180 lines
5.8 KiB
HTML
180 lines
5.8 KiB
HTML
<!DOCTYPE html>
|
|
|
|
<!--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>
|
|
|
|
<meta name="viewport" content="width=device-width, initial-scale=1.0">
|
|
|
|
|
|
<TITLE>Simple formant generator</TITLE>
|
|
<META NAME="description" CONTENT="Simple formant generator">
|
|
<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="node100.html">
|
|
<LINK REL="previous" HREF="node98.html">
|
|
<LINK REL="up" HREF="node97.html">
|
|
<LINK REL="next" HREF="node100.html">
|
|
</HEAD>
|
|
|
|
<BODY >
|
|
<!--Navigation Panel-->
|
|
<A NAME="tex2html2028"
|
|
HREF="node100.html">
|
|
<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next"
|
|
SRC="next.png"></A>
|
|
<A NAME="tex2html2022"
|
|
HREF="node97.html">
|
|
<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up"
|
|
SRC="up.png"></A>
|
|
<A NAME="tex2html2016"
|
|
HREF="node98.html">
|
|
<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous"
|
|
SRC="prev.png"></A>
|
|
<A NAME="tex2html2024"
|
|
HREF="node4.html">
|
|
<IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents"
|
|
SRC="contents.png"></A>
|
|
<A NAME="tex2html2026"
|
|
HREF="node201.html">
|
|
<IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index"
|
|
SRC="index.png"></A>
|
|
<BR>
|
|
<B> Next:</B> <A NAME="tex2html2029"
|
|
HREF="node100.html">Two-cosine carrier signal</A>
|
|
<B> Up:</B> <A NAME="tex2html2023"
|
|
HREF="node97.html">Examples</A>
|
|
<B> Previous:</B> <A NAME="tex2html2017"
|
|
HREF="node98.html">Wavetable pulse train</A>
|
|
<B> <A NAME="tex2html2025"
|
|
HREF="node4.html">Contents</A></B>
|
|
<B> <A NAME="tex2html2027"
|
|
HREF="node201.html">Index</A></B>
|
|
<BR>
|
|
<BR>
|
|
<!--End of Navigation Panel-->
|
|
|
|
<H2><A NAME="SECTION001052000000000000000">
|
|
Simple formant generator</A>
|
|
</H2>
|
|
|
|
<P>
|
|
The next three examples demonstrate the sound of the varying pulse
|
|
width, graph its spectrum, and contrast the waveshaping pulse generator.
|
|
Skipping to Example F05.ring.modulation.pd (Figure <A HREF="#fig06.14">6.15</A>), we show the
|
|
simplest way of combining the pulse generator with a ring modulating
|
|
oscillator to make a formant. The pulse train from the previous example is
|
|
contained in the <TT>pd pulse-train</TT> subpatch. It is multiplied
|
|
by an oscillator whose frequency is controlled as a multiple of the
|
|
fundamental frequency. If the multiple is an integer, a harmonic sound
|
|
results. No attempt is made to control the relative phases of the components
|
|
of the pulse train and of the carrier sinusoid.
|
|
|
|
<P>
|
|
|
|
<DIV ALIGN="CENTER"><A NAME="fig06.14"></A><A NAME="6976"></A>
|
|
<TABLE>
|
|
<CAPTION ALIGN="BOTTOM"><STRONG>Figure 6.15:</STRONG>
|
|
Excerpt from example F05.ring.modulation.pd combining ring modulation
|
|
with a stretched wavetable pulse generator</CAPTION>
|
|
<TR><TD><IMG
|
|
WIDTH="352" HEIGHT="285" BORDER="0"
|
|
SRC="img614.png"
|
|
ALT="\begin{figure}\psfig{file=figs/fig06.14.ps}\end{figure}"></TD></TR>
|
|
</TABLE>
|
|
</DIV>
|
|
|
|
<P>
|
|
The next example, F06.packets.pd (Figure <A HREF="#fig06.15">6.16</A>), shows how to
|
|
combine the stretched wavetable pulse train with a sampled sinusoid to realize
|
|
movable formants, as described in Section <A HREF="node95.html#sect6.carrier">6.3</A>. The pulse
|
|
generator is as before, but now the carrier signal is a broken sinusoid.
|
|
Since its phase is the fundamental phase times the center frequency quotient,
|
|
the sample-to-sample phase increment is the same as for a sinusoid at the
|
|
center frequency. However, when the phase wraps around, the carrier phase
|
|
jumps to a different place in the cycle, as was illustrated in Figure
|
|
<A HREF="node95.html#fig06.07">6.7</A>.
|
|
Although the bandwidth quotient <!-- MATH
|
|
${\omega_b}/\omega$
|
|
-->
|
|
<IMG
|
|
WIDTH="38" HEIGHT="32" ALIGN="MIDDLE" BORDER="0"
|
|
SRC="img588.png"
|
|
ALT="${\omega_b}/\omega$"> must be at least
|
|
one, the center
|
|
frequency quotient <!-- MATH
|
|
${\omega_c}/\omega$
|
|
-->
|
|
<IMG
|
|
WIDTH="38" HEIGHT="32" ALIGN="MIDDLE" BORDER="0"
|
|
SRC="img587.png"
|
|
ALT="${\omega_c}/\omega$"> may be
|
|
as low as zero if desired.
|
|
|
|
<P>
|
|
|
|
<DIV ALIGN="CENTER"><A NAME="fig06.15"></A><A NAME="6986"></A>
|
|
<TABLE>
|
|
<CAPTION ALIGN="BOTTOM"><STRONG>Figure 6.16:</STRONG>
|
|
Using stretched wavetable synthesis to make a formant with movable
|
|
center frequency.</CAPTION>
|
|
<TR><TD><IMG
|
|
WIDTH="361" HEIGHT="373" BORDER="0"
|
|
SRC="img615.png"
|
|
ALT="\begin{figure}\psfig{file=figs/fig06.15.ps}\end{figure}"></TD></TR>
|
|
</TABLE>
|
|
</DIV>
|
|
|
|
<P>
|
|
<HR>
|
|
<!--Navigation Panel-->
|
|
<A NAME="tex2html2028"
|
|
HREF="node100.html">
|
|
<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next"
|
|
SRC="next.png"></A>
|
|
<A NAME="tex2html2022"
|
|
HREF="node97.html">
|
|
<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up"
|
|
SRC="up.png"></A>
|
|
<A NAME="tex2html2016"
|
|
HREF="node98.html">
|
|
<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous"
|
|
SRC="prev.png"></A>
|
|
<A NAME="tex2html2024"
|
|
HREF="node4.html">
|
|
<IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents"
|
|
SRC="contents.png"></A>
|
|
<A NAME="tex2html2026"
|
|
HREF="node201.html">
|
|
<IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index"
|
|
SRC="index.png"></A>
|
|
<BR>
|
|
<B> Next:</B> <A NAME="tex2html2029"
|
|
HREF="node100.html">Two-cosine carrier signal</A>
|
|
<B> Up:</B> <A NAME="tex2html2023"
|
|
HREF="node97.html">Examples</A>
|
|
<B> Previous:</B> <A NAME="tex2html2017"
|
|
HREF="node98.html">Wavetable pulse train</A>
|
|
<B> <A NAME="tex2html2025"
|
|
HREF="node4.html">Contents</A></B>
|
|
<B> <A NAME="tex2html2027"
|
|
HREF="node201.html">Index</A></B>
|
|
<!--End of Navigation Panel-->
|
|
<ADDRESS>
|
|
Miller Puckette
|
|
2006-12-30
|
|
</ADDRESS>
|
|
</BODY>
|
|
</HTML>
|