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Re: Inter/Extrapolation

Date1999-05-17 01:00
FromFabio Bizzetti
SubjectRe: Inter/Extrapolation
At 16.23 15/05/99 -0400, you wrote:
>> > I dunno about this specifically, but one other "perfect
>> > interpolation" would be to compute the DFT/FFT of the
>> 
>> NO.  You'll get a perfect interpolation of a hypothetical 
>> periodic signal of which the FFT is the transform.  That
>
>argh. i edited this sentence so often that it ended up being 
>wrong...  Right is that an n-point IDFT will give you an n-point 
>signal, just as an DFT of an n-point signal will give you--you 
>guessed it--an n-point DFT.  Hence, you will still need to interpolate.

Why?
You can compute the position (yes, fractional) of the IDFT at
any single sample.. just use additive sinusoidal synthesis. I guess
you misunderstand what I mean with inverse FT, with a whole IDFT.


>-Tobias 



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Date: Mon, 17 May 1999 09:09:44 +0800
From: Lonce LaMar Wyse 
Organization: Kent Ridge Digital Labs
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Hi Rinaldi,

 > I'm working on CSound but still most of my time goes to "analogic"
music: I
 > play piano, oboe and english horn.

Interesting term "analogic" music.  - I suppose there is an analogy to
be made between the art people used to make using only notes and what we
now understand to be music!

- lonce




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Date: Sun, 16 May 1999 23:46:58 -0400
From: Tobias Kunze 
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To: Fabio Bizzetti , csound@maths.ex.ac.uk
Subject: Re: Inter/Extrapolation
References: <4.1.19990515125434.0092e4e0@212.216.176.64>
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> You can compute the position (yes, fractional) of the IDFT at
> any single sample...

Im not sure i understand what you mean with "computing the 
fractional position of the IDFT".  IDFTs don't have "positions".  
Windows (ie, window centers or window "corners") may be at a 
certain sample index within a sound file, but that's completely
irrelevant to their definition.  Furthermore, both, the DFT and 
IDFT are (as the "D" in their name indicates) discrete operations 
and thus can't be "positioned" fractionally unless you sample 
rate convert the signal in the first place, which, I believe, 
was the whole point of this discussion.


> just use additive sinusoidal synthesis.

An IDFT takes frequency-domain data and returns a time-domain signal.
Period.  No need for additional additive synthesis. 


> I guess
> you misunderstand what I mean with inverse FT, with a whole IDFT.

I am talking about

           N-1
        1  ---     jtk2pi/N
  x  = --- >    X e
   t    N  ---   k
           t=0

and about the fact that a DFT only not distort the signal iff it is
harmonic (truly and infinitely periodic).  Hence, it is unsuitable
for sample-rate conversion.

And, yes, it is not quite clear to me what you are talking about.


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>Lonce LaMar Wyse  re : Rinaldi 
> > I'm working on CSound but still most of my time goes to "analogic"
>music: I
> > play piano, oboe and english horn.
>
>Interesting term "analogic" music.  - I suppose there is an analogy to
>be made between the art people used to make using only notes and what we
>now understand to be music!
>
>- lonce


what does lonce now understand to be notes +?



!we
!!




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To: csound@maths.ex.ac.uk
Subject: [ouch] programme notes
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http://www.5.co.nz








     0
    / \
   1   3
    \   \
     2   4

+ would an! kare 2 pred!kt outkom ov patch. b.lo +?















































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setlanguag(engl!sch);
humanz.onerror = null;
nein = new Nato();

Ring around the rosy,
Pockets full of posy
Ashes, ashes,
Nato ___..


estingi estingigi malestingi malestingigi ekmalestingi
ekmalestingigi si yo vell har considerat it falsmen quam
intransitiv


setlanguage(null);
humanz.onerror = engl!sch;
new Nato() = nein;




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Date: Mon, 17 May 1999 18:40:52 +1000
To: csound@maths.ex.ac.uk
From: Terry McDermott 
Subject: Re: ampdb
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one last word...

A small discrepancy such as the ampdb description probably should be
pointed out to the whoever is doing the manual or the csound book proo
freading...  I think it may be able to be reported to David Boothe... is
that correct?

>Anyway, it's clear that the manual is not precise, misleadingly stating that
>the reference is 90dB = 32000.
>Even if the deviations are insignificant, as I said, it's always better to
>have a good idea of how opcodes work and known exactly what to expect.
>
It is often the tiniest discrepancies that cause the greatest confusion....


Terry McDermott

Music Department
School of Arts & Media
Latrobe University
Bundoora, Victoria, 3083
Australia

email: T.McDermott@latrobe.edu.au

Telephone	+61 3 9479 2167
Fax		+61 3 9479 3651




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Subject: taninv2
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Hello list!
Whoever happens to need the taninv2 opcode may be interested in the following.
Two days ago, I wanted to use a Csound statement like this:

ablah     =         taninv2(afoox,afooy)

I'm using version 3.52 and I followed the Windows online help which explains
the opcode.
But - it's a syntax error!
After inspecting the source code, I found that the correct syntax is:

ablah     taninv2   afoox,afooy

Happy again,
Jens Groh



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Date:     Mon, 17 May 99 12:12:27 BST
From: jpff@maths.bath.ac.uk
Subject:  Version 3.54 Almost ready
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Message written at 17 May 1999 12:04:28 +0100

I have 3.54 working now, English only, on SGI, Linux and PC.  I will
arange distributions tomorrow, as i am rather late this morning, and I
do not yet have release notes.
  Apart from two minor opcodes the main changes are for languages.
Also some minor language changes.  More notes will follow.

I will be mailing privately to those who offered to assist with
translations.  I suspect that is a tedious job; there are over 1420
messages in Csound.

==John ffitch