file: README		G. Moody	14 June 1995
			Last revised:	 8 June 2005

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Power spectral density estimation and related applications
Copyright (C) 1995-2005 George B. Moody

These programs are free software; you can redistribute them and/or modify
them under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2 of the License, or (at your
option) any later version.

These programs are distributed in the hope that they will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
more details.

You should have received a copy of the GNU General Public License along with
these programs; if not, see <http://www.gnu.org/licenses/>.

You may contact the author by e-mail (wfdb@physionet.org) or postal mail
(MIT Room E25-505A, Cambridge, MA 02139 USA).  For updates to this software,
please visit PhysioNet (http://www.physionet.org/).
_______________________________________________________________________________

This directory contains sources for applications for power spectral density
(PSD) estimation, and sample Unix shell scripts for using these applications to
obtain heart rate power spectra based upon beat annotation files.  The scripts
require 'ihr' and 'tach' from the '../app' directory, and also require either
'plt' or 'gnuplot' for output.  (See http://www.physionet.org/physiotools/plt/
or http://www.gnuplot.info/.)  The programs to be compiled within this
directory are independent of the remainder of the WFDB Software Package, and
require only the standard C math library.  The directory '../doc/wag-src'
contains documentation for these programs and scripts in the form of Unix man
pages.

These programs were written for SunOS, Solaris, and GNU/Linux;  they are also
portable to and have been tested with other versions of Unix, as well as
MacOS X and MS-Windows (with the free Cygwin toolkit, http://www.cygwin.com/).

Follow the instructions in `Makefile' to install these applications and their
man pages on your system.

The following files will be found in this directory:

Makefile	`make' description file for compiling these applications using
		 ANSI/ISO standard C compilers on supported platforms
Makefile.top	Used by ../configure to construct Makefile (comments only)
Makefile.tpl	Used by ../configure to construct Makefile (portable section)
README		this file
coherence.c	Calculate coherence and cross-spectrum of two time series
fft.c		Calculate fast Fourier transform (FFT), inverse FFT, etc.
hrfft	        Plot heart rate power spectrum (using tach and fft)
hrlomb		Plot heart rate power spectrum (using ihr and lomb)
hrmem		Plot heart rate power spectrum (using tach and memse)
hrplot		Plot heart rate time series (using ihr)
log10.c		Utility for calculating common logarithms of two data columns
lomb.c		Calculate Lomb periodogram from an irregularly-sampled series
memse.c		Calculate PSD estimate using maximum entropy (all poles)
		 method (also known as autoregressive, or AR, PSD estimation)
plot2d		A script that drives `gnuplot', using a few `plt' options
plot3d		Another `gnuplot' driver, for 3-D plots