9
2-9. Which of the following characteristics is
NOT a requirement of a basic radar
system timing circuit?
1. It must be free-funning
2. Frequency must be variable
3. It must develop random frequencies
4. It should provide a stable frequency
2-10. Which of the following circuits converts
square waves to positive and negative
triggers?
1. A negative limiter
2. A positive limiter
3. A long-time-constant RC
differentiator
4. A short-time-constant RC
differentiator
2-11. Which of the following circuits is used to
remove either the negative or positive
triggers from the output of a sine-wave
oscillator?
1. A clipper
2. A limiter
3. An LC network
4. A differentiator
2-12. When the master oscillator in a
multivibrator timer is asymmetrical, the
output of the master oscillator is in the
form of
1. rectangular waves
2. negative pulses
3. square waves
4. sine waves
2-13. The positive and negative output pulses
of the astable multivibrator are sent to the
indicator for which of the following
purposes?
1. To intensify the crt beam
2. To gate the range-marker generator
3. Both 1 and 2 above
4. To gate the transmitter output
2-14. Which of the following oscillators
generates sharp trigger pulses without
additional circuitry?
1. Sine-wave oscillator
2. Wien-bridge oscillator
3. One-shot multivibrator
4. Single-swing blocking oscillator
2-15. A radar transmitter is triggered directly
by high voltage pulses from what unit?
1. The timer
2. The antenna
3. The indicator
4. The modulator
2-16. The peak power of a transmitted rf pulse
depends on which of the following
factors?
1. Width of the modulator pulse
2. Amplitude of the modulator pulse
3. Prf of trigger pulses from the timer
4. Delay time between trigger and
modulator pulse outputs
2-17. The transmitter range timing circuit must
be triggered at the instant the transmitted
pulse leaves the transmitter. For which
of the following reasons is this timing so
important?
1. To ensure accurate range
2. The ensure long range targets are
detected
3. To ensure that the target is "painted"
on the crt by each transmitted pulse
4. To keep the magnetron oscillating at
a fixed frequency
2-18. For proper operation of the magnetron,
the modulator pulse must have which of
the following characteristics?
1. A flat top
2. A steep leading edge
3. A steep trailing edge
4. All of the above
