Building Earth Observation Cameras

136 Building Earth Observation Cameras

with a bandwidth Δf, the mean square thermal noise current (

i

th

2

) is given as

follows:

i

kT f

R

=

4

th

2

(5.15)

where k is Boltzmann's constant (joules per kelvin), T is the resistor's tem-

perature (kelvin), and R is the effective load resistance. A higher value of R

reduces the thermal noise but increases the time constant, thereby reducing

the bandwidth, and hence requires a judicious choice of the load resistor.

Generation–recombination (G-R) noise is caused by uctuations in the elec-

tron–hole generation rate and recombination rate. G-R noise is unique to

photoconductive detectors.

1/f noise: The mechanisms t ...