14
2-50. Tuning a tunnel-diode oscillator by
changing the capacitance of the tuned
circuit can be accomplished by which of
the following tuning methods?
1. Bias tuning
2. Slot tuning
3. Current tuning
4. Varactor tuning
2-51. In the reflection-type, circulator-coupled
tunnel-diode amplifier, what component
prevents feedback to the tuned input
circuit?
1. The circulator
2. The output loop
3. The tuned cavity
4. The tunnel diode
2-52. Stability is a problem in which, if any, of
the following tunnel-diode frequency
converters?
1. High-gain converter
2. Unity-gain converter
3. Conversion-loss converter
4. None of the above
2-53. The varactor is a type of pn junction that
acts as which of the following types of
electronic devices?
1. Fixed resistor
2. Fixed capacitor
3. Variable resistor
4. Variable capacitor
2-54. What is the most important feature of the
parametric amplifier?
1. Low noise
2. High gain
3. Power output
4. Frequency range
Figure 2A.—Voltage amplification circuit.
IN ANSWERING QUESTION 2-55, REFER
TO FIGURE 2A.
2-55. How is amplification accomplished in the
circuit?
1. By opening the switch
2. By varying the frequency
3. By varying the resistance
4. By varying the capacitance
2-56. In a nondegenerative parametric
amplifier, how does the pump frequency
compare to the input signal frequency?
1. The pump frequency is half the input
signal frequency
2. The pump frequency is double the
input signal frequency
3. The pump frequency is more than
double the input signal
4. The pump frequency is equal to the
input signal frequency
2-57. In a nondegenerative parametric
amplifier with a pump frequency of 12
gigahertz and an idler frequency of 9
gigahertz, what is the input signal
frequency?
1. 3 gigahertz
2. 18 gigahertz
3. 21 gigahertz
4. 108 gigahertz
