. 

 

Can anyone suggest which method would be best for our application.

Or is there another method that I missed - I would imagine this is a very common task.

 

Cheers,

Frank

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