file: README		G. Moody	14 June 1995

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Power spectral density estimation and related applications
Copyright (C) 1999 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, write to the Free Software Foundation, Inc.,
59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

You may contact the author by e-mail (george@mit.edu) 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 (at the same level as this
one), and also require either `plt' (not generally available) or `gnuplot'
(a freely available plotting utility) for output.  The programs to be compiled
within this directory are independent of the DB Software Package, and require
only the standard C math library.  This directory also contains documentation
for these programs and scripts in the form of UNIX man pages.

These programs were written for and tested under SunOS, Solaris, and Linux,
although they should be portable to other operating systems, including MS-DOS.
The shell scripts are UNIX-specific, but should be easy to adapt to MS-DOS.
Note that versions of `gnuplot' are available for both MS-DOS and MS-Windows.

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.dos	`make' description file for compiling these applications using
		 unsupported compilers from Borland, Microsoft, etc.
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

