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reference:ft_spikedownsample [2018/08/23 14:43] (current)
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 +=====  FT_SPIKEDOWNSAMPLE =====
 +
 +Note that this reference documentation is identical to the help that is displayed in MATLAB when you type "help ft_spikedownsample"​.
 +
 +<​html><​pre>​
 +  <a href=/​reference/​ft_spikedownsample><​font color=green>​FT_SPIKEDOWNSAMPLE</​font></​a>​ takes electrophysiological data that was continuoudly
 +  sampled at 32KHz and preprocesses and downsamples it to obtain the LFP
 +  data, which can subsequently be processed in more detail.
 + 
 +  Use as
 +    [cfg] = ft_spikedownsample(cfg)
 + 
 +  The configuration should contain
 +    cfg.dataset ​            = string with the input dataset
 +    cfg.output ​             = string with the output dataset (default is determined automatic)
 +    cfg.dataformat ​         = string with the output dataset format, see WRITE_DATA
 +    cfg.channel ​            = Nx1 cell-array with selection of channels (default = '​all'​),​
 +                              see <a href=/​reference/​ft_channelselection><​font color=green>​FT_CHANNELSELECTION</​font></​a>​ for details
 +    cfg.fsample ​            = desired sampling frequency in Hz (default = 1000)
 +    cfg.method ​             = resampling method, can be '​resample',​ '​decimate'​ or '​downsample'​
 +    cfg.timestampdefinition = '​orig'​ or '​sample'​
 +    cfg.channelprefix ​      = string, will be added to channel name, e.g. '​lfp'​ -&gt; '​lfp_ncs001'​ (default = [])
 +    cfg.calibration ​        = optional scaling factor to apply to the data to convert it in uV, see below
 + 
 +  The Neuralynx acquisition system at the FCDC in Nijmegen makes use of
 +  Plexon headstages which have a amplification of 20x. The data that is
 +  written by the Neuralynx acquisition software therefore is 20x larger
 +  than the true microvolt values. When operating <a href=/​reference/​ft_spikedownsample><​font color=green>​FT_SPIKEDOWNSAMPLE</​font></​a>​ on the
 +  *.ncs files that are recorded with the Neuralynx Cheetah software, the
 +  calibration should be set to 1/20. The raw dma file (*.nrd) and the
 +  splitted DMA files contains AD values that are not scaled in uV and
 +  require an additional factor of 64x. If you operate <a href=/​reference/​ft_spikedownsample><​font color=green>​FT_SPIKEDOWNSAMPLE</​font></​a> ​ on
 +  raw dma files or on splitted DMA files, the calibration should be set to
 +  1/(64*20).
 + 
 +  The default is to process the full dataset. You can select a latency range with
 +    cfg.latency ​         = [begin end], default is [0 inf]
 +  or you can specify multiple latency segments with
 +    cfg.latency ​         = [b1 e1; b2 e2; ...]
 + 
 +  Furthermore,​ the configuration can contain the following preprocessing options
 +    cfg.preproc.lpfilter ​     = '​no'​ or '​yes' ​ lowpass filter
 +    cfg.preproc.hpfilter ​     = '​no'​ or '​yes' ​ highpass filter
 +    cfg.preproc.bpfilter ​     = '​no'​ or '​yes' ​ bandpass filter
 +    cfg.preproc.lnfilter ​     = '​no'​ or '​yes' ​ line noise removal using notch filter
 +    cfg.preproc.dftfilter ​    = '​no'​ or '​yes' ​ line noise removal using discrete fourier transform
 +    cfg.preproc.medianfilter ​ = '​no'​ or '​yes' ​ jump preserving median filter
 +    cfg.preproc.lpfreq ​       = lowpass ​ frequency in Hz
 +    cfg.preproc.hpfreq ​       = highpass frequency in Hz
 +    cfg.preproc.bpfreq ​       = bandpass frequency range, specified as [low high] in Hz
 +    cfg.preproc.lnfreq ​       = line noise frequency in Hz, default 50Hz
 +    cfg.preproc.lpfiltord ​    = lowpass ​ filter order
 +    cfg.preproc.hpfiltord ​    = highpass filter order
 +    cfg.preproc.bpfiltord ​    = bandpass filter order
 +    cfg.preproc.lnfiltord ​    = line noise notch filter order
 +    cfg.preproc.medianfiltord = length of median filter
 +    cfg.preproc.lpfilttype ​   = digital filter type, '​but'​ (default) or '​fir'​
 +    cfg.preproc.hpfilttype ​   = digital filter type, '​but'​ (default) or '​fir'​
 +    cfg.preproc.bpfilttype ​   = digital filter type, '​but'​ (default) or '​fir'​
 +    cfg.preproc.lpfiltdir ​    = filter direction, '​twopass'​ (default) or '​onepass'​
 +    cfg.preproc.hpfiltdir ​    = filter direction, '​twopass'​ (default) or '​onepass'​
 +    cfg.preproc.bpfiltdir ​    = filter direction, '​twopass'​ (default) or '​onepass'​
 +    cfg.preproc.detrend ​      = '​no'​ or '​yes'​
 +    cfg.preproc.demean ​       = '​no'​ or '​yes'​
 +    cfg.preproc.baselinewindow = [begin end] in seconds, the default is the complete trial
 +    cfg.preproc.hilbert ​      = '​no'​ or '​yes'​
 +    cfg.preproc.rectify ​      = '​no'​ or '​yes'​
 +</​pre></​html>​