Modulation

31. Overmodulation results in _________

1. Weakening of the signal
2. Excessive carrier power
3. Distortion
4. None of the above

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32. Superhertodyne principle refers to

1. Using a large number of amplifier stages
2. Using a push-pull circuit
3. Obtaining lower fixed intermediate frequency
4. None of the above

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33. The diode detector in an AM radio receiver is usually found _________

1. Before the first RF stage
2. After the first RF stage
3. After several stages of amplification
4. None of the above

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34. The function of ferrite antenna is to _________

1. Reduce stray capacitance
2. Stabilise d.c. bias
3. Increase the Q of tuned circuit
4. Reduce noise

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35. The IF is 455 kHz. If the radio receiver is tuned to 855 kHz, the local oscillator frequency is _________

1. 455 kHz
2. 1310 kHz
3. 1500 kHz
4. 1520 kHz

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36. The letters AVC stand for _________

1. Audio voltage control
2. Abrupt voltage control
3. Automatic volume control
4. Automatic voltage control

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37. The major advantage of FM over AM is _________

1. Reception is less noisy
2. Higher carrier frequency
3. Smaller bandwidth
4. Small frequency deviation

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38. The signal voltage induced in the aerial of a radio receiver is of the order of _________

1. mV
2. μV
3. V
4. None of the above

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39. The superhetrodyne principle provides selectivity at _________ stage

1. RF
2. IF
3. audio
4. Before RF

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40. When the modulating signal controls the frequency of the carrier, we get _________

1. Phase modulation
2. Amplitude modulation
3. Frequency modulation
4. May be any one of the above

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