function [worst_scalloping_loss_dB, avg_scalloping_loss_dB, SNR_loss_dB] = cal_winloss(win)
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%
% Calculating losses of windowing
% Start : 23.08.25
% End   : 23.08.25
% developed by Kwanggoo Yeo
% 
% Description
%   - Input
%       - 1) win [vector] : window function
%
%   - Output
%       - 1) worst_scalloping_loss_dB [scalar], [dB] : scalloping loss in worst case 
%       - 2) avg_scalloping_loss_dB [scalar], [dB]   : scallopoing loss in average case [uniform distribution]
%       - 3) SNR_loss_dB [scalar], [dB]              : SNR processing gain loss 
%
%
% History
% (23.08.25) Completed
%
% Referece
%   - 1) Mark A. Richards, "Fundamentals of Radar Signal Processing 1st edition", p.257
%
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if size(win, 1) > 1
    win = win.';
end

N = length(win);

worst_scalloping_loss_dB = mag2db( abs( sum( win .* exp(-1i * pi / N * [0:N-1]))) / sum(win));

SNR_loss_dB = pow2db( sum(win)^2 / (N * sum(win.^2)) );

findex = linspace(-pi/N, pi/N, 10000);

for idx = 1 : length(findex)
    val(idx) = (abs( sum( win .* exp(-1i * findex(idx) * [0:N-1]))) / sum(win));
end
avg_scalloping_loss_dB = mag2db(sum(val)/10000);

end