function y = sdf2(x, range, windowsize)
% y=sdf2(x, range, windowsize) - running average squared difference function
% range and windowsize are in samples
% fixed window is at end of input array, moving window slides back

N = size(x,2);
if (range+windowsize>= N)
	error('range+windowsize larger than input array');
end;
y = zeros(size(x,1) ,range);


z = x(:, N-windowsize+1:N);
for i = 0:range-1
	zz = x(:, N-windowsize+1-i: N-i);
	zzz = sum( (z' - zz').^2);
	y(:,i+1) = zzz';
end