G7B: Digital circuits (gates, flip-flops, shift registers); amplifiers and oscillators
G7B01:
Which of the following describes a "flip-flop" circuit?
A digital circuit with two stable states
A transmit-receive circuit
An RF limiter
A voice-operated switch
G7B02:
Why do digital circuits use the binary number system?
Binary "ones" and "zeros" are easy to represent with an "on" or "off" state
The binary number system is most accurate
Binary numbers are more compatible with analog circuitry
All of these answers are correct
G7B03:
What is the output of a two-input NAND gate, given both inputs are "one"?
Zero
Two
One
Minus One
G7B04:
What is the output of a NOR gate given that both inputs are "zero"?
One
Zero
Minus one
The opposite from the previous state
G7B05:
How many states are there in a 3-bit binary counter?
8
3
6
16
G7B06:
What is a shift register?
A clocked array of circuits that passes data in steps along the array
An array of operational amplifiers used for tri-state arithmetic operations
A digital mixer
An analog mixer
G7B07:
What are the basic components of virtually all oscillators?
A filter and an amplifier operating in a feedback loop
An amplifier and a divider
A frequency multiplier and a mixer
A circulator and a filter operating in a feed-forward loop
G7B08:
What determines the frequency of an RC oscillator?
The phase shift of the RC feedback circuit
The ratio of the capacitors in the feedback loop
The value of the inductor in the tank circuit
The gain of the amplifier
G7B09:
What determines the frequency of an LC oscillator?
The inductance and capacitance in the tank circuit
The number of stages in the counter
The number of stages in the divider
The time delay of the lag circuit
G7B10:
Which of the following is a characteristic of a Class A amplifier?
Low distortion
Low standby power
High Efficiency
No need for bias
G7B11:
For which of the following modes is a Class C power stage appropriate for amplifying a modulated signal?
CW
SSB
AM
All of these answers are correct
G7B12:
Which of the following is an advantage of a Class C amplifier?
High efficiency
Linear operation
No need for tuned circuits
All of these answers are correct
G7B13:
How is the efficiency of an RF power amplifier determined?
Divide the RF output power by the DC input power
Divide the DC input power by the DC output power
Multiply the RF input power by the reciprocal of the RF output power
Add the RF input power to the DC output power
G7B14:
Which of the following describes a linear amplifier?
An amplifier whose output preserves the input waveform
Any RF power amplifier used in conjunction with an amateur transceiver
A Class C high efficiency amplifier
An amplifier used as a frequency multiplier
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