162 lines
5.8 KiB
HTML
162 lines
5.8 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
|
|
|
|
<!--Converted with LaTeX2HTML 2002-2-1 (1.71)
|
|
original version by: Nikos Drakos, CBLU, University of Leeds
|
|
* revised and updated by: Marcus Hennecke, Ross Moore, Herb Swan
|
|
* with significant contributions from:
|
|
Jens Lippmann, Marek Rouchal, Martin Wilck and others -->
|
|
<HTML>
|
|
<HEAD>
|
|
<TITLE>Wavetable oscillator</TITLE>
|
|
<META NAME="description" CONTENT="Wavetable oscillator">
|
|
<META NAME="keywords" CONTENT="book">
|
|
<META NAME="resource-type" CONTENT="document">
|
|
<META NAME="distribution" CONTENT="global">
|
|
|
|
<META NAME="Generator" CONTENT="LaTeX2HTML v2002-2-1">
|
|
<META HTTP-EQUIV="Content-Style-Type" CONTENT="text/css">
|
|
|
|
<LINK REL="STYLESHEET" HREF="book.css">
|
|
|
|
<LINK REL="next" HREF="node34.html">
|
|
<LINK REL="previous" HREF="node32.html">
|
|
<LINK REL="up" HREF="node32.html">
|
|
<LINK REL="next" HREF="node34.html">
|
|
</HEAD>
|
|
|
|
<BODY >
|
|
<!--Navigation Panel-->
|
|
<A NAME="tex2html1036"
|
|
HREF="node34.html">
|
|
<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next"
|
|
SRC="file:/usr/local/share/lib/latex2html/icons/next.png"></A>
|
|
<A NAME="tex2html1030"
|
|
HREF="node32.html">
|
|
<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up"
|
|
SRC="file:/usr/local/share/lib/latex2html/icons/up.png"></A>
|
|
<A NAME="tex2html1024"
|
|
HREF="node32.html">
|
|
<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous"
|
|
SRC="file:/usr/local/share/lib/latex2html/icons/prev.png"></A>
|
|
<A NAME="tex2html1032"
|
|
HREF="node4.html">
|
|
<IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents"
|
|
SRC="file:/usr/local/share/lib/latex2html/icons/contents.png"></A>
|
|
<A NAME="tex2html1034"
|
|
HREF="node201.html">
|
|
<IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index"
|
|
SRC="file:/usr/local/share/lib/latex2html/icons/index.png"></A>
|
|
<BR>
|
|
<B> Next:</B> <A NAME="tex2html1037"
|
|
HREF="node34.html">Wavetable lookup in general</A>
|
|
<B> Up:</B> <A NAME="tex2html1031"
|
|
HREF="node32.html">Examples</A>
|
|
<B> Previous:</B> <A NAME="tex2html1025"
|
|
HREF="node32.html">Examples</A>
|
|
<B> <A NAME="tex2html1033"
|
|
HREF="node4.html">Contents</A></B>
|
|
<B> <A NAME="tex2html1035"
|
|
HREF="node201.html">Index</A></B>
|
|
<BR>
|
|
<BR>
|
|
<!--End of Navigation Panel-->
|
|
|
|
<H2><A NAME="SECTION00661000000000000000">
|
|
Wavetable oscillator</A>
|
|
</H2>
|
|
|
|
<P>
|
|
Example B01.wavetables.pd, shown in Figure <A HREF="#fig02.12">2.12</A>, implements a wavetable
|
|
oscillator, which plays back from a wavetable named ``table10". Two new Pd
|
|
primitives are shown here. First is the wavetable itself, which appears at
|
|
right in the figure. You can ``mouse" on the wavetable to change its shape and
|
|
hear the sound change as a result. Not shown in the figure but demonstrated in
|
|
the patch is Pd's facility for automatically calculating wavetables with
|
|
specified partial amplitudes, which is often preferable to drawing waveforms by
|
|
hand. You can also read and write tables to (text or sound) files for
|
|
interchanging data with other programs. The other novelty is an object class:
|
|
|
|
<P>
|
|
|
|
<DIV ALIGN="CENTER"><A NAME="fig02.12"></A><A NAME="2400"></A>
|
|
<TABLE>
|
|
<CAPTION ALIGN="BOTTOM"><STRONG>Figure 2.12:</STRONG>
|
|
A wavetable oscillator: B01.wavetables.pd.</CAPTION>
|
|
<TR><TD><IMG
|
|
WIDTH="554" HEIGHT="194" BORDER="0"
|
|
SRC="img272.png"
|
|
ALT="\begin{figure}\psfig{file=figs/fig02.12.ps}\end{figure}"></TD></TR>
|
|
</TABLE>
|
|
</DIV>
|
|
|
|
<P>
|
|
<BR><!-- MATH
|
|
$\fbox{ $ \mathrm{tabosc4}\sim $}$
|
|
-->
|
|
<IMG
|
|
WIDTH="89" HEIGHT="41" ALIGN="MIDDLE" BORDER="0"
|
|
SRC="img273.png"
|
|
ALT="\fbox{ $ \mathrm{tabosc4}\sim $}">:
|
|
<A NAME="2554"></A>a wavetable oscillator. The ``4" indicates that this class uses 4-point
|
|
(cubic) interpolation. In the example, the table's name, ``table10", is
|
|
specified as a creation argument to the <TT>tabosc4~</TT> object.
|
|
(You can also switch between wavetables dynamically by sending appropriate
|
|
messages to the object.)
|
|
|
|
<P>
|
|
Wavetables used by <TT>tabosc4~</TT> must always have a period
|
|
equal to a power of two; but as shown above, the wavetable must have three
|
|
extra points wrapped around the ends. Allowable table lengths are thus
|
|
of the form <IMG
|
|
WIDTH="50" HEIGHT="29" ALIGN="MIDDLE" BORDER="0"
|
|
SRC="img274.png"
|
|
ALT="${2^m} + 3$">, such as 131, 259, 515, etc.
|
|
|
|
<P>
|
|
Wavetable oscillators are not limited to use as audio oscillators. Patch
|
|
B02.wavetable.FM.pd (not pictured here) uses a pair of wavetable oscillators in series.
|
|
The first one's output is used as the input of the second one, and thus
|
|
controls its frequency which changes periodically in time.
|
|
|
|
<P>
|
|
<HR>
|
|
<!--Navigation Panel-->
|
|
<A NAME="tex2html1036"
|
|
HREF="node34.html">
|
|
<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next"
|
|
SRC="file:/usr/local/share/lib/latex2html/icons/next.png"></A>
|
|
<A NAME="tex2html1030"
|
|
HREF="node32.html">
|
|
<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up"
|
|
SRC="file:/usr/local/share/lib/latex2html/icons/up.png"></A>
|
|
<A NAME="tex2html1024"
|
|
HREF="node32.html">
|
|
<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous"
|
|
SRC="file:/usr/local/share/lib/latex2html/icons/prev.png"></A>
|
|
<A NAME="tex2html1032"
|
|
HREF="node4.html">
|
|
<IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents"
|
|
SRC="file:/usr/local/share/lib/latex2html/icons/contents.png"></A>
|
|
<A NAME="tex2html1034"
|
|
HREF="node201.html">
|
|
<IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index"
|
|
SRC="file:/usr/local/share/lib/latex2html/icons/index.png"></A>
|
|
<BR>
|
|
<B> Next:</B> <A NAME="tex2html1037"
|
|
HREF="node34.html">Wavetable lookup in general</A>
|
|
<B> Up:</B> <A NAME="tex2html1031"
|
|
HREF="node32.html">Examples</A>
|
|
<B> Previous:</B> <A NAME="tex2html1025"
|
|
HREF="node32.html">Examples</A>
|
|
<B> <A NAME="tex2html1033"
|
|
HREF="node4.html">Contents</A></B>
|
|
<B> <A NAME="tex2html1035"
|
|
HREF="node201.html">Index</A></B>
|
|
<!--End of Navigation Panel-->
|
|
<ADDRESS>
|
|
Miller Puckette
|
|
2006-12-30
|
|
</ADDRESS>
|
|
</BODY>
|
|
</HTML>
|