This set of Radar Multiple Choice Questions & Answers (MCQs) focuses on “MTI Radar”.
1. What does MTI stand for?
a) Motion Target Indication
b) Moving Target Indicator
c) Movable Target Indicator
d) Moving Target Indication
View Answer
Explanation: MTI stands for Moving Target Indication. The MTI radar has a pulse repetition frequency low enough to not have range ambiguities from the equation Rum = c/fp. It does, however, have many ambiguities in the Doppler domain.
2. Which out of the following device is not used in the block diagram of an MTI radar?
a) Power amplifier
b) Mixer
c) Pulse modulator
d) RF amplifier
View Answer
Explanation: RF amplifier is not part of an MTI radar. Power amplifier is used since it can have high stability and is capable of high power, pulse modulator turns the amplifier on and off to generate the radar pulses and Mixer is used for changing the level and quality of the signal.
3. The local oscillator of an MTI radar’s super heterodyne receiver must be less stable than the local oscillator for a radar that does not employ Doppler.
a) True
b) False
View Answer
Explanation: The local oscillator of an MTI radar’s receiver must be more stable. This is because if the phase of the local oscillator were to change significantly between pulses, an uncalled clutter residue can result at the output of the delay-line canceler which might be mistaken for a moving target even though only clutter were present.
4. In the MTI block diagram, instead of an amplitude detector the IF stage is followed by ________
a) mixer
b) phase detector
c) video amplifier
d) duplexer
View Answer
Explanation: In MTI block diagram, the IF amplifier is followed by a phase sensitive detector instead of an amplitude detector. Due to this, the mixture of fc±fd received from the mixer to the IF amplifier will be deducted from the fc of Coho and in the end the result we’ll obtain is the Doppler frequency fd.
5. What does Coho stands for?
a) Compact Oscillator
b) Convolutional Oscillator
c) Oscillator Canceler
d) Coherent Oscillator
View Answer
Explanation: The name Coho stands for coherent oscillator to signify that it is the reference signal that has the phase of the transmitter signal. Coho is very stable continuous wave oscillator which constitutes the internal phase reference in case of a moving target indication.
6. The transmitter frequency is the sum of the Coho frequency and the _______
a) stalo frequency
b) delay frequency
c) reference frequency
d) doppler frequency
View Answer
Explanation: It is the sum of Coho frequency and Stalo frequency. The combination of the Stalo and Coho sometimes is called the receiver-exciter portion of the MTI radar. Using the receiver Stalo and Coho to also generate the transmitter signal insures better stability than if the functions were performed with two different sets of oscillators.
7. In order to separate the Doppler-shifted echo signals of moving targets from the unwanted echoes of stationary clutter, which out of the following filters delay line canceler acts as?
a) Band limit filter
b) High pass filter
c) Band pass filter
d) Low pass filter
View Answer
Explanation: In order to separate the Doppler-shifted echo signals of moving targets from the unwanted echoes of stationary clutter, the delay line canceler acts as a high pass filter. In this case, the Doppler filter might be a single delay line canceler but it is more likely to be one of several other more elaborate filters with greater capability.
8. Klystron is one of the preferred type of vacuum tube amplifier for MTI radar.
a) True
b) False
View Answer
Explanation: The Klystron and the travelling wave tube have usually been the preferred type of vacuum-tube amplifier for MTI radar. The crossed-field amplifier has also been used, but it is generally noisier (less stable) than other devices; hence it might not be capable of canceling large clutter echoes.
9. What is an optimum MTI filter used for?
a) To increase the stability of oscillator
b) To decrease the interference of clutter
c) To maximize the improvement factor
d) To decrease transmitter leakage
View Answer
Explanation: The optimum MTI filter is used to maximize the improvement factor. It can also be considered as one which maximizes the clutter attenuation. It happens that a close approximation to the optimum MTI filter is a transversal filter with binomial weights of alternating sign that has a frequency response function proportional to sinn (πfTp).
10. Before the development of high power klystron amplifier, which RF power generator was the most suitable at microwave frequencies?
a) Solid state oscillator
b) Magnetron oscillator
c) Crossed-field oscillator
d) Cyclotron oscillator
View Answer
Explanation: Before the development of high power klystron amplifier, the only suitable RF power generator at microwave frequencies was the magnetron oscillator. In an oscillator, the phase at the start of each pulse is random so that the receiver-exciter concept cannot be used.
Sanfoundry Global Education & Learning Series – Radar.
To practice all areas of Radar, here is complete set of Multiple Choice Questions and Answers.
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