# v_lpcpf2rr

## PURPOSE

V_LPCPF2RR convert power spectrum to autocorrelation coefs RR=(PF,P)

## SYNOPSIS

function rr=v_lpcpf2rr(pf,p)

## DESCRIPTION

    V_LPCPF2RR convert power spectrum to autocorrelation coefs RR=(PF,P)
     Note that these will only be accurate if the power spectrum is much longer than p

## CROSS-REFERENCE INFORMATION

This function calls:

- v_irfft V_IRFFT Inverse fft of a conjugate symmetric spectrum X=(Y,N,D)

This function is called by:

## SOURCE CODE

    0001 function rr=v_lpcpf2rr(pf,p)
    0002 %V_LPCPF2RR convert power spectrum to autocorrelation coefs RR=(PF,P)
    0003 % Note that these will only be accurate if the power spectrum is much longer than p
    0004
    0005
    0006 %      Copyright (C) Mike Brookes 1997
    0007 %      Version: $Id: v_lpcpf2rr.m 10865 2018-09-21 17:22:45Z dmb $
    0008 %
    0009 %   VOICEBOX is a MATLAB toolbox for speech processing.
    0010 %   Home page: http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html
    0011 %
    0012 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    0013 %   This program is free software; you can redistribute it and/or modify
    0014 %   it under the terms of the GNU Lesser General Public License as published by
    0015 %   the Free Software Foundation; either version 3 of the License, or
    0016 %   (at your option) any later version.
    0017 %
    0018 %   This program is distributed in the hope that it will be useful,
    0019 %   but WITHOUT ANY WARRANTY; without even the implied warranty of
    0020 %   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    0021 %   GNU Lesser General Public License for more details.
    0022 %
    0023 %   You can obtain a copy of the GNU Lesser General Public License from
    0024 %   https://www.gnu.org/licenses/ .
    0025 %
    0026 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    0027
    0028 [nf,p2]=size(pf);
    0029 if nargin<2 p=p2-2; end;
    0030 ir=v_irfft(pf,[],2);
    0031 if p>p2-2
    0032   rr=[ir(:,1:p2-1) zeros(nf,p+2-p2)];
    0033 else
    0034   rr=ir(:,1:p+1);
    0035 end