file: nstdb.doc     G. Moody    August 1992

Copyright (C) Massachusetts Institute of Technology 1992.  All rights reserved.

This directory contains the second edition of the MIT-BIH Noise Stress Test

Database.  The directory includes noise records (`bw', `em', and `ma') that may

be added to ECG records by `nst' to create noise stress test records.  It also

contains 12 sample noise stress test records generated by `nst', by adding `em'

noise to MIT-BIH Arrhythmia Database records 118 and 119.  File `nstdbgen' is

the UNIX shell script that was used to generate the sample records.  For

convenience, reference annotation files are included here; all are copies of

the original reference annotation files for records 118 and 119.  The

signal-to-noise ratios (SNRs) during the noisy segments of these records are:

    Record  SNR (dB)    Record  SNR (dB)

    118e24  24      119e24  24 

    118e18  18      119e18  18

    118e12  12      119e12  12

    118e06   6      119e06   6

    118e00   0      119e00   0

    118e_6  -6      119e_6  -6

The records with SNRs of 0 and -6 dB are written in format 16, since the sample

values occasionally exceed the 12-bit range enforced by format 212 (used for

the other records in this directory).

The directory `old' contains the first edition of the MIT-BIH Noise Stress Test

Database, reproduced here for the sake of completeness.  Unless you wish to

repeat an experiment based on the first edition, use the records in this

directory.

For further information about:      see:

 these records              `../readme.doc'

 signal-to-noise ratio,         the ECG Database Applications Guide,

  and `nst'               or `../src/db/doc/nst.1'

 testing noise tolerance of     the ECG Database Applications Guide

  arrhythmia detectors           or `../src/db/doc/eval.tex'

 signal file formats            the ECG Database Applications Guide

                      or `../src/db/doc/signal.5'

 the first edition of           `old/oldnstdb.doc'

  this database