hi everry one , this program is filter ? if it is filter what is the type of filter ? (YOU CAN ADD SOME COMMENT )

 global nfile A flag
                [fil pth]=uigetfile('.dat','Enter File Name Wich You Want to Work')
                file=[pth fil];
                fid=fopen(file,'r');
                nfile=fread(fid);
                nfile=imresize(nfile,[183 1]);% it is for compression? 
                axes(handles.axes1)
                plot(nfile,'-'), title('Original Signal')

                figure(1),plot(nfile,'-'), title('Original Signal')

                z=zeros(100,1);
                A=[z;nfile;z]; %it is filter?
                axes(handles.axes2)
                plot(A,'-'),title('Original Signal With Pad')

                figure(2),plot(A,'-'),title('Original Signal With Pad')
                flag=2;

Answer 1

[Image Analyst]

It's not a filter. It simple resizes the signal to be exactly 183 elements long and slaps 100 zeros on either end of it. I don't know why they wanted/needed to do that. The only way you could say it was a filter was if the signal was longer than 183 elements and you squeezed it down - that's like a low pass filter but I don't think their intent was so much low pass filtering as it was resizing.

[serhat dag]

it is for ecg signal.When ı have applied,these codes behavior like low pass and HıGH PASS filter . But I could not be sure

[Image Analyst]

There is no way it's a high pass filter.

Even if the signal was less than 183 elements and you expanded it to be 183 elements, you'd have more elements but that does not make it a high pass filter. It would be essentially no filter at all, you're just interpolating in more elements. All the frequencies there originally are still there.

If you shrink the signal, then nfile could be thought of as a low pass filter, but again, definitely not a high pass filter.

A is really nothing but your resized signal with zeros on either side of it, so it should not really be called a filtered version of nfile.

Again, I don't think low pass filter is really the intent of this code. It's just about resizing, not filtering. We can't know why because I think that can only be learned by code after the code you have shown, if there is any.

By the way, here is preferred code to ask the user to browse to a filename:

% Have user browse for a file, from a specified "starting folder."
% For convenience in browsing, set a starting folder from which to browse.
startingFolder = 'C:\Program Files\MATLAB';
if ~exist(startingFolder, 'dir')
  % If that folder doesn't exist, just start in the current folder.
  startingFolder = pwd;
end
% Get the name of the file that the user wants to use.
defaultFileName = fullfile(startingFolder, '*.*');
[baseFileName, folder] = uigetfile(defaultFileName, 'Select a file');
if baseFileName == 0
  % User clicked the Cancel button.
  return;
end
fullFileName = fullfile(folder, baseFileName)

% Now open the file:
fid=fopen(fullFileName,'r');

[Guillaume]

I guess it could be considered a very crude low-pass filter, but using imresize for that is totally inappropriate and confusing. The default interpolation method is bicubic but since the input and output are just one column, it's simply a cubic interpolation of a vector. Hence,

nfile = interp1(nfile, (1:183).', 'cubic'); %or 'pchip' in R2016b and later

would be a lot more appropriate.

[serhat dag]

.Thank you for your help. I understood too. It is not filter. In this case the following code is used for filter??(appcoef )

global nfile Qamp_mv Ramp_mv Samp_mv Tamp_mv P_1 Pamp_mv A flag c

                    if flag==2
                        flag=3;

                        [c,l]=wavedec(nfile,8,'db8');

                        ca1=appcoef(c,l,'db8',1);
                        ca2=appcoef(c,l,'db8',2);
                        ca3=appcoef(c,l,'db8',3);
                        ca4=appcoef(c,l,'db8',4);
                           figure(2),plot(ca1,'-k'),title('Cofficients of Signal At l Level Decomposition')
                            figure(3),plot(ca2,'-k'),title('Cofficients of Signal At 2 Level Decomposition')
                             figure(4),plot(ca3,'-k'),title('Cofficients of Signal At 3 Level Decomposition')
                              figure(5),plot(ca4,'-r'),title('Cofficients of Signal At 4 Level Decomposition')
                              flag=3 ;

                    else
                        errordlg('First select ECG Signal')
                    end

[Image Analyst]

I don't know. It says wavedec so it might be some kind of wavelet filter, but I don't have the wavelet toolbox so I can't really say what this code does. Can't you ask the author?

[serhat dag]

i can Not (I do not know who wrote it). Thank you for everything

[serhat dag]

do u have solution of this book https://www.amazon.com/Medical-Imaging-Signals-Systems-2nd/dp/0132145189

[serhat dag]

Do you have slution of Medical Imaging Signals and Systems-(Jerry L. Prince Jonathan M. Links)

[Walter Roberson]

No, we do not have the solutions for that book.