function [Amp, Phase] = peak(Data,a,b,pre)
% finds maximum peak (not maximum point) within the specified range a:b
Amp = zeros(length(Data(1,:)),1);
Phase = Amp;
for i = 1:length(Data(1,:));
    c = a+pre;
    d = b+pre;
    [A,I] = max(Data(c:d,i));
    while (((I == 1) || (I == d-c+1)) && (c ~= d))
        if I == 1;
            c = c+1;
        elseif I == d-c+1
            d = d-1;
        end
        [A,I] = max(Data(c:d,i));
    end
    if c == d; 
        Amp(i,1) = 0;
        Phase(i,1) = 0;
    else Amp(i,1) = A;
        Phase(i,1) = I+c-(pre+1);
    end
end
end