%%figure 8 the distribution of apparent frequency  of one station 
%  load('300km_350km_400km_500km.mat')

[h1,c1]=hist(af300(dr300>300 &dr300<310),9e3:0.2e3:18e3);
[h2,c2]=hist(af350(dr350>350 &dr350<360),9e3:0.2e3:18e3);
[h3,c3]=hist(af400(dr400>400 &dr400<410),9e3:0.2e3:18e3);
% [h3,c3]=hist(af500(dr500>500 &dr500<510),9e3:0.2e3:16e3);

figure
plot(c1/1000,h1/size(af300(dr300>300 &dr300<310),2),'b','linewidth',2)
hold on
plot(c2/1000,h2/size(af350(dr350>350 &dr350<360),2),'k','linewidth',2)
plot(c3/1000,h3/size(af400(dr400>400 &dr400<410),2),'r','linewidth',2)
% plot(c3/1000,h3/size(af500(dr500>500 &dr500<510),2),'r','linewidth',2)
xlabel('[fi] = kHz','FontSize', 20);
ylabel('[f(x)*dx]','FontSize', 20);
set(gca,'fontsize',16)
xlim([9 16])
legend('300km','350km','400km')
grid on
% print fig8.tif -dtiff