IndiaBIX

Electronics and Communication Engineering - Communication Systems

Exercise : Communication Systems - Section 3
16.
The number of channels in a stereophonic system is
8
4
2
1
Answer: Option
Explanation:

Left and right channels.

17.
When the carrier is unmodulated, a certain transmitter radiates 9 kW when the carrier is sinusoidally modulated the transmitter radiates 10.125 kW. The modulation index will be
0.1
10.15
0.4
0.5
Answer: Option
Explanation:

.

18.
A signal x(t) = 100 cos (24p x 103t) is ideally sampled with a sampling period of 50 μ sec and then passed through an ideal low pass filter with cut off frequency of 15 kHz Which of the following frequencies are present at the filter output?
12 kHz only
8 kHz only
12 kHz and 9 kHz
12 kHz and 8 kHz
Answer: Option
Explanation:

Frequency pass by L.P.F. are, fc fs - fc

12 kHz, 8 kHz.

19.
A sinusoidal voltage of 2 kV peak value is amplitude modulated to give 20% modulation. The peak value of each side band term is
400 V
200 V
100 V
800 V
Answer: Option
Explanation:

.

20.
Consider the following reasons for using antenna coupler
  1. To prevent illegal radiation of spurious frequencies
  2. To tune out reactive components of antenna impedance
  3. To have correct value of load impedance for transmitter.
Which of the above are correct?
1, 2, 3
1, 2
1 only
2, 3
Answer: Option
Explanation:

All the three are correct.

Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers