function out = movingAverage(in, fs, fn)
% moving averaging of input signal using recursive moving average
% (c) Jakub Kuzilek, Lenka Lhotska
% http://bio.felk.cvut.cz/~kuziljak/ E-mail: jakub.kuzilek@gmail.com
% Version: 1.0 Last update: 07/01/2013.
% (Version: 1.0, 07/01/2013)
%
%======================================================
%
% PURPOSE: This function filters data using recursive moving average
% filter.
%
% MANDATORY INPUT ARGUMENTS
% in ..... input data MxN, M - length of data, N - number of leads
% fs ..... sampling frequency in Hz
% mode ... 0 - Christov, 1 - Christov + ICA
% OPTIONAL INPUT ARGUMENTS
% none
% OUTPUT ARGUMENTS
% out .... filtered signal
%=========================================================
%
% Related Bibliography:
%
% [1] Kuzilek J, Lhotska L. Electrocardiogram beat detection
% enhancement using independent component analysis. Medical
% Engineering and Physics. 2012.
%
%=========================================================
N = round(fs/fn); % length of filter = filter order
gdel = grpdelay([1 zeros(1,N-1) -1],[N -N]);
gdel = ceil(gdel(find(gdel ~= Inf,1,'first')));
in = [in; zeros(gdel,size(in,2))];
out = filter([1 zeros(1,N-1) -1],[N -N],in); % filtering
out = out(gdel+1:end,:);