ECE - Questions and solutions set-6

Electronics and communication Engineering Questions and solutions set-6
Question:-
Option (A)
2 inputs ANDs only
Option (B)
2 input XOFS and 4 input AND gates only
Option (C)
Two 2 input NORs and one XNOR gate
Option (D)
XOR gates and shift registers
Correct Option:
B
Question:-
Option (A)
0.19 ohm
Option (B)
3.48 ohm
Option (C)
1.46 ohm
Option (D)
2.43 ohm
Correct Option:
Question Solution:
w= p106 Þ f=5x105 Hz

d=(1/ Ö(nf s m))=(1/ Ö(n x5x105x3.5x10-7x m0))=120 m2

Rac=(1/a d w)

Since d is very small w=2nn outer

Rac=(60/(3.5x177x120x10-6x2nx12x10-3))-0.19 ohm
Question:-
Option (A)
gm=2.5mA/V and rn=15.625 k ohm
Option (B)
gm=40mA/V and rn=4.0 k ohm
Option (C)
gmn=2.5k ohm
Option (D)
gm40mA/V and rn=2.5 k ohm
Correct Option:
D
Question Solution:
Gm=IC/VT=1/25=40mA/V

Rx=bre=b/gm=100/40x10-3=2.5 k ohm
Question:-
Option (A)
a common emitter stage followed by a common base stage
Option (B)
a common base stage followed by an emitter follower
Option (C)
an emitter follower stage followed by a common emitter stage
Option (D)
a common base stage ro lowed by a common emitter stage
Correct Option:
A
Question:-
Option (A)
also has a pole at 1/2Ð30°
Option (B)
has a constant phase response over the z-plan: arg |H(z)|= const
Option (C)
is stable only ant causal
Option (D)
has a constant phase response over the unit circle : arg|H(eI ohm =const
Correct Option:
C
Question Solution:
For causal system if all the poles are inside the




Unit circle then system is stable and converse is true for anticausal system