function sum = uskopojasni_sum (n, pn, B, f0, k)
sum=zeros(1,n);
t=linspace(0,1000/f0,n);
A=sqrt(2*pn*B/k);
for i=0:k
  fi=f0-B/2+i*(B/k);
  x=A*sin(2*pi*(fi*t+rand()));
  sum=sum+x;
endfor
endfunction