SV: Re: SV: Re: [sdiy] Good 16 bits A/D choice for mono audio recording

[Eric Brombaugh]

Karl,

Good question. Studying the datasheet I see that they're quoting 
+/-15ppm INL which is closer to 16-bit resolution than 24. A bit more 
digging suggests that the part is really only accurate to 18 bits.

So the answer is no - some of those 24 bits are worthless. Audio rate 
codecs aren't much better - 24-bit ADC/DAC combinations are pretty cheap 
these days, but unless you're picking the parts carefully and 
surrounding them with high-quality drivers & supplies you'll never get 
the kind of accuracy that simply counting bits would suggest.

Eric

karl dalen wrote:
> Yes i know, but my question was can these 24 bits be used in practice?
> CMOS process and all kind of internal switching noise?!
> 
> KD
> 
> --- Eric Brombaugh <ebrombaugh at earthlink.net> skrev:
> 
>> Karl,
>>
>> That's true. the ADUC824 has a 24-bit Sigma-Delta ADC on-chip, along 
>> with an 8051 core and a 12-bit DAC. Unfortunately, the sample rate of 
>> the ADC is only about 20Hz at higher resolutions. Useful for precision 
>> instrumentation measurements, but not nearly fast enough for J-P's audio 
>> digitizing application.
>>
>> Eric
>>
>> karl dalen wrote:
>>> Ad has the Aduc series of MCU's some have 24bit sigma-
>>> delta AD but can these 24 bits in practice be realized?