| 1. | If the total power of an amplitude modulated signals is 600 W and the carrier power is 400W, the modulation index is ? | |
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0.75
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0.5
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0.25
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1
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Report Question| 2. | What would be the effect on transmitted power of an AM wave if its modulation index changes to 1 from 0 ? | |
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Will be halved
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Will remain unchanged
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Will be quadrupled
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Will be increased by 50%
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| 3. | On increasing modulation index : ? | |
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Transmitted power is constant in AM but increases in FM
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Transmitted power constant in FM but increases in AM
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Transmitted power decreases in both FM and AM
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Transmitted power increases in both FM and AM
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| 4. | In TV, video signals are transmitted through ? | |
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Frequency modulation
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Pulse modulation
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Amplitude modulation
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Phase modulation
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| 5. | A carrier voltage is simultaneously modulated by two sine waves causing modulation indices of 0.4 and 0.3. the overall modulation index is ? | |
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0.35
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0.7
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0.5
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Cannot be calculated unless the phase relations are known
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| 6. | Which one of the following is used for the detection of AM-DSB-SC signal ? | |
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Ratio detector
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Foster-Seeley discriminator
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Product demodulator
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Balanced – slope detector
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| 7. | Absorption of Ratio waves in atmosphere depends on ? | |
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Frequency of waves
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Distance from transmitter
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Polarization of waves
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Polarization of atmosphere
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| 8. | A 20kW carrier is sinusoid ally modulated by two carriers corresponding to a modulation index of 20% and 40 % respectively. The total radiated power is ? | |
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25kW
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17kW
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15kW
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22kW
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| 9. | For which of the following reasons, amplitude modulation is used for broadcasting ? | |
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It is more immune to noise
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It use avoids receiver complexity
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It requires less transmitting power
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Only the positive peak of the carrier wave varies with the modulating signal
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| 10. | The input to a coherent detector is DSB-SC signal plus noise. The noise at the detector output is ? | |
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The in-phase component
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The Quadrature-component
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Zero
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The envelope
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