edfwrite replaces all values in sigdata matrix with "0.48829" in every cell (matlab 2021b)

Hi Matlab team,

I tried the following code in matlab 2021b and it produced a matrix with every cell containing only one value (for the most part): 0.48829.

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fs = 256;

hdr = edfheader("EDF");

hdr.StartDate = '12.01.17';

hdr.StartTime = '01.45.04';

hdr.PhysicalDimensions = repmat("mV",1,38);

hdr.Patient = '...';

hdr.SignalLabels = ["C001";"C002";"C003";"C004";"C005";"C006";"C007";"C008";"C009";"C010";"C011";"C012";"C013";"C014";"C015";"C016";"C017";"C018";"C019";"C020";"C021";"C022";"C023";"C024";"C025";"C026";"C027";"C028";"C029";"C030";"C031";"C032";"C033";"C034";"C035";"C036";"C037";"C038"]';

hdr.NumDataRecords = 1;

hdr.Recording = ['SampleRate 256' 'Recording.PatientID_StudyID = 0 0' '...'];

hdr.PhysicalMin = repmat(-32000,1,38);

hdr.PhysicalMax = repmat(32000,1,38);

hdr.DigitalMin = repmat(-32768,1,38);

hdr.DigitalMax = repmat(32767,1,38);

hdr.NumSignals = 38;

hdr.DataRecordDuration = seconds(length(sigdata2)/fs);

edfw = edfwrite('Exportv2_3.edf',hdr,sigdata2);

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The 'sigdata2' matrix is a 5122 X 38 DOUBLE matrix. (38 channels)

Thanks in advance for any guidance.

J.

[Max Heimann]

What is your question?

[Joanne Hall]

Thanks Max. My question is how to get the edfwrite function to write out my original EEG data matrix with the original data values in the 'sigdata' (input argument) WITHOUT instead overwriting the original numeric values in the datamatrix by replacing all of those values with one single number: which is 0.488289. This one value is listed in every cell of the data matrix, and results in flat EEG signals when I open the edf file in edfbrowser. Please help.

I have attached the resulting data file as a .txt.

[Joanne Hall]

Hi Max,

I am also attaching the original data matrix that I would like to have as the edf output (instead of all cells containing the same value).

Joanne