function [out]=noise_nb(fc,B,N0,t)
%output the narrow band gaussian noise sample with single-sided power
%spectrum N0
%at carrier frequency equals fc and bandwidth equals B
dt=t(2)-t(1);
Fmx=1/dt;

n_len=length(t);
p=N0*Fmx;
rn=sqrt(p)*randn(1,n_len);
[f,rf]=T2F(t,rn);

[t,out]=bpf(f,rf,fc-B/2,fc+B/2)