11
2-28. What modulator circuit characteristic
determines the charging rate of the
storage element?
1. Resistance
2. Capacitance
3. Charging impedance
4. Pulse-repetition frequency
2-29. Which of the following types of
instability are common to magnetron
oscillators?
1. Mode skipping
2. Mode shifting
3. Both 1 and 2 above
4. Magnetic fluctuation
2-30. Which of the following magnetron
characteristics can be caused by low
magnetic field strength?
1. Low power output
2. Excessive plate current
3. Incorrect operating frequency
4. All of the above
2-31. Which of the following maximum tuning
ranges is typical for a tunable
magnetron?
1. 10 percent around the center
frequency
2. 5 percent around the center
frequency
3. 1 to 5 percent above the center
frequency
4. 1 to 10 percent below the center
frequency
2-32. Compared to the keyed-oscillator
transmitter, power-amplifier transmitters
are used more often with mti radar
systems because power-amplifier
transmitters provide
1. better stability
2. lower output power
3. higher output power
4. greater frequency range
2-33. Which of the following tubes should be
used as the power amplifier in a radar
transmitter?
1. The magnetron
2. The thyratron
3. The reflex klystron
4. The multicavity klystron
2-34. Which of the following components
determines the pulse width of a power-
amplifier transmitter?
1. The modulator
2. The mixer-amplifier
3. The local oscillator
4. The power-amplifier tube
2-35. The intermediate stages of a power-
amplifier transmitter have operating
power only during which of the
following times?
1. When the coherent rf pulse is applied
2. When the local oscillator signal is
applied
3. During the time the modulator pulse
is applied
4. Immediately after the coherent rf
pulse is removed
2-36. Using a frequency synthesizer instead of
a heterodyning mixer as the frequency
generating source for a power-amplifier
transmitter is an advantage because the
frequency synthesizer
1. is more stable
2. is simpler to construct
3. produces a single frequency
4. produces discrete frequencies over a
wide band
