<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> <!--Converted with LaTeX2HTML 98.1p1 release (March 2nd, 1998) originally by Nikos Drakos (nikos@cbl.leeds.ac.uk), 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> <TITLE>Normalization and Fitting</TITLE> <META NAME="description" CONTENT="Normalization and Fitting"> <META NAME="keywords" CONTENT="vol2"> <META NAME="resource-type" CONTENT="document"> <META NAME="distribution" CONTENT="global"> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> <LINK REL="STYLESHEET" HREF="vol2.css"> <LINK REL="next" HREF="node139.html"> <LINK REL="previous" HREF="node137.html"> <LINK REL="up" HREF="node136.html"> <LINK REL="next" HREF="node139.html"> </HEAD> <BODY > <!--Navigation Panel--> <A NAME="tex2html3161" HREF="node139.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="icons.gif/next_motif.gif"></A> <A NAME="tex2html3158" HREF="node136.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="icons.gif/up_motif.gif"></A> <A NAME="tex2html3152" HREF="node137.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="icons.gif/previous_motif.gif"></A> <A NAME="tex2html3160" HREF="node1.html"> <IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="icons.gif/contents_motif.gif"></A> <BR> <B> Next:</B> <A NAME="tex2html3162" HREF="node139.html">Convolution and Deconvolution</A> <B> Up:</B> <A NAME="tex2html3159" HREF="node136.html">Spectral Analysis</A> <B> Previous:</B> <A NAME="tex2html3153" HREF="node137.html">Rebinning and Interpolation</A> <BR> <BR> <!--End of Navigation Panel--> <H2><A NAME="SECTION001062000000000000000"> Normalization and Fitting</A> </H2> A frequently used procedure, alternative to the correction for the chromatic response, is to normalise the continuum to unity by dividing the observed spectrum by a smooth approximation of its continuum. This approximation can be obtained either interactively with the graphic cursor, or from a table (command <TT>NORMALIZE/SPECTRUM</TT>) or by dividing the raw data by itself after filtering or smoothing. Median filtering and running average algorithms are well suited for this purpose (command <TT>FILTER</TT>). A spline fit can be made to the points defined interactively as well as to the filtered data (command <TT>CONVERT/TABLE</TT>). The MIDAS Fitting Package permits to go further and perform a more advanced modelling of the continuum. <P> <BR><HR> <ADDRESS> <I>Petra Nass</I> <BR><I>1999-06-15</I> </ADDRESS> </BODY> </HTML>
