matlab routines for linear predictive coding (lpc).htm

一个非常好的基于MATLAB的语音处理工具箱,对学习语音处理的读者非常有用

      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcdl2aa.txt">aa</A></TD>
    <TD vAlign=top>The <I>discrete cosine transform</I> of the log 
      cross-sectional area function of the tube.</TD></TR>
  <TR>
    <TD vAlign=top width=50>ff</TD>
    <TD vAlign=top width=70><I>p</I>+2</TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcar2ff.txt">ar</A></TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcff2pf.txt">pf</A></TD>
    <TD vAlign=top>The <I>complex frequency response</I> of the AR filter. The 
      first and last elements of ff() are respectively the DC and nyquist 
    terms.</TD></TR>
  <TR>
    <TD vAlign=top width=50>im</TD>
    <TD vAlign=top width=70><I>p</I>+1</TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcar2im.txt">ar</A></TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcim2ar.txt">ar</A></TD>
    <TD vAlign=top>The <I>impulse response</I> of the autoregressive 
  filter.</TD></TR>
  <TR>
    <TD vAlign=top width=50>is</TD>
    <TD vAlign=top width=70><I>p</I>+1</TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcrf2is.txt">rf</A></TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcis2rf.txt">rf</A></TD>
    <TD vAlign=top>The <I>inverse sine</I> coefficients equal sin<SUP>-1</SUP> 
      of the reflection coefficients multiplied by 2/pi to force them to lie in 
      the range +-1 for a stable filter.</TD></TR>
  <TR>
    <TD vAlign=top width=50>la</TD>
    <TD vAlign=top width=70><I>p</I>+2</TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcrf2la.txt">rf</A></TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcla2rf.txt">rf</A></TD>
    <TD vAlign=top>The <I>log area coefficients</I> are the log cross 
      sectional areas of the vocal tract segments. la(<I>p</I>+2) is the log of 
      the effective area of the free space beyond the lips and is normalised to 
      0.</TD></TR>
  <TR>
    <TD vAlign=top width=50>lo</TD>
    <TD vAlign=top width=70><I>p</I>+1</TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcrf2lo.txt">rf</A></TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpclo2rf.txt">rf</A></TD>
    <TD vAlign=top>The <I>log area ratios</I> give the log of the ratio of one 
      tube segment to that of the following segment. These values are limited by 
      the conversion routines to about +-14.5</TD></TR>
  <TR>
    <TD vAlign=top width=50>ls</TD>
    <TD vAlign=top width=70><I>p</I></TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcar2ls.txt">ar</A></TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcls2ar.txt">ar</A></TD>
    <TD vAlign=top>The <I>line spectrum frequencies</I> or <I>line spectrum 
      pairs</I> are normalised frequencies in the range 0 to 0.5. A sharp peak 
      in the AR filter response will give rise to a pair of line spectrum 
      frequencies nearby the peak.</TD></TR>
  <TR>
    <TD vAlign=top width=50>pf</TD>
    <TD vAlign=top width=70><I>p</I>+2</TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcar2pf.txt">ar</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcdb2pf.txt">db</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcff2pf.txt">ff</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcra2pf.txt">ra</A> 
    </TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcpf2cc.txt">cc</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcpf2rr.txt">rr</A></TD>
    <TD vAlign=top>The <I>power spectrum</I> of the AR filter. The first and 
      last elements of ff() are respectively the DC and nyquist terms.</TD></TR>
  <TR>
    <TD vAlign=top width=50>pp</TD>
    <TD vAlign=top width=70><I>p</I>+1</TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcar2pp.txt">ar</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcra2pp.txt">ra</A></TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcpp2cw.txt">cw</A></TD>
    <TD vAlign=top>The <I>power spectrum polynomial coefficients</I>. This 
      polynomial gives the power spectrum of the all-zero inverse filter as a 
      function of cos(w).</TD></TR>
  <TR>
    <TD vAlign=top width=50>ra</TD>
    <TD vAlign=top width=70><I>p</I>+1</TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcar2ra.txt">ar</A></TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcra2pf.txt">pf</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcra2pp.txt">pp</A></TD>
    <TD vAlign=top>The <I>autocorrelation coefficients</I> of the inverse 
      filter's impulse response.</TD></TR>
  <TR>
    <TD vAlign=top width=50>rf</TD>
    <TD vAlign=top width=70><I>p</I>+1</TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcaa2rf.txt">aa</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcar2rf.txt">ar</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcis2rf.txt">is</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcla2rf.txt">la</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpclo2rf.txt">lo</A> 
    </TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcrf2aa.txt">aa</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcrf2ao.txt">ao</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcrf2ar.txt">ar</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcrf2is.txt">is</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcrf2la.txt">la</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcrf2lo.txt">lo</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcrf2rr.txt">rr</A></TD>
    <TD vAlign=top>The <I>reflection coefficients</I> give the relative 
      amplitudes of the incident and reflected pressure waves at the junction 
      between two tube segments. The direction of travel of the incident wave is 
      from the glottis towards the lips. rf(1) is the reflection coefficient at 
      the glottis and rf(<I>p</I>+1) is the reflection coefficient at the lips: 
      both of these coefficients are normally close to 1. Reversing the order of 
      the reflection coefficients leaves the tube transfer function 
  unchanged.</TD></TR>
  <TR>
    <TD vAlign=top width=50>rr</TD>
    <TD vAlign=top width=70><I>p</I>+1</TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcar2rr.txt">ar</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcpf2rr.txt">pf</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcrf2rr.txt">rf</A> 
    </TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcrr2am.txt">am</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcrr2ar.txt">ar</A></TD>
    <TD vAlign=top>The <I>autocorrelation coefficients</I> of the 
      autoregressive filter's impulse response when extended to an infinite 
      number of terms.</TD></TR>
  <TR>
    <TD vAlign=top width=50>ss</TD>
    <TD vAlign=top width=70><I>p</I></TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpczz2ss.txt">zz</A></TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcss2zz.txt">zz</A></TD>
    <TD vAlign=top>The<I> s-plane autoregressive poles</I> are the roots of 
      the <I>AR</I> coefficient polynomial mapped onto the s-plane and expressed 
      in normalised Hz. If ss() is multiplied by the sample frequency, a formant 
      with frequency <I>f</I> and bandwidth <I>b</I> will give an s-plane pole 
      of approximately _b/2 1 jf.</TD></TR>
  <TR>
    <TD vAlign=top width=50>zz</TD>
    <TD vAlign=top width=70><I>p</I></TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcar2zz.txt">ar</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpccw2zz.txt">cw</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpcss2zz.txt">ss</A></TD>
    <TD vAlign=top width=120><A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpczz2ar.txt">ar</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpczz2cc.txt">cc</A>, 
      <A 
      href="http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/txt/lpczz2ss.txt">ss</A></TD>
    <TD vAlign=top>The <I>z-plane autoregressive poles</I> are the roots of 
      the <I>AR</I> coefficient polynomial.</TD></TR></TBODY></TABLE>
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