%%
a = ao(plist('waveform', 'noise', 'nsecs', 1e6, 'sigma', 25, 'yunits', 'm'));

Navs = [2:10 20:20:100 200:200:1000 5000 10000];

for jj=1:length(Navs)
  S = a.psd(plist('navs',Navs(jj),'win','BH92'));
  rat(jj) = mean((S.dy)./S.y);
  N(jj) = S.data.navs;
end

figure
loglog(Navs, rat, 'b+');
hold on
grid on
loglog(Navs, 1./sqrt(N),'k');
xlabel('N');
ylabel('(S.dy)./S.y');
legend('','1/sqrt(N)')