Example 4.1


Question 4.2
Question 4.3

 

Sources of noise – thermal noise

The average power attributable to thermal noise is:

Thermal noise Nav = kTB

where k is Boltzmann's constant = 1.38 x 10–23 watts/Hz/oK, T is the absolute temperature in oK, and B is the bandwidth in which the measurement is made.

Thermal noise can clearly be reduced by cooling the noise source and this very principle is being applied in some radio receivers using cryogenic coolers, to improve the receiver sensitivity.