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From: Les Cargill <lcargil...@comcast.com>
Newsgroups: comp.dsp
Subject: Re: Why there are so many bits in sigma-delta audio codec?
Date: Thu, 18 Oct 2012 18:32:32 -0500
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Vladimir Vassilevsky wrote:
> "Les Cargill" <lcargil...@comcast.com> wrote in message
> news:k5osd0$abh$1@dont-email.me...
>
>> It's nice to have the option of 24 bits, but there are vanishingly
>> few cases where you actually get even 96 full dB (16 bits ) of clean
>> input into an ADC.
>
> Good quality audio ADC have dynamic range over 120dB. Instrumental ADCs
> reach over 140dB.
> Despite of those high parameters, ADCs are always a bottleneck and you have
> to switch gears and do all kinds of analog signal conditioning before the
> ADC.
>

It's a heck of a system design to get true 140dB in SNR
from anything, much less something feeding an ADC.


>> SFAIK, fab process and the general ... economics of electronics
>> dictate a standardization to 24 bit ADCs but being in a place
>> to exploit them fully is rare. 2^24 is one big ole
>> number... 16,777,216, aka 144 dB.
>
> If you want to measure something to a resolution of 1%, then 24 bits is mere
> 100dB of dynamic range at best.
>

1% of what? Voltage?

> Vladimir Vassilevsky
> DSP and Mixed Signal Consultant
> www.abvolt.com
>
>
>

--
Les Cargill