•From
 the Brownian motion of electrons in a resistive material.
 • pn(f) = kT is the power spectrum where:
 •k
 = 1.3805 * 10-23 (Boltzmann’s constant) and
 •T
 is the absolute temperature (°Kelvin)
 •This
 is a “white” noise (“flat” spectrum)
 –From a
 color analogy
 –White
 light has all colors at equal energy
 •The
 probability distribution is Gaussian