Difference between revisions of "ASCII File Format"
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If an epoch of a continuous EEG is exported in ASCII multiplexed format, the first header line contains the additional item 'Time', which indicates the daytime of the first sample in the exported segment. | If an epoch of a continuous EEG is exported in ASCII multiplexed format, the first header line contains the additional item 'Time', which indicates the daytime of the first sample in the exported segment. | ||
The second line of the header contains labels for each channel, which may be either the original channel names, or the names of the channels of the current montage. | The second line of the header contains labels for each channel, which may be either the original channel names, or the names of the channels of the current montage. | ||
| − | Each subsequent line contains values for all 'Channels' at one time point, in floating point or scientific format. Values are given for the current or the original montage, selected as described | + | Each subsequent line contains values for all 'Channels' at one time point, in floating point or scientific format. Values are given for the current or the original montage, selected as described in [[Export]]. |
| − | Labels for source montages | + | Labels for standard source montages follow a nomenclature as described in [[BESA_Research_Montage_Editor#Naming_Scheme_of_Standard_Sources|Montage Editor: Naming Scheme of Standard Sources]]. |
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''' Example ''' | ''' Example ''' | ||
Latest revision as of 13:48, 4 May 2021
| Module information | |
| Modules | BESA Research Basic or higher |
| Version | 5.2 or higher |
BESA Research can read 2 types of ASCII file formats to import data. These are identified by different extensions:
- ASCII vectorized file format (*.avr)
- ASCII Multiplexed file format (*.mul)
ASCII Vectorized file format
The ASCII vectorized file format stores data of one channel (all time points) per line. It is defined as follows:
The first of two header lines contains the following data descriptors:
| Npts | number of sampled points in each channel |
| TSB | time sweep begin [ms]. Time of first data point relative to zero of epoch |
| DI | digitization or sampling interval [ms] |
| SB | scaling bins/microvolt in file = number corresponding to 1 microvolt |
| SC | scaling calibration, used for setting magnitude of display in BESA Research |
| Nchan | number of channels |
| SegmentName | an optional label describing the data |
The second line of the header contains a label for each channel. Each of the subsequent Nchan lines of the file contains values for all Npts time points in floating point or scientific format.
Example
Npts= 256 TSB= 0.000 DI= 4.000000 SB= 1.000 SC= 200.0 Nchan= 27 SegmentName= Segment1 O1 Oz P3 T5 T3 C3 F7 F3 Fp1 Fz Cz Pz Fp2 F4 F8 C4 T4 T6 P4 Fpz O2 M2 M1 F10 F9 T10 T9
ASCII Multiplexed file format
The ASCII multiplexed file format stores data of one time point (all channels) per line. It is defined as follows:
The first of two header lines contains similar information to that of the ASCII vectorized file:
- TimePoints
- Channels
- BeginSweep[ms]
- SamplingInterval[ms]
- Bins/uV
- SegmentName
Note that the item 'SegmentName' is missing if no segment comment is specified when writing a segment to file. If an epoch of a continuous EEG is exported in ASCII multiplexed format, the first header line contains the additional item 'Time', which indicates the daytime of the first sample in the exported segment. The second line of the header contains labels for each channel, which may be either the original channel names, or the names of the channels of the current montage. Each subsequent line contains values for all 'Channels' at one time point, in floating point or scientific format. Values are given for the current or the original montage, selected as described in Export.
Labels for standard source montages follow a nomenclature as described in Montage Editor: Naming Scheme of Standard Sources.
Example
TimePoints= 512 Channels= 27 BeginSweep[ms]= 0.00 SamplingInterval[ms]= 5.000 Bins/uV= 1.000 Time=22:02:53 SegmentName=Segment1 O1 Oz P3 T5 T3 C3 F7 F3 Fp1 Fz Cz Pz Fp2 F4 F8 C4 T4 T6 P4 Fpz O2 M2 M1 F10 F9 T10 T9
