[PD] phasor~ and osc~ right inlet: exact timing

Roman Haefeli reduzierer at yahoo.de
Sun Apr 18 16:57:58 CEST 2010


On Sun, 2010-04-18 at 11:25 +0200, Frank Barknecht wrote:
> On Fri, Apr 16, 2010 at 08:19:09PM +0200, Frank Barknecht wrote:
> > Mike's trick then is to take a snapshot~ of the original phasor at the
> > moment of the desired phase resetting.  If you substract that value from
> > the original phasor, you get a phasor~ shifted up or down just by the
> > value it had when the phase was last reset.
> > 
> > Now you can add in the desired phase value again to get a wrap-phasor that is
> > out of sync to the original phasor in exactly the desired fashion.
> 
> Actually I meant two write "take a [samphold~] of the original phasor".
> Taking a snapshot~ or rather, a vsnapshot~ is something I have also
> tried, but it gives the wrong results. See attached example for a
> comparison of [vsnapshot~]->[vline~] with Mike's [samphold~] solution
> (which I simplified a bit). Lesson to learn:  [vsnapshot~]->[vline~]
> won't do what you may expect it to do.

Before this thread was started, I also was thinking of a [vsnapshot~]
based solution. But I didn't even start to try to implement it, because
it includes a loop (message -> audio -> message) that will certainly
introduce a latency, which breaks the goal of accuracy completely. 

I find Mike's loopless [samphold~] based solution very elegant.

Roman






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