[sdiy] Wikipedia DCO article

[cheater cheater]

Well, my point was that NCO's basically output PCM through a DAC, right?
And most DACs are sigma-delta nowadays... so in the end, they use an
integrator, which is pretty much the same thing as a VCO core
integrator. Of course, that's not the point of an NCO, but that is a
tiny tiny way to be able to classify an NCO as a DCO :)


On Wed, Jan 14, 2009 at 3:01 PM, Eric Brombaugh <ebrombaugh1 at cox.net> wrote:
> Tom Wiltshire wrote:
>>
>> On 14 Jan 2009, at 09:52, cheater cheater wrote:
>>
>>> Note that most DACs nowadays are DSD followed by an integrator.
>>> This means most NCO's turn out to be stream synths which means they
>>> are just a whole lot of logic followed by a  classical DCO,
>>> technically speaking.
>>> I'm saying this because I class stream synths as DCO's. Is this right?
>>> Cheers
>>> Damian
>>
>> I thought I was reasonably well informed on the topic, but I'm afraid I
>> have no idea what you're talking about.
>>
>> What's DSD? What's a "stream synth"?
>
> :)
>
> DSD = Direct Stream Digital. This is a marketing term for delta sigma
> conversion architectures and is typically used to describe the data format
> used in audio systems like the somewhat marginalized SACD audio discs. If
> you do a web search on this term you'll find that a fairly large number of
> semiconductor manufacturers (eg TI, etc) are selling parts that
> generate/accept data in this format.
>
> DSD data is basically a 1-bit digital data stream, taken directly from the
> two-level slicer of a sigma-delta ADC. Usually the data rate is ~2.8MHz. In
> order to convert this format to conventional PCM (like a .WAV file) you have
> to integrate it and downsample.
>
> That said, there's really no relationship between NCOs and DSD.
>
> "Stream Synth" is something I can't help with. From context I'd gather that
> this may be another way to describe a fully digital synthesis system, but
> I've never heard it before.
>
> Eric
>
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