56. In satellite communication 6/4 GHz band by the disadvantages :
(a) There is no absorption by the rain
(b) Sky noise is low
(c) More interference from others users
(d) Fewest propagation problems
57. One of the following can not be used to demodulate SSB :
(a) product detector
(b) diode balanced modulator
(c) bipolar transistor balanced modulator
(d) complete phase shift generator
58. The commonly employed filter in SSB generation is :
(a) high pass filter
(b) mechanical filter
(c) RC filter
(d) LC filter
59. The following is an indirect method of generating FM :
(a) Reactive FM modulator
(b) Armstrong modulation
(c) Varactor diode modulation
(d) Reactance BJT modulator
60. The modulation index of an AM signal is increased from 0 to 1. The carrier power :
(a) Remains unchanged
(b) Gets doubled
(c) Increased by 50%
(d) Gets quadrupled
Related Posts
Angle Modulation » Exercise - 15. The frequency of the stereo sub carrier signal in FM broadcasting is - (a) 19 kHz (b) 38 kHz (c) 50 kHz (d) 76 kHz- Introduction to Satellite Communication » Exercise - 130. The carrier frequency component of an amplitude-modulated signal contains no information but is of ….. amplitude than the side band. (a) Smaller (b) Greater (c) Either of the above (d) None of the above
- Introduction to Satellite Communication » Exercise - 1 1. An active satellite carriers : (a) Antenna system (b) Transmitter (c) Receiver (d) All of the above 2. A passive satellite : (a) Amplifier the signal (b) Reflects the signal (c) Absorbs the signal (d) None of above 3. Marisat Satellites are used for : (a) TV transmission (b) Weather forecasts (c) Ship to share communication (d) Satellite to satellite communication 4. If the maximum value of electron density is 1.24 x 106 cm^-3 the critical frequency for reflection at vertical incidence will be nearly : (a) 1 MHz (b) 5 MHz (c) 7.5 MHz (d) 5 MHz 5. An active satellite has : (a) Antenna system (b) Antenna system transmitter and receiver (c) Antenna system, transmitter, receiver and power supply (d) only metallic baloon 6. In satellite communication, modulation used is : (a) AM (b) PAM (c) PCM (d) FM 7. For global communication the number of satellite needed is : (a) 1 (b) 2 (c) 3 (d) 10 8. Satellite operate in the frequency range : (a) MF (b) HF (c) VHF (d) VHF and UHF 9. A satellite used for international communication is known as : (a) Comsat (b) Domsat (c) Intelsat (d) None of these 10. The source of energy for…
- Angle Modulation » Exercise - 1 1. In FM the carrier deviation is determined by – (a) Modulating (b) Frequency (c) Either of the above (d) None of the above 2. Pre- emphasis is used to amplify - (a) Low frequency (b) High frequency (c) Both a and b above (d) None of the above 3. In FM - (a) Noise decreases by increasing deviation (b) Noise decreases by decreases deviation (c) Noise decreases by maintaining deviation constant (d) None of the above 4. Which of the following oscillator is not in FM - (a) Crystal oscillator (b) Hartley oscillator (c) Colpitts oscillator (d) All of the above 5. The frequency of the stereo sub carrier signal in FM broadcasting is - (a) 19 kHz (b) 38 kHz (c) 50 kHz (d) 76 kHz 6. The difference between phase and frequency modulation : (a) Lies in the different definition of the modulation index (b) Is too great to make the two systems compatible (c) Is purely theoretical because they are the same in practice (d) Lies in the poorer radio response of phase modulation index 7. Which one of the following is not necessarily an advantage of FM over AM ? (a) Better noise immunity is provided (b)…
- Introduction to Satellite Communication » Exercise - 280. Indicate the fields statement regarding the advantages of SSB over double side band, full carrier AM : (a) more channel space is available (b) the signal is more noise resistant (c) transmitter circuit must be more stable, giving better reception (d) much less power is required for the same signal strength