[sdiy] Wikipedia DCO article

[Scott Nordlund]

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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