Reading signals

Assuming that the WFDB Software Package has been installed correctly, the record ``100s'' should be available. Reading the first ten samples of this record using MATLAB would be done as:

    >> S = WFDB_isigopen('100s')
    S = 
    2x1 struct array with fields:
        fname
        desc
        units
        gain
        initval
        group
        fmt
        spf
        bsize
        adcres
        adczero
        baseline
        nsamp
        cksum
    >> DATA = WFDB_getvec(length(S), 10)
    DATA =
             995        1011
             995        1011
             995        1011
             995        1011
             995        1011
             995        1011
             995        1011
             995        1011
            1000        1008
             997        1008

The first command, S = WFDB_isigopen('100s'), reads the header file of record 100s and returns the information in a structure (S, in this case). The length of S equals the number of signals in the data file. The fields of S contain the signal settings. To access, for example, the gain of signal 0 and the description of signal 1, use the commands:

    >> S(1).gain
    ans =
       200
    >> S(2).desc
    ans =
    V5

(Remember: the first signal is signal 0, not signal 1! Its attributes are found in the first structure, S(1). This will matter in later examples.)

The second command, DATA = WFDB_getvec(length(S), 10), reads data from the previously opened record. The two input parameters are the number of signals (found as length(S)) and the desired number of samples (if omitted, the whole record is read).

Finally, don't forget

    >> WFDB_wfdbquit

to close all open files.

An elaborated version of this example is provided in the examples directory of the WFDB_tools package (look for example1.m).