11/24/2002
Noise: An Introduction
19
Thermal Noise
•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