[sdiy] How does a DCO work?

[Paul Maddox]

Richard,

> I got this. The issue for a PA system is what the clock rate is. Being
> picky, a PA system is still a fixed sample rate system, but for a typical
> hardware implementation the sample rate is very high.

I wasn't aware that PAs were fixed clock rate, what kind of PA are we
talking about?
Mine isn't, but I guess we're not talking about anything less than 10Kw.

> The problem is that there are situations where a PA-like oscillator  - in
> the sense that you have a phasor going round and round based on
accumulated
> phase increments and indexing into a table - is implemented at 44.1, or
> whatever, as happens in some softsynths.

agreed, but its *NOT* a fault of the phase accumulator, its a fault of using
fixed frequency systems.

>  From which there's the suggestion that if DSP based systems upped their
> clock rate well above the current limit of 192kHz, sound quality would
> instantly improve and you'd very likely lose all of the digital crunch and
> grit that mars current implementations.

yep, which is about the only good thing to come from the new Virus, finally
they've upped the sample rate to 192Khz from a pathetic 48khz.

> That's because it is a relative of AM. In any digital system you're always
> modulating your output signal with the sample rate, but the mirrored
> sideband is usually filtered out.

yep, or the sample rate is so high it doesn't matter :-)

Paul