Following are some of the multiple choice questions on the Communication Systems with answers that will help the students in developing their knowledge.
Communication Systems MCQ
3. VSB modulation is preferred in TV because
4. For attenuation of high frequencies we should use
5. A woofer should be fed from the input through a
7. In Pulse Code Modulation system
8. A modem is classified as low speed if data rate handled is
9. The main function of a balanced modulator is to
10. A cordless telephone using separate frequencies for transmission in base and portable units is known as
11. Which of the following does not cause losses in optical fibre cables?
12. A buffer amplifier is
13. Commercial Frequency deviation of FM is
14. If output power of a radio receiver is doubled, its volume is increased by __________ dB.
15. Which of the following is used to generate PDM?
16. When the length of antenna is a whole wavelength
17. Which of the following is a digital modulation technique?
18. For telegraphy the most commonly used modulation system is
19. The disadvantage of FM over AM is that
20. A telephone channel requires a bandwidth of about
21. Which of the following is an indirect way of generating FM?
22. One of the advantages of base modulation over collector modulation of a transistor class C amplifier is
23. The maximum power output of a standard A earth station over the total band allocated to satellite communication is about
24. As per Shannon-Hartley theorem, a noise less Gaussian channel has
25. An audio signal (say from 50 Hz to 10000 Hz) is frequency translated by a carrier having a frequency of 106 Hz. The values of initial (without frequency translation) and final (after frequency translation) fractional change in frequency from one band edge to the other are
26. Skip distance depends on time of day and angle of incidence.
27. In practical commercial FM system, channel bandwidth is
28. If sampling is done at the rate of 10 kHz. The bandwidth required is
29. In EM waves, polarization
30. It is found that a ship to ship communication suffers from fading. This can be avoided by using
31. An FM radio receiver which is tuned to a 91.6 MHz broadcast station may receive an image frequency of __________ MHz.
32. In case of low level amplitude modulation system, the amplifiers following the modulated stage must be
33. For a low level AM system, the amplifiers modulated stage must be
34. A three stage telephone switching structure is to have 128 input and 128 output terminals. There are 16 first stage and 16 third stage matrices. To avoid blocking the number of intermediate paths required is
35. A zero mean white Gaussian noise is passed through an ideal low pass filter of bandwidth 10 kHz. The output of the samples so obtained would be
36. Under ordinary circumstances, impulse noise can be reduced in
37. In a FM receiver, amplitude limiter
38. Assertion (A): In FM the frequency of the carrier is varied by the modulating voltageReason (R): FM and PM are two forms of angle modulation.
39. Full duplex operation permits transmission in both directions at the same time.
40. In case of frequency modulation, modulating voltage remains constant if the modulating frequency is lowered, then
41. The modulation index of an FM is changed from 0 to 1. How does the transmitted power change?
42. For a given carrier wave, maximum undistorted power is transmitted when value of modulation is
43. In TV systems, equalising pulses are sent during
44. For a plate-modulated class C amplifier the plate supply voltage is E. The maximum plate cathode voltage could be almost high as
45. In Modulation, “carrier” is
46. If in a broadcasting studio, a 1000 kHz carrier is modulated by an audio signal of frequency range 100-5000 kHz, the width of channel is __________ kHz.
47. Which one of the following is analog?
48. For AM receivers the standard IF frequency is
49. FM transmitting and receiving equipment as compared to AM equipment is
50. Leak type bias is used in plate modulated class C amplifier to
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