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| 1 | |
The outputs of a differential amplifier taken from collectors to ground are |
| | A) | in phase |
| | B) | 45° out of phase |
| | C) | 90° out of phase |
| | D) | 180° out of phase |
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| 2 | |
Which of the following is not an advantage of using a differential amplifier as an amplitude modulator? |
| | A) | high gain |
| | B) | excellent selectivity |
| | C) | good linearity |
| | D) | can be modulated 100 percent |
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| 3 | |
In high-level AM, the modulator varies the voltage and power in the |
| | A) | carrier oscillator |
| | B) | audio amplifier |
| | C) | intermediate RF amplifier |
| | D) | final RF amplifier |
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| 4 | |
If a class C amplifier has an input of 1000 W, the modulator must be able to deliver |
| | A) | 100 W |
| | B) | 200 W |
| | C) | 400 W |
| | D) | 500 W |
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| 5 | |
Circuits that accept modulated signals and recover the original modulating information are called |
| | A) | modulators |
| | B) | detectors |
| | C) | nonlinear circuits |
| | D) | balanced filters |
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| 6 | |
The crystal component of the crystal radio receivers that were widely used in the past is the |
| | A) | capacitor |
| | B) | transistor |
| | C) | diode |
| | D) | integrated circuit |
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| 7 | |
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How is the noninverted AM output of positive half-cycles in the circuit shown above fed to the load? |
| | A) | clock turns on switch A |
| | B) | clock turns on switch B |
| | C) | inverting amp turns on |
| | D) | noninverting amp turns off |
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| 8 | |
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What is the result (output) for the circuit shown above? |
| | A) | half-wave rectification of the signal |
| | B) | full-wave rectification of the signal |
| | C) | dc |
| | D) | ac |
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| 9 | |
A circuit that generates a DSB signal, suppresses the carrier and leaves only sum and difference frequencies at the output is the |
| | A) | unbalanced detector |
| | B) | balanced modulator |
| | C) | carrier recovery circuit |
| | D) | demodulator |
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| 10 | |
In DSB and SSB, the carrier that was suppressed at the DSB and SSB transmitter |
| | A) | must be reinserted at the receiver |
| | B) | must be transmitted after the signal was received |
| | C) | must be replaced by a pilot carrier |
| | D) | must be lower than 1500 kHz |
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