[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [ARSCLIST] Sampling Theory (was Fred Layn's post on the Studer list re: Quantegy)
On 16/01/05, Steven C. Barr wrote:
> So...the d/a converter actually creates a smooth waveform rather than
> a set of steps. Is this done by averaging the values of adjacent
> "steps" somehow?
Yes, by applying a steep filter above 22.05KHz. (Nowadays the steps are
doubled or quadrupled in frequency first, so the filter can be more
gentle.)
>
> I had no idea this was done...would the unfiltered signal sound
> essentially the same, or could we hear a distinct difference?
You would hear a difference if your hearing were good above 22.05KHz. On
early players, the very steep filter could have effects in the audible
range.
There would probably also be audible subharmonics of the sample rate
without the filter.
See "Art of Digital Audio" (Watkinson) or "Mastering Audio" (Katz) for
full explanations.
Regards
--
Don Cox
doncox@xxxxxxxxxxxxxx