School homework help [Communication systems, Taub]

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gcmarimon

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Hi all,
I need help with the resolution of the exercise 14.10-1 from Taub and schilling Principles of Communication systems book.
The answer for the question is as follows, but i need the full resolution, if anyone can help.
Q:
A) Explain why F cannot be less than 1. (where F is the noise figure of the two-port)
B)Verify Eqs. (14-10-2) and (14.10-3)

Eq: 14-10-2
T_e = T_0 (F-1)

Eq: 14.10-3
F= 1+ (T_e/T_0) = (T_e+T_0)/T_0

R:
A) The actual output noise cannot be les than the amplified source noise.

B) F(f)=G_a0/(g_a (f)(K T_0/2))=((g_a (f)K(T_0+T_e ))/2)/((g_a (f)KT_0)/2)=(T_0+T_e)/T_0 =1+T_e/T_0 ∴T_e=T_0 (F-1)

Im not sure if i can post any links here... i have the chapter 14 and i can share the exercises if needed. I need these resolution in two days =[
plz help.
Best regards
 

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