Electronics and Communication Engineering - Communication Systems

31. 

In standing wave pattern on a transmission line

A. voltage and current nodes coincide
B. voltage and current antinodes coincide
C. voltage nodes and current antinodes as well as current nodes and voltage antinodes coincide
D. both (a) and (b)

Answer: Option C

Explanation:

When standing wave is set up voltage maxima and current minima and voltage minima and current maxima coincide.


32. 

If the bandwidth is increased by 2, the γFM γAM (where γ is the ratio of SNR of output to SNR at input, FM is frequency modulation and AM is amplitude modulation) is increased by a factor of

A. 2
B. 3
C. 4
D. 6

Answer: Option C

Explanation:

Doubling of frequency increase SNR in frequency modulation by 4. It has no effect in AM.


33. 

In the figure , the output y(t) will be

A.
B.
C.
D.

Answer: Option C

Explanation:


34. 

A carrier wave carries information.

A. True
B. False

Answer: Option B

Explanation:

Carrier does not have any information.


35. 

Frequency shift keying is used mostly in

A. telegraphy
B. telephony
C. satellite communication
D. radio transmission

Answer: Option A

Explanation:

Frequency shift keying (FSK) is a system of frequency modulation used in telegraphy.