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