[time-nuts] Help understanding an ADEV

Hal Murray hmurray at megapathdsl.net
Sun Sep 14 02:15:03 EDT 2014

bob at evoria.net said:
> "Note: The DAC module is designed specifically for audio applications and is
> not recommended for control type applications."

> I had hoped that it wouldn't be a problem for driving an OCXO, but my
> mistake.  The datasheet also notes that the DAC has 16-bit resolution but
> only 14-bit accuracy.  It didn't seem to have even that at DC.  The PWM
> version doesn't have any escape clauses.  You set "x" parameters and it's
> supposed to be 16-bits wide.  Maybe "audio" means within the human auditory
> passband? 

In the old days, the specs for DACs and ADCs were easy to understand, at 
least after you figured things out, and all the major vendors had app-notes 
explaining what the parameters meant.  There was INL, DNL and a few buzzwords 
like no-missing-codes and monotonic.

Ballpark of 20 years ago, things got much more complicated.  A new generation 
of chips came out targeted at DSP applications.  FFT plots started appearing 
in data sheets.  Parameters like ENOB (effective number of bits) became the 
important ones.

On top of that, if you are interested in audio or radar, temperature 
stability is not an important parameter.

These are my opinions.  I hate spam.

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