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<HTML>
<HEAD>
<TITLE>TSP (libtsp/SP) - SPecXpc</TITLE>
</HEAD>
<BODY BGCOLOR="#FFFACD">
<H2>SPecXpc</H2>
<HR>
<H4>Routine</H4>
<DL>
<DT>
void SPecXpc (const float ec[], float pc[], int Np)
</DL>
<H4>Purpose</H4>
<DL>
<DT>
Convert prediction error filter coefficients to predictor coefficients
</DL>
<H4>Description</H4>
The error filter coefficients are related to the predictor filter
coefficients by,
<PRE>
ec[0] = 1 (not used)
pc[0] = -ec[1]
...
pc[Np-1] = -ec[Np]
</PRE>
<P>
Predictor coefficients are usually expressed algebraically as vectors with
1-offset indexing. The correspondence to the 0-offset C-arrays is as
follows.
<PRE>
p(1) <==> pc[0] predictor coefficient corresponding to lag 1
p(i) <==> pc[i-1] 1 <= i < Np
</PRE>
<H4>Parameters</H4>
<DL>
<DT>
-> const float ec[]
<DD>
Prediction error (residual) filter coefficients (Np + 1 values). It is
considered an error if ec[0] is not equal to 1.
<DT>
<- float pc[]
<DD>
Vector of predictor coefficients (Np values). These are the coefficients
of the predictor filter, with pc[0] being the predictor coefficient
corresponding to lag 1, and pc[Np-1] corresponding to lag Np.
<DT>
-> int Np
<DD>
Number of predictor coefficients
</DL>
<H4>Author / revision</H4>
P. Kabal Copyright (C) 1997
/ Revision 1.6 1997/10/10
<H4>See Also</H4>
<A HREF="SPcepXpc.html">SPcepXpc</A>,
<A HREF="SPcorXpc.html">SPcorXpc</A>,
<A HREF="SPlsfXpc.html">SPlsfXpc</A>,
<A HREF="SPrcXpc.html">SPrcXpc</A>
<P>
<HR>
Main Index <A HREF="../libtsp.html">libtsp</A>
</BODY>
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