[cyxsky]

hz=[20:10:100 200:100:1000 2000:1000:10000];
sp1=[76 66 59 54 49 46 43 40 38 22 14 9 6 3.5 2 1.4 0.7 0 -1 -3 -8 -7 -2 2 7 9 11];
hzi=linspace(2e3,5e3);
spli=interp1(hz,sp1,hzi,'spline');
j=find(hz>=2e3 & hz<=5e3);
semilogx(hz(j),sp1(j),'---',hzi,sp1i)
xlabel('hz'), ylabel('DB')



Error in ==> Untitled78 at 6
semilogx(hz(j),sp1(j),'---',hzi,sp1i)