69 lines
2.6 KiB
Markdown
69 lines
2.6 KiB
Markdown
G7B – Digital circuits; amplifiers and oscillators
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- [[G7B01]] (B)
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What is the purpose of neutralizing an amplifier? #card
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- A. To limit the modulation index
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- B. To eliminate self-oscillations
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- C. To cut off the final amplifier during standby periods
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- D. To keep the carrier on frequency
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- [[G7B02]] (D)
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Which of these classes of amplifiers has the highest efficiency? #card
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- A. Class A
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- B. Class B
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- C. Class AB
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- D. Class C
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- [[G7B03]] (B)
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Which of the following describes the function of a two-input AND gate? #card
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- A. Output is high when either or both inputs are low
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- B. Output is high only when both inputs are high
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- C. Output is low when either or both inputs are high
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- D. Output is low only when both inputs are high
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- [[G7B04]] (A)
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In a Class A amplifier, what percentage of the time does the amplifying device conduct? #card
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- A. 100%
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- B. More than 50% but less than 100%
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- C. 50%
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- D. Less than 50%
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- [[G7B05]] (C)
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How many states does a 3-bit binary counter have? #card
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- A. 3
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- B. 6
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- C. 8
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- D. 16
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- [[G7B06]] (A)
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What is a shift register? #card
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- A. A clocked array of circuits that passes data in steps along the array
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- B. An array of operational amplifiers used for tri-state arithmetic operations
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- C. A digital mixer
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- D. An analog mixer
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- [[G7B07]] (D)
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Which of the following are basic components of a sine wave oscillator? #card
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- A. An amplifier and a divider
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- B. A frequency multiplier and a mixer
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- C. A circulator and a filter operating in a feed-forward loop
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- D. A filter and an amplifier operating in a feedback loop
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- [[G7B08]] (B)
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How is the efficiency of an RF power amplifier determined? #card
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- A. Divide the DC input power by the DC output power
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- B. Divide the RF output power by the DC input power
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- C. Multiply the RF input power by the reciprocal of the RF output power
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- D. Add the RF input power to the DC output power
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- [[G7B09]] (C)
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What determines the frequency of an LC oscillator? #card
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- A. The number of stages in the counter
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- B. The number of stages in the divider
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- C. The inductance and capacitance in the tank circuit
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- D. The time delay of the lag circuit
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- [[G7B10]] (B)
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Which of the following describes a linear amplifier? #card
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- A. Any RF power amplifier used in conjunction with an amateur transceiver
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- B. An amplifier in which the output preserves the input waveform
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- C. A Class C high efficiency amplifier
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- D. An amplifier used as a frequency multiplier
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- [[G7B11]] (B)
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For which of the following modes is a Class C power stage appropriate for amplifying a modulated signal? #card
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- A. SSB
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- B. FM
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- C. AM
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- D. All these choices are correct
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