[PD] [tabwrite4~], is it possible at all?

Charles Henry czhenry at gmail.com
Sun Jan 8 21:23:50 CET 2012

On 1/8/12, Miller Puckette <msp at ucsd.edu> wrote:
> Hi all --
> Peter Brinkmann and Michael Goggins did some related work recently:
> http://nettoyeur.noisepages.com/2010/10/doppler-effects-without-equations/
> but back in the dark ages Barry Vercoe made a Music 11 ugen called 'pipadv'
> that added a signal into a delay line assuming the write location was
> continuous and could be stably differentiated (so that for each point of the
> delay line you could associate a fractional pposition in the incoming
> signal.
> He then interpolated to get fractional-indexed values of the incoming signal
> to correspond with successive sample locations in the delay line, turning
> the problem around backward.)
> I've thought about this for a few hours but so far my only conclusion is
> that
> it's very interesting :)
> Miller

The problems that I see are with orthogonality and reconstruction.  A
sample really just represents a sync that's centered on a point in
time (in the easy case).  Integer numbers of samples are orthogonal...
but the fractionally-centered sample is not orthogonal to samples at
all the integer indexes.

Then, the reconstruction problem follows from it.  When you want to
read a value from a table, does it exactly retrieve the value that was
recorded there?  It seems like the interpolator needs to be modified
continuously with the spacing of adjacent samples.

All I know right now is, I can't spend my whole vacation on a math
problem, even if it's good :)


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