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
6. Commercial Frequency deviation of FM is
8. A modem is classified as low speed if data rate handled is
9. In Pulse Code Modulation system
10. The main function of a balanced modulator is to
11. Which of the following does not cause losses in optical fibre cables?
12. A buffer amplifier is
13. For a given carrier wave, maximum undistorted power is transmitted when value of modulation is
14. Full duplex operation permits transmission in both directions at the same time.
15. In TV systems, equalising pulses are sent during
16. For a plate-modulated class C amplifier the plate supply voltage is E. The maximum plate cathode voltage could be almost high as
17. In Modulation, “carrier” is
18. 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.
19. The modulation index of an FM is changed from 0 to 1. How does the transmitted power change?
20. In case of frequency modulation, modulating voltage remains constant if the modulating frequency is lowered, then
21. It is found that a ship to ship communication suffers from fading. This can be avoided by using
22. 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.
23. In a FM receiver, amplitude limiter
24. Under ordinary circumstances, impulse noise can be reduced in
25. 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
26. 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
27. For a low level AM system, the amplifiers modulated stage must be
28. In case of low level amplitude modulation system, the amplifiers following the modulated stage must be
29. An FM radio receiver which is tuned to a 91.6 MHz broadcast station may receive an image frequency of __________ MHz.
30. Skip distance depends on time of day and angle of incidence.
31. If sampling is done at the rate of 10 kHz. The bandwidth required is
32. In practical commercial FM system, channel bandwidth is
33. In EM waves, polarization
34. 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
35. If output power of a radio receiver is doubled, its volume is increased by __________ dB.
36. As per Shannon-Hartley theorem, a noise less Gaussian channel has
37. The direction of rotation of a CD is
38. What is the purpose of peak clipper circuits in radio transmitters?
39. The characteristic impedance of a twin wire feeder used for TV signals is about
40. SSB can be generated by
41. Which of the following is used to generate PDM?
42. The frequency range of 300 kHz to 3000 kHz is known as
43. When the length of antenna is a whole wavelength
44. A telephone channel requires a bandwidth of about
45. Fourier analysis indicate that a square wave can be represented as
46. The colour of an object is decided by
47. Which of the following is an indirect way of generating FM?
48. Which of the following is a digital modulation technique?
49. In a TV receiver antenna the length of reflector rod
50. One of the advantages of base modulation over collector modulation of a transistor class C amplifier is
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