Electronic Engineer's Notebook

Communications


Noise

Propagation


Noise

RMS thermal noise =

Available thermal noise power = kTB

Noise factor (T = 290K)

Noise figure = 10log(F)

Friis's formula

Friis's formula

Equivalent input noise temperature T e = (F - 1)T o

Quantization noise power = (lsb) 2 /12

Ideal N bit A/D
Ideal A/D SNR
for a full scale sine wave signal

Practical A/D
SNR = -10log((2 pt F) 2 + ((1+e)/2 N ) 2 + (n/2 N ) 2 )
t = rms aperture uncertainty
F = IF frequency
e = average DNL of converter in lsb
n = rms noise level of the converter in lsb

Propagation in Free Space

Received power Free space propagation

Power gain G = 4 p A eff / l 2

Radar range equation:
Radar range equation
s is the target RCS, t is the pulse width, L represents system losses, T S is the system noise temperature


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Last updated 16 July, 2000

© 2000 Michael Wells