[sdiy] Wikipedia DCO article

[cheater cheater]

Ah, so this is the fine distinction!
Thanks a lot for clearing that up.

Cheers
Damian

On Wed, Jan 14, 2009 at 4:55 PM, Scott Nordlund <gsn10 at hotmail.com> wrote:
>
> Well, not to be pedantic, but the DCO integrator is voltage-controlled, the digital part is the CV generation and the reset pulse.
>
> A DAC integrator is just an integrator without a reset pulse, the digital part here is the input, so aside from having an integrator and some sort of digital signal, they're not related at all.
>
> There are 2 integrators in a state variable filter, that doesn't mean it has anything to do with DCOs or anything else using integrators.
>
> ----------------------------------------
>> Date: Wed, 14 Jan 2009 15:44:58 +0000
>> From: cheater00 at gmail.com
>> To: synth-diy at dropmix.xs4all.nl
>> Subject: Re: [sdiy] Wikipedia DCO article
>>
>> 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  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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