edfwrite distortes my signal!

Hi there,

I would like to open an EDF file, modify the signal and export it again in EDF; however, the edfwrite distortes my signal!

original signal:

exported signal:

clc;

clear all

close all

[EEG_for_HFO, annotations]=edfread('Rec-06.0001-GFP.edf');

header=edfinfo('Rec-06.0001-GFP.edf');

%% Inputs

EEG=EEG_for_HFO.EEG;

EEG=cell2mat(EEG);

SR=1000; % Sampling rate

% % Artifact Removal

% Threshold=1.5; % Threshold level for Artifact Removing in mili volt

% Window=10; % Length of step for Artifact Removing in mili second

% TimeDuration=100; % Time duration for Artifact Removing in mili second - Before and After

% % Highpass Filter

% FilterLevel=5; % Level of highpass filter

% Cutoff=2;

% %% Orders ------> 1 means On

% ArtifactRemoving=1;

% Filter=1;

% %% Plot

% figure;

% Time=1:length(EEG);

% plot(Time,EEG,'b');

% title('Raw signal')

% xlabel('Time(ms)');ylabel('EEG(mV)')

% %% Artifact Removal

% if (ArtifactRemoving==1)

% Start=100;

% End=Start+Window;

% for ii=1:(round(length(EEG)/Window)-Window)-1

% [Max(ii),max_indices(ii)]=max(abs(EEG(Start:End)));

% if Max(ii)>Threshold

% Before=max_indices(ii)-TimeDuration+Start;

% After=max_indices(ii)+TimeDuration-1+Start;

% EEG(Before:After)=0;

% end

%

% Start=Start+Window;

% End=End+Window;

% end

%

% hold on

% Time=1:length(EEG);

% plot(Time,EEG,'r')

% end

%

% %% Highpass Filter

% if (Filter==1)

%

% a=[];b=[];

% [b,a]=butter(FilterLevel,Cutoff/(SR/2),'high'); % Highpass filtering 2 Hz

% EEG=filtfilt(b,a,EEG);

% end

%% creating header

hdr=edfheader("EDF+");

hdr.Patient="Mice";

hdr.Recording="2021";

hdr.NumDataRecords=1;

hdr.NumSignals=1;

hdr.SignalLabels="EEG";

hdr.PhysicalDimensions="mV";

hdr.PhysicalMin=-5;

hdr.PhysicalMax=5;

hdr.DigitalMin=-32256;

hdr.DigitalMax=32256;

%% exporting edf

%EEGCell= mat2cell(EEG(:), SR*ones(1,numel(EEG)/SR), 1);

f=edfwrite("file.edf",hdr,EEG, annotations);

You can find an example of my EDF files here: EDF

Thanks!