Exam text content

ELT-45106 RF eguipment for wireless networks
Final examination (Ari Asp)
26.2.2018 (calculator allowed)

You have to answer to all five (5) guestions. Check eguations from next page.
1 Explain the why IP3 causes more problem than IP2.

2. What are main differences between Near field and far field. Explain at least two
different criteria how do you know you are working in far field.

3. Explain following figure. What kind of systems are behind those curves and what
are the main theorethical differences between them?

10 -—-—-

normalized output SNR, dB

 

branches

4. Explain VSWR. When it occurs?

5. A receiver front is following:

ANTENNA LNA MIXER IF FILTER AMPLIFIER

cable — Amplifier =
loss p NF=6dB

      
 

     

cable loss
=5 dB G=22dB
Te=438 K

G=12dB
NF = 6 dB

Calculate the total NF and Te for output.

Draw a figure and note all the calculations.
Hint:

 
Some (more or less) useful & uations:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

G,=,G, < N < 17B
E "R — AR 4R
Po
v PW]
N 1010g,,—
Pi 4 [ull g jhUr-2'00s0) yin [120 W
108, 0 = 108, G, + 108,0 G; + 10810 G. =a1(7) Sar! rm
91% = 10810 Ga + 10810 C6 + 10810 % Anr Anr 1070
P;
000
p. c OP T+T 1
10108,, = 1=< = >1 2h-fa. 2h-N
* p, f P 7,+T, Ji J2- 42 = CNRp
osan < oofu CNRout
A = |[[ 49.— 4 R=0.62.[E/2
vi 4nR divD(r,1)= Plr.t)
0 dBd=2.15 dBi R,=R,+R r- divB(r,f)=0
3 0B(r) ——
1 = 6.546-10*' Isec, Planck's constant 4 curl (rf) = —28(r1)
c= 299 792 458 mvs, speed of light Pa I+ Z,=R,+ JA, ot
- 165? j/01 , Ir" OD(r,f
k= 1338-10 J/*K, Boltsmann's constant Vain 1 | | 010g, |r] dB ourl H (r,f) = a ) 13(r)
F-1 F-1
F,=f 4+3—4..4—— F(SSL
m G 66 GGG SSL = 20 o F(0.9)= 29.6): (0.9)
7. =7,+184 Tä 4 -
G, GG V(z)=We +V el
T. = dP
T =T(F-N)of=1+— — Umax P G=g,D ; P
€ n )o T, D= T. €, = U J
NF=10-l0g(f) "a
1(2)=1(0)sin 9(2-0] Ap=Y ge vo pdoosl0)+a
47U (0,6) 2 =
G(9,9)= P 1 - -
" P =3 "R AF =1,e* +107" 416? ++], je?"
Nu a=k:T-B-Fy:Gr ma NN -
Nin as =6:T-B* Fs 472 400012 Sn(NYP2) MILE]
- : sin(/2) N sin(w/2)

N = Nat p+ Win as = T*B(Pis + Gr va Fo)

plp)=e", 720
Vo

P.(7)=Pr[T<7]

u
= Pr[T,nveTy <7]=][%.07)

P.(7)=Pr[r<7]= Pr[max (T', < 1]

Pr, TattTy SI] (1-07 J