# Import external data: General information

External data files

To import external data you need to link it to an acquired Trial, an Arena or a Subject.

You can import external data with the following characteristics:

▪It is stored in ASCII format.

▪The sample rate is constant, or when it is not constant, the data file contains time stamps.

▪The file contains at least 15 data lines. It preferably contains a header with information describing the data sets. This information about the data set, such as data set name, date and time information, sample rate, is typically stored in the header section of a DAQ export file

▪You can import European Data Format (EDF) or BioSemi Data Format (BDF) data files. Import of EDF+ or BDF+ files is not supported.

Notes

▪It is not necessary that external data are recorded when you do the tracking; for example, when you track from video files. However, you must ensure synchronization between the external data and the video file.

▪You can only import external data into an acquired Trial. This is indicated in the Trial List by ‘Acquired’ in the System Variable Status column.

Data sets within a file

An external data file can contain one or more data sets. For example, you test three rats, each in its own arena, and for each rat you have acquired ECG data. The resulting external data file contains three ECG data sets. In EthoVision XT you now have the option:

▪to link the complete external data file (i.e. all three data sets at once) to a Trial, Arena, or Subject.

▪to link one or more data sets from an external data file to a Trial, Arena, or Subject.