Keywords: wfdb_tools

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# Preface

The Waveform Database interface library (the WFDB library) is a package of C-callable functions that provide clean and uniform access to digitized, annotated signals stored in a variety of formats. These functions, although originally designed for use with databases of electrocardiograms, are useful for dealing with any similar collection of digitized signals, which may or may not be annotated. The WFDB library has evolved to support the development of numerous databases that include signals such as blood pressure, respiration, oxygen saturation, EEG, as well as ECGs. Thus the WFDB library is considerably more than an ECG database interface.

This guide documents WFDB_tools, a set of MATLAB functions that enables the MATLAB user to take full advantage of the WFDB library and explore or create databases containing a wide variety of signals.

The WFDB_tools functions are not self-contained; rather, they are `wrappers' for the WFDB library functions (i.e. the WFDB library must be installed for the MATLAB functions to work). The wrappers work much in the same way as the WFDB library functions, and the effort is to keep them as true to their counterparts as possible. The usual way to work in MATLAB is to get all results from one function, and therefore the wrappers may seem `low-level' in comparison. Combining just a few of the wrappers in an m-file, however, would produce the `high-level' way of working in MATLAB while keeping the full control of data handling that can only be obtained from the `low-level' C-like wrappers.

This guide includes several short tutorial examples that illustrate how to read and write signals and annotations using these wrappers. It also contains descriptions of all the wrapper functions available to the MATLAB user. Note that MATLAB help files for all of the wrappers are included in the WFDB_tools package, so it is always possible within MATLAB to use a command such as

        help WFDB_sampfreq

to obtain information about how to use any of these wrappers.

The set of wrappers is nearly complete. WFDB library functions for which no wrappers currently exist are wfdbinit, ungetann, sample, sample_valid, setannstr, setanndesc, setecgstr, calopen, getcal, putcal, newcal, flushcal, setmsheader, setwfdb, setibsize, and setobsize.

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