Prev: Repairing expensive speakers
Next: Non linear amplifier output
From: Vladimir Vassilevsky on 9 Jul 2010 11:39


Phil Hobbs wrote:

>>> Using a ratiometric measurement I can get rid of this, ideally, so
>>> I'm left with the intrinsic 1/f noise of the ADC and DAC.
>>
>> There is no 1/F in the chopper stabilized ADCs.
>>
>>> Does anybody have any wisdom about the intrinsic 1/f noise of ADCs
>>> and DACs?
>>
>>
>> Check ADS1282 from TI. This state of the art ADC has the noise floor
>> of ~5nv/root(Hz) all the way down to DC.
>
> This sensor uses an interferometer rather than coils or piezos, so we
> start out with a sensitivity advantage--even with the AD7699, our
> sensitivity is quite adequate in the white noise region, so if the 1/f
> can be controlled, we should be in good shape.

Chopping generally increases noise floor but in the 1/F area. I don't
know how to estimate chopping noise, however the typical figures for
choppers are ~20nV/root(Hz). The 5nV/root(Hz) of ADS1282 is outstanding;
don't know how hard it would be to achieve that with a home made circuit.

Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com

First  |  Prev  | 
Pages: 1 2 3 4 5 6
Prev: Repairing expensive speakers
Next: Non linear amplifier output