23
3-36. What determines the length of time that a
nonsynchronous satellite in a circular
orbit will be in the zone of mutual
visibility?
1. Height of the orbit
2. Earth terminal antenna size
3. Down-link transmitter power
4. Up-link receiver sensitivity
3-37. Satellite communications systems are
being rapidly developed by the Navy for
which of the following reasons?
1. To replace microwave links
2. To relieve dependence on hf
communications
3. To reduce procurement and
development costs
4. To replace all physically large size
equipment
3-38. In an mf transmitter, the frequency
generator is used during which of the
following modes of operation?
1. AM
2. Fm
3. Cw
4. Fsk
3-39. The pre-ipa and ipa in an mf transmitter
are which of the following types?
1. Linear, tuned
2. Linear, untuned
3. Non-linear, tuned
4. Non-linear, untuned
3-40. Of the following communications system
components, which one is a device that is
nonradiating, absorbs rf, and has the
characteristic impedance of the antenna?
1. Helix
2. Dummy load
3. Rf tuning unit
4. Frequency synthesizer
3-41. Which of the following antenna arrays
consists of quarter-wave, vertically
polarized stubs?
1. Broadside
2. Parasitic
3. Top-hat
4. Triatic
IN ANSWERING QUESTIONS 3-42
THROUGH 3-44, REFER TO THE MEDIUM
FREQUENCY AND BELOW RECEIVER
COVERED IN CHAPTER 5.
3-42. With one exception, the receiver has the
same circuitry as any high frequency
receiver. What is the one exception?
1. The components are doubled up
2. The local oscillator is eliminated
3. The radio-frequency amplifier is
replaced by a video amplifier
4. The audio-frequency amplifier is
replaced by a traveling-wave tube
3-43. The rejection of input frequencies above
900-kilohertz is performed by which of
the following circuits?
1. An attenuator
2. A video amplifier
3. A low-pass filter
4. A calibration oscillator
3-44. The demodulation of ssb, cw, and fsk
signals is performed by which of the
following circuits?
1. An fm detector
2. A phase splitter
3. An audio amplifier
4. A product detector
