function rms = mn_rms(freq, asd)
rms = zeros(size(freq));
size(freq)
size(asd)
n = length(freq)
rms(n) = asd(n);
for ii = 2:n
    rms(n-(ii-1)) = sqrt(trapz(freq(n-(ii-1):end),(asd(n-(ii-1):end)).^2));
end