[sdiy] updated web page describing various 'dco' schemes

[cheater cheater]

Ok, I understand the DGO/NCO distrinction now. I guess a counter
outputting pulses itself would be a DGO, since there's no oscillator
core (accumulator cap) to control - therefore it can't be a
'numerically controled' oscillator.

What does 'VDCO' stand for? Seriously, a list that extends all of
those would be useful :)

[a divide-down network is not a DCO]

> btw does anyone know if a synth has been made which uses fixed fast pulses
> to do ya know..a switching power supply kind of scheme to create waveforms?
>   ie. pulsing a LP filter so as to just create an energy distribution that
> approximates the desired waveforms?

Any DAC nowadays. Most prominently advertised with SACD. SACD often
skipped the output lpf, since we can't hear the quantization noise
anyways.

PC Speaker, except they left out the LPF completely and used the
transducer's bad performance at the high end. This worked out to cut
the high tones as well, nicely enough.

I don't know of any 'studio synths' (unless you include any sampler
that has a modern DAC, but that's not really part of the synthesis
architecture)

HTH
D.

On Wed, Jan 28, 2009 at 4:20 AM, Bob Weigel <sounddoctorin at imt.net> wrote:
> Oh yeh I hadn't tried to make the list comprehensive yet by any means.  I
> was mostly just focusing on the DCO categories.    I didn't know nco had
> become formalized terminology.  DGO just seems more intuitively obvious as
> to it's meaning for the novice.  But you're right I should definitely
> mention NCO's as I've heard some talk using the term.  I guess there's an
> order of distinction in that it's possible to digitally generate a signal
> without specifically converting numbers.  Though even with pwm you are doing
> an abstract converstion of numbers still.  It would be good to make that
> distinction also and I'll extend it in that realm.
>
> btw does anyone know if a synth has been made which uses fixed fast pulses
> to do ya know..a switching power supply kind of scheme to create waveforms?
>   ie. pulsing a LP filter so as to just create an energy distribution that
> approximates the desired waveforms?
>
> And the DK600 has an analog VCO which has analog control voltages on the
> front end of the ddn, like Polymoog.  Distinguishing it from machines with
> stable front ends and also digital approximations in pitch control etc.
>  -Bob
>
> cheater cheater wrote:
>
>> I'd add abbreviations like LF and HF.
>> Try to list all abbreviations that you can find (or come up with) with
>> their full versions so that people can learn by example.
>>
>> Also isn't what you call a 'dgo' actually an 'nco'? (you're missing
>> 'nco' on your list btw)
>>
>> I'm not sure what VDCO is or why the Siel DK600 has one, since it
>> simply has a divide-down network (DDN)
>>
>> gtg,
>> D.
>> HTH
>>
>> On Tue, Jan 27, 2009 at 10:21 AM, Bob Weigel <sounddoctorin at imt.net>
>> wrote:
>>
>>>
>>> Let me know if anything needs improvement and if anyway has better
>>> abbreviation suggestions for any of them -Bob
>>>
>>> http://sounddoctorin.com/synthtec/synarch.htm#terms
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