poly~ upsampling methods
I just noticed that if I have a poly patch within a parent patch that downsamples by two, it's output is simply the downsampled values repeated.
Ie the sequence 1 2 3 4 5 becomes 1 1 3 3 5 5.
Is there a way to specify how the output of poly is upsampled to produce its output in the parent patch say to get something like 1 0 3 0 5 0 (ie zero padding). Or possible interpolating...
I seem to remember talking with somebody about this a while back but I can't seem to find any info in the forum.
weird, i think poly~ has its own signal vector? check the documentation.
Ok I see what your saying. When you downsample by 2 within poly the signal vector size becomes half of that of the parent patch. I made a workaround by using a count~ to multiply the output of the poly~ so that every second sample is set to zero.
Quote: Tyler Nitsch wrote on Sun, 08 April 2007 21:31
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> Ok I see what your saying. When you downsample by 2 within poly the signal vector size becomes half of that of the parent patch. I made a workaround by using a count~ to multiply the output of the poly~ so that every second sample is set to zero.
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you would have to interpolate it yourself - outside the poly
patcher.
it was about 2 years ago here in the list where someone
gave an example, but i cant find it anymore. it was something
using count~ so that you know where you are ...
Tyler Nitsch schrieb:
> Ie the sequence 1 2 3 4 5 becomes 1 1 3 3 5 5.
which is what you would have to expect, you throw away information...
> Is there a way to specify how the output of poly is upsampled to
> porduce its output in the parent patch say to get something like 1 0
> 3 0 5 0 (ie zero padding). Or possible interpolating...
zero padding would screw your signal completely, why would you want that?...
Interpolating is just a low pass filter of half the samplerate (outside
of the poly~)...
Stefan
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Stefan Tiedje------------x-------
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Hey Stefan,
In a lot of DSP literature they all deal with upsampling thru zero insertion. I was trying to develope a multirate system that was based off of the perfect reconstruction filters. I used haar filters. The idea is to split a signals spectrum in half with the analysis filters... downsample each half and then upsample and filter using the resynthesis filters. Basically a one level realtime wavelet system. When you repeat sample values in the system I created it increases the overall power of the resultant signal which rendered the resythesis part of the patch inaccurate... after doing the zero insertion it worked. Unfortuneatly I cant' get more than one stage to work properly....