Modern biomedical signal processing requires the handling of large quantities of data. In the neurological clinic, for example, routine examinations of electroencephalograms are usually performed with eight or more channels, each lasting several tens of seconds. In more elaborate examinations for sleep disorders analysis, hours-long records may be taken. Several hours of electrocardiographic recordings are sometimes required from patients recovering from heart surgery. Various screening programs are faced with the problem of handling a large number of short-term ECG and other signals.