[sdiy] dsPICs with DACs: linearizing the 12 bit ADCs, external RAM?

[Tom Wiltshire]

On 7 Jul 2008, at 11:26, cheater cheater wrote:

>>  It is probably overly ambitious to expect usable audio from a 12 bit
>>  ADC,
>
> Some studio reverbs use 12 bit DACs
>> From the 80s...
> still used nowadays, in many self-respecting studios.
>
>> but it one day I will try it out, since it would be so cute to
>>  have ADC, DAC and DSP on a single 28 pin *DIP* package which only
>>  costs a few dollars.
>
> Definitely.
> The question is:
> will the output stage be so shit that you won't be able to use it  
> at all?
> At least some buffering is needed.

I might be misunderstanding you, but...

The output DAC is 16-bit, accurate to 14. This should give reasonable  
audio quality, since that's what it's designed for. It can provide  
output sample rates up to 100KHz.
The ADC *inputs* are where the question is, I thought. That's a  
general purpose 12-bit ADC, designed for sensor measurements and so  
forth. It can provide conversions fast enough for audio, but the  
accuracy is questionable.

As to whether the audio from such a ADC is "usable", that's purely a  
question of perspective. There were plenty of 8-bit sampling systems  
back in the day, and we all thought they were dead futuristic!  
Nowadays, we'd dismiss such a thing as lo-fi retrotech.

Apologies if I did get the stick by the sticky end.

T.