| 1. | Shot noise current is directly proportional to ? | |
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Bandwidth of the system
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Square of the bandwidth
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1/(Square root of bandwidth)
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Square root of the bandwidth
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Report Question| 2. | For efficient radiation and reception, the transmitting and receiving antennas would have to have comparable to ………………. ? | |
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Quarter wavelength
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Half wavelength
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3/4th wavelength
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Equal wavelength
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| 3. | The intrinsic impedance of free space is ? | |
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73
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377
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75
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120
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| 4. | The available power required at a receiving antenna is 106 Watts. Transmitting and receiving antennas have gain of 40 dB each. The carrier frequency is 4 GHz and the distance between them is 30 miles. The required transmitter power is ? | |
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0.64 W
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0.74 W
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0.78 W
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0.32 W
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| 5. | An antenna has maximum radiation intensity Umax = 10 Watt/Sr and average radiation intensity Uavg = 4.5 Watt/Sr. if the efficiency of the antenna is given as nr = 95%, the input power of the antenna is ? | |
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2.222 Watt
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59.52 Watt
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12.11 Watt
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55.55 Watt
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| 6. | The gain of a parabolic dish antenna of I m diameter and 80 % efficiency at 9.5GHz is ? | |
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78 dB
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39 dB
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40 dB
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45 dB
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| 7. | A 1mW video signal having a bandwidth of 100MHz is transmitted to a receiver through a cable that has 40dB loss. If the effective one-sided noise spectral density at the receiver is 10-20 Watt/Hz, then signal-to-noise ratio at the receiver is ? | |
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30 dB
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50 dB
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60 dB
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40 dB
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| 8. | What would be the antenna efficiency for a transmit antenna with a radiation resistance Rr = 25 Ohm and an effective antenna resistance Re=15 ohm ? | |
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25.6%
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62.5%
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70.2%
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50.26%
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| 9. | In a communication system at 300 MHz, the receiving antenna gain is 8 dBi, the transmitting antenna gain is 10 dBi and the transmitting power level is 25 watts, the distance between the transmitter and the receiver is 1 km, the power received at the receiving antenna port (assuming the propagation medium is loss-less) ? | |
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9.97
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1 mW
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0.0997 Nw
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99.7 nW
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| 10. | Which of the following noise must be considered at high frequencies (microwave frequencies) ? | |
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Transit time noise
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Shot noise
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Random noise
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Impulse noise
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