FT_DATATYPE_FREQ describes the FieldTrip MATLAB structure for freq data

 The freq data structure represents frequency or time-frequency decomposed
 channel-level data. This data structure is usually generated with the
 FT_FREQANALYSIS function.

 An example of a freq data structure containing the powerspectrum for 306 channels
 and 120 frequencies is

       dimord: 'chan_freq'          defines how the numeric data should be interpreted
    powspctrm: [306x120 double]     the power spectum
        label: {306x1 cell}         the channel labels
         freq: [1x120 double]       the frequencies expressed in Hz
          cfg: [1x1 struct]         the configuration used by the function that generated this data structure

 An example of a freq data structure containing the time-frequency resolved
 spectral estimates of power (i.e. TFR) for 306 channels, 120 frequencies
 and 60 timepoints is

       dimord: 'chan_freq_time'     defines how the numeric data should be interpreted
    powspctrm: [306x120x60 double]  the power spectum
        label: {306x1 cell}         the channel labels
         freq: [1x120 double]       the frequencies, expressed in Hz
         time: [1x60 double]        the time, expressed in seconds
          cfg: [1x1 struct]         the configuration used by the function that generated this data structure

 Required fields:
   - label, dimord, freq

 Optional fields:
   - powspctrm, fouriesspctrm, csdspctrm, cohspctrm, time, labelcmb, grad, elec, cumsumcnt, cumtapcnt, trialinfo

 Deprecated fields:
   - <none>

 Obsoleted fields:
   - <none>

 Revision history:

 (2011/latest) The description of the sensors has changed, see FT_DATATYPE_SENS
 for further information.

 (2008) The presence of labelcmb in case of crsspctrm became optional,
 from now on the crsspctrm can also be represented as Nchan * Nchan.

 (2006) The fourierspctrm field was added as alternative to powspctrm and
 crsspctrm. The fields foi and toi were renamed to freq and time.

 (2003v2) The fields sgn and sgncmb were renamed into label and labelcmb.

 (2003v1) The initial version was defined.

 See also FT_DATATYPE, FT_DATATYPE_COMP, FT_DATATYPE_DIP, FT_DATATYPE_FREQ,
 FT_DATATYPE_MVAR, FT_DATATYPE_RAW, FT_DATATYPE_SOURCE, FT_DATATYPE_SPIKE,
 FT_DATATYPE_TIMELOCK, FT_DATATYPE_VOLUME