2022-04-12 22:02:59 -03:00
<!DOCTYPE html>
2022-04-12 21:54:18 -03:00
<!-- 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 >
2022-04-12 22:02:59 -03:00
< meta name = "viewport" content = "width=device-width, initial-scale=1.0" >
2022-04-12 21:54:18 -03:00
< TITLE > Prefabricated low-, high-, and band-pass filters< / TITLE >
< META NAME = "description" CONTENT = "Prefabricated low-, high-, and band-pass filters" >
< 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 = "node157.html" >
< LINK REL = "previous" HREF = "node155.html" >
< LINK REL = "up" HREF = "node155.html" >
< LINK REL = "next" HREF = "node157.html" >
< / HEAD >
< BODY >
<!-- Navigation Panel -->
2022-04-12 23:32:40 -03:00
< A ID = "tex2html2903"
2022-04-12 21:54:18 -03:00
HREF="node157.html">
< IMG WIDTH = "37" HEIGHT = "24" ALIGN = "BOTTOM" BORDER = "0" ALT = "next"
2022-04-12 22:02:59 -03:00
SRC="next.png">< / A >
2022-04-12 23:32:40 -03:00
< A ID = "tex2html2897"
2022-04-12 21:54:18 -03:00
HREF="node155.html">
< IMG WIDTH = "26" HEIGHT = "24" ALIGN = "BOTTOM" BORDER = "0" ALT = "up"
2022-04-12 22:02:59 -03:00
SRC="up.png">< / A >
2022-04-12 23:32:40 -03:00
< A ID = "tex2html2891"
2022-04-12 21:54:18 -03:00
HREF="node155.html">
< IMG WIDTH = "63" HEIGHT = "24" ALIGN = "BOTTOM" BORDER = "0" ALT = "previous"
2022-04-12 22:02:59 -03:00
SRC="prev.png">< / A >
2022-04-12 23:32:40 -03:00
< A ID = "tex2html2899"
2022-04-12 21:54:18 -03:00
HREF="node4.html">
< IMG WIDTH = "65" HEIGHT = "24" ALIGN = "BOTTOM" BORDER = "0" ALT = "contents"
2022-04-12 22:02:59 -03:00
SRC="contents.png">< / A >
2022-04-12 23:32:40 -03:00
< A ID = "tex2html2901"
2022-04-12 21:54:18 -03:00
HREF="node201.html">
< IMG WIDTH = "43" HEIGHT = "24" ALIGN = "BOTTOM" BORDER = "0" ALT = "index"
2022-04-12 22:02:59 -03:00
SRC="index.png">< / A >
2022-04-12 21:54:18 -03:00
< BR >
2022-04-12 23:32:40 -03:00
< B > Next:< / B > < A ID = "tex2html2904"
2022-04-12 21:54:18 -03:00
HREF="node157.html">Prefabricated time-varying band-pass filter< / A >
2022-04-12 23:32:40 -03:00
< B > Up:< / B > < A ID = "tex2html2898"
2022-04-12 21:54:18 -03:00
HREF="node155.html">Examples< / A >
2022-04-12 23:32:40 -03:00
< B > Previous:< / B > < A ID = "tex2html2892"
2022-04-12 21:54:18 -03:00
HREF="node155.html">Examples< / A >
2022-04-12 23:32:40 -03:00
< B > < A ID = "tex2html2900"
2022-04-12 21:54:18 -03:00
HREF="node4.html">Contents< / A > < / B >
2022-04-12 23:32:40 -03:00
< B > < A ID = "tex2html2902"
2022-04-12 21:54:18 -03:00
HREF="node201.html">Index< / A > < / B >
< BR >
< BR >
<!-- End of Navigation Panel -->
2022-04-12 23:32:40 -03:00
< H2 > < A ID = "SECTION001251000000000000000" >
2022-04-12 21:54:18 -03:00
Prefabricated low-, high-, and band-pass filters< / A >
< / H2 >
< P >
Patches H01.low-pass.pd, H02.high-pass.pd, and H03.band-pass.pd (Figure < A HREF = "#fig08.28" > 8.28< / A > ) show Pd's
built-in filters, which implement filter designs described in Sections
< A HREF = "node140.html#sect08.low-pass" > 8.3.1< / A > , < A HREF = "node141.html#sect08.highpass" > 8.3.2< / A > and < A HREF = "node143.html#sect8.twopolebandpass" > 8.3.4< / A > .
Two of the patches also use a noise generator we have not introduced before.
We will need four new Pd objects:
< P >
< BR > <!-- MATH
$\fbox{\texttt{lop\~}}$
-->
< IMG
WIDTH="47" HEIGHT="39" ALIGN="MIDDLE" BORDER="0"
SRC="img1014.png"
ALT="\fbox{\texttt{lop\~}}">:
2022-04-12 23:32:40 -03:00
< A ID = "10842" > < / A > one-pole low-pass filter. The left inlet takes a signal to be filtered, and
2022-04-12 21:54:18 -03:00
the right inlet takes control messages to set the
cutoff frequency of the filter. The filter is normalized so that the
gain is one at frequency 0.
< P >
< BR > <!-- MATH
$\fbox{ \texttt{hip\~}}$
-->
< IMG
WIDTH="53" HEIGHT="39" ALIGN="MIDDLE" BORDER="0"
SRC="img1016.png"
ALT="\fbox{ \texttt{hip\~}}">:
2022-04-12 23:32:40 -03:00
< A ID = "10843" > < / A > one-pole, one-zero high-pass filter, with the same inputs and outputs as
2022-04-12 21:54:18 -03:00
< TT > lop~< / TT > , normalized to have a gain of one at the Nyquist frequency.
< P >
< BR > <!-- MATH
$\fbox{ \texttt{bp\~}}$
-->
< IMG
WIDTH="44" HEIGHT="39" ALIGN="MIDDLE" BORDER="0"
SRC="img1017.png"
ALT="\fbox{ \texttt{bp\~}}">:
2022-04-12 23:32:40 -03:00
< A ID = "10844" > < / A > resonant filter. The middle inlet takes control messages to set the center
2022-04-12 23:17:03 -03:00
frequency, and the right inlet to set "q".
2022-04-12 21:54:18 -03:00
< P >
< BR > <!-- MATH
$\fbox{ \texttt{noise\~}}$
-->
< IMG
WIDTH="69" HEIGHT="39" ALIGN="MIDDLE" BORDER="0"
SRC="img1019.png"
ALT="\fbox{ \texttt{noise\~}}">:
2022-04-12 23:32:40 -03:00
< A ID = "10845" > < / A > white noise generator. Each sample is an independent
2022-04-12 21:54:18 -03:00
pseudo-random number, uniformly distributed from -1 to 1.
< P >
2022-04-12 23:32:40 -03:00
< DIV ALIGN = "CENTER" > < A ID = "fig08.28" > < / A > < A ID = "10600" > < / A >
2022-04-12 21:54:18 -03:00
< TABLE >
< CAPTION ALIGN = "BOTTOM" > < STRONG > Figure 8.28:< / STRONG >
Using prefabricated filters in Pd: (a) a low-pass filter, with
white noise as a test input; (b) using a high-pass filter to remove a
signal component of frequency 0.< / CAPTION >
< TR > < TD > < IMG
WIDTH="491" HEIGHT="190" BORDER="0"
SRC="img1021.png"
ALT="\begin{figure}\psfig{file=figs/fig08.28.ps}\end{figure}">< / TD > < / TR >
< / TABLE >
< / DIV >
< P >
The first three example patches demonstrate these three filters (see Figure
< A HREF = "#fig08.28" > 8.28< / A > ). The < TT > lop~< / TT > and < TT > bp~< / TT > objects are demonstrated
with noise as input; < TT > hip~< / TT > as shown is used to remove the DC (zero
frequency) component of a signal.
< P >
< HR >
<!-- Navigation Panel -->
2022-04-12 23:32:40 -03:00
< A ID = "tex2html2903"
2022-04-12 21:54:18 -03:00
HREF="node157.html">
< IMG WIDTH = "37" HEIGHT = "24" ALIGN = "BOTTOM" BORDER = "0" ALT = "next"
2022-04-12 22:02:59 -03:00
SRC="next.png">< / A >
2022-04-12 23:32:40 -03:00
< A ID = "tex2html2897"
2022-04-12 21:54:18 -03:00
HREF="node155.html">
< IMG WIDTH = "26" HEIGHT = "24" ALIGN = "BOTTOM" BORDER = "0" ALT = "up"
2022-04-12 22:02:59 -03:00
SRC="up.png">< / A >
2022-04-12 23:32:40 -03:00
< A ID = "tex2html2891"
2022-04-12 21:54:18 -03:00
HREF="node155.html">
< IMG WIDTH = "63" HEIGHT = "24" ALIGN = "BOTTOM" BORDER = "0" ALT = "previous"
2022-04-12 22:02:59 -03:00
SRC="prev.png">< / A >
2022-04-12 23:32:40 -03:00
< A ID = "tex2html2899"
2022-04-12 21:54:18 -03:00
HREF="node4.html">
< IMG WIDTH = "65" HEIGHT = "24" ALIGN = "BOTTOM" BORDER = "0" ALT = "contents"
2022-04-12 22:02:59 -03:00
SRC="contents.png">< / A >
2022-04-12 23:32:40 -03:00
< A ID = "tex2html2901"
2022-04-12 21:54:18 -03:00
HREF="node201.html">
< IMG WIDTH = "43" HEIGHT = "24" ALIGN = "BOTTOM" BORDER = "0" ALT = "index"
2022-04-12 22:02:59 -03:00
SRC="index.png">< / A >
2022-04-12 21:54:18 -03:00
< BR >
2022-04-12 23:32:40 -03:00
< B > Next:< / B > < A ID = "tex2html2904"
2022-04-12 21:54:18 -03:00
HREF="node157.html">Prefabricated time-varying band-pass filter< / A >
2022-04-12 23:32:40 -03:00
< B > Up:< / B > < A ID = "tex2html2898"
2022-04-12 21:54:18 -03:00
HREF="node155.html">Examples< / A >
2022-04-12 23:32:40 -03:00
< B > Previous:< / B > < A ID = "tex2html2892"
2022-04-12 21:54:18 -03:00
HREF="node155.html">Examples< / A >
2022-04-12 23:32:40 -03:00
< B > < A ID = "tex2html2900"
2022-04-12 21:54:18 -03:00
HREF="node4.html">Contents< / A > < / B >
2022-04-12 23:32:40 -03:00
< B > < A ID = "tex2html2902"
2022-04-12 21:54:18 -03:00
HREF="node201.html">Index< / A > < / B >
<!-- End of Navigation Panel -->
< ADDRESS >
Miller Puckette
2006-12-30
< / ADDRESS >
< / BODY >
< / HTML >
