Let N(t) denote white Gaussian noise. Its power spectral density has the form
1
\(\frac{1}{{\sqrt {2\pi {\sigma ^2}} }}e\frac{{{{\left( {x - \mu } \right)}^2}}}{{2{\sigma ^2}}}\)
2
\(\frac{{{N_o}}}{2}\delta \left( \tau \right)\)
3
\(\frac{{\sin \left( {\pi \tau } \right)}}{{\pi \tau }}\)
4
\(\frac{{{N_o}}}{2}\) for -∞ < ω < ∞