<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML> <HEAD> <TITLE>void FIR_double_filter</TITLE> <META NAME="GENERATOR" CONTENT="DOC++ 3.4.6"> </HEAD> <body bgcolor="#ffffff" link="#0000ff" vlink="#dd0000" text="#000088" alink="9000ff"> <A HREF = "http://www.cstr.ed.ac.uk/"> <IMG align=left BORDER=0 SRC = "cstr.gif"></A> <A HREF="http://www.cstr.ed.ac.uk/projects/speech_tools.html"> <IMG BORDER=0 ALIGN=right SRC="est.jpg" width=150 height=93></A> <br> <br clear=left> <p align=right> In file ../include/sigpr/EST_filter.h:<TABLE BORDER=0><TR> <TD VALIGN=TOP><H2>void <A HREF="#DOC.DOCU">FIR_double_filter</A></H2></TD><TD><H2>(<!1><A HREF="EST_Wave.html">EST_Wave</A> &in_sig,<BR> <!1><A HREF="EST_Wave.html">EST_Wave</A> &out_sig,<BR> const <!1><A HREF="EST_FVector.html">EST_FVector</A> &numerator)</H2></TD></TR></TABLE> <BLOCKQUOTE>General purpose FIR double (zero-phase) filter.</BLOCKQUOTE> <A NAME="DOC.DOCU"></A> <HR> <H2>Documentation</H2> <BLOCKQUOTE>General purpose FIR double (zero-phase) filter. This function will double filter the waveform <TT>sig</TT> with a previously designed filter, given as <TT>numerator</TT>. The filter coefficients can be designed using one of the designed functions, e.g. <!1><A HREF="design_FIR_filter.html">design_FIR_filter</A>. Double filtering is performed by filtering the signal normally, resversing the waveform, filtering again and reversing the waveform again. Normal filtering will impose a lag on the signal depending on the order of the filter. By filtering the signal forwards and backwards, the lags cancel each other out and the output signal is in phase with the input signal. <P></BLOCKQUOTE> <DL><DT><DT><B>See Also:</B><DD><!1><A HREF="design_FIR_filter.html">design_FIR_filter</A>, <!1><A HREF="design_lowpass_FIR_filter.html">design_lowpass_FIR_filter</A>, <!1><A HREF="design_highpass_FIR_filter.html">design_highpass_FIR_filter</A>, <BR><!1><A HREF="FIRfilter.html">FIRfilter</A>, <!1><A HREF="FIRlowpass_filter.html">FIRlowpass_filter</A>, <!1><A HREF="FIRhighpass_filter.html">FIRhighpass_filter</A> <BR><DD></DL><P><P><I><A HREF="index.html">Alphabetic index</A></I> <I><A HREF="HIER.html">HTML hierarchy of classes</A> or <A HREF="HIERjava.html">Java</A></I></P><HR> <A HREF = "http://www.ed.ac.uk/"> <IMG align=right BORDER=0 SRC = "edcrest.gif"></A> <P Align=left><I>This page is part of the <A HREF="http://www.cstr.ed.ac.uk/projects/speech_tools.html"> Edinburgh Speech Tools Library</A> documentation <br> Copyright <A HREF="http://www.ed.ac.uk"> University of Edinburgh</A> 1997 <br> Contact: <A HREF="mailto:speech_toolss@cstr.ed.ac.uk"> speech_tools@cstr.ed.ac.uk </a> </P> <br clear=right>