Electronics and Communication Engineering - Communication Systems

26.
The name modem is a contraction of terms modulator demodulator.
True
False
Answer: Option
Explanation:

Baudot code is 5 bit code.


27.
The use of SSB
halves the bandwidth required for transmission
does not affect the bandwidth for transmission
decreases the bandwidth required for transmission by 25%
decreases the bandwidth required for transmission by 66.6%
Answer: Option
Explanation:

One side band is eliminated in SSB.

Therefore bandwidth is halved.


28.
If a signal voltage Vs is accompanied by a noise voltage Vn the signal to noise ratio is
Answer: Option
Explanation:

Power is proportional to V2.


29.
Video signals are transmitted through
amplitude modulation
frequency modulation
either amplitude or frequency modulation
neither amplitude nor frequency modulation
Answer: Option
Explanation:

Because of large bandwidth requirement, modulation of video signals is possible only by amplitude modulation.


30.
A TV receiver has 20 kV EHT supply and total beam current (for 3 electron guns) of 1500 μA. The power handled by IHVT is
3 W
30 W
300 W
0.3 W
Answer: Option
Explanation:

P = 20 x 103 x 1500 x 10-6 = 30 W.