G7B – Digital circuits; amplifiers and oscillators

- [[G7B01]] (B)
What is the purpose of neutralizing an amplifier? #card
	- 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? #card
	- 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? #card
	- 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? #card
	- 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? #card
	- A. 3
	- B. 6
	- C. 8
	- D. 16
- [[G7B06]] (A)
What is a shift register? #card
	- 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? #card
	- 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? #card
	- 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? #card
	- 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? #card
	- 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? #card
	- A. SSB
	- B. FM
	- C. AM
	- D. All these choices are correct