Note that this reference documentation is identical to the help that is displayed in MATLAB when you type “help ft_resampledata”.
FT_RESAMPLEDATA performs a resampling or downsampling of the data Use as [data] = ft_resampledata(cfg, data) The data should be organised in a structure as obtained from the FT_PREPROCESSING function. The configuration should contain cfg.resamplefs = frequency at which the data will be resampled (default = 256 Hz) cfg.detrend = 'no' or 'yes', detrend the data prior to resampling (no default specified, see below) cfg.demean = 'no' or 'yes', baseline correct the data prior to resampling (default = 'no') cfg.feedback = 'no', 'text', 'textbar', 'gui' (default = 'text') cfg.trials = 'all' or a selection given as a 1xN vector (default = 'all') cfg.sampleindex = 'no' or 'yes', add a channel with the original sample indices (default = 'no') Instead of specifying cfg.resamplefs, you can also specify a time axis on which you want the data to be resampled. This is usefull for merging data from two acquisition devides, after resampledata you can call FT_APPENDDATA to concatenate the channles from the different acquisition devices. cfg.time = cell-array with one time axis per trial (i.e. from another dataset) cfg.method = interpolation method, see INTERP1 (default = 'pchip') Previously this function used to detrend the data by default. The motivation for this is that the data is filtered prior to resampling to avoid aliassing and detrending prevents occasional edge artifacts of the filters. Detrending is fine for removing slow drifts in data priot to frequency analysis, but detrending is not good if you subsequenlty want to look at the evoked fields. Therefore the old default value 'yes' has been removed. You now explicitely have to specify whether you want to detrend (probably so if you want to keep your analysis compatible with previous analyses that you did), or if you do not want to detrent (recommended in most cases). If you observe edge artifacts after detrending, it is recommended to apply a baseline correction to the data. The following fields in the structure 'data' are modified by this function data.fsample data.trial data.time To facilitate data-handling and distributed computing you can use cfg.inputfile = ... cfg.outputfile = ... If you specify one of these (or both) the input data will be read from a *.mat file on disk and/or the output data will be written to a *.mat file. These mat files should contain only a single variable, corresponding with the input/output structure. See also FT_PREPROCESSING