This set of Radar Multiple Choice Questions & Answers (MCQs) focuses on “System Losses”.
1. On what parameters system losses depends on?
a) The overall usage of a radar
b) Radar design and how the radar is maintained
c) The cost and user friendliness
d) The max power output
View Answer
Explanation: The system losses depend on the radar design and how the radar is maintained. System losses, Ls is inserted in the denominator of the radar equation. It is the reciprocal of efficiency. The two terms (loss and efficiency) are sometimes used interchangeably.
2. Since the same transmission line is used for both transmission and reception, the loss to be inserted in the radar equation is ________
a) one way loss
b) twice the one way loss
c) thrice the one way loss
d) no loss
View Answer
Explanation: The loss to be inserted in radar is twice the one way loss. At lower radar frequencies, the transmission line introduces little loss unless its length is exceptionally long. At higher frequencies attenuation may not always be small and may have to be taken into account.
3. A radar have a waveguide shutter with some insertion loss.
a) True
b) False
View Answer
Explanation: It is true that radar has a waveguide shutter with some insertion loss that closes when the radar is shut down so as to protect the receiver from extraneous high power signals when its duplexer is not activated.
4. On what parameter loss introduced by a radome depends on?
a) Type and the radar frequency
b) Cost and maintenance
c) Power generated
d) Power loss
View Answer
Explanation: Loss introduced by a radome depends on the type and the radar frequency. A typical ground based metal space frame radome might have a two way transmission loss of 1.2 dB at frequencies ranging from L to X band.
5. Which of the following is not a part of Signal processing losses?
a) Limiting loss
b) Sampling loss
c) Straddling loss
d) Power loss
View Answer
Explanation: Limiting loss, sampling loss and straddling loss are the part of signal processing loss. Sophisticated signal processing is prevalent in modern radars and is very important for detecting targets in clutter and in extracting information from radar echo signals.
6. What is the use of a limiter in a radar receiver?
a) Remove amplitude fluctuations
b) To increase power gain
c) To improve signal to noise ratio
d) To enhance power loss
View Answer
Explanation: Limiters are used in radar to remove amplitude fluctuations in the signal, this is an example of pulse compression processing. The so called Dicke-fix, an electronic counter-countermeasure to reduce the effects of impulsive noise, employs a hard limiter.
7. The difference between the sampled value and the maximum pulse amplitude represents a ________
a) limiting loss
b) doppler loss
c) sampling loss
d) frequency loss
View Answer
Explanation: The difference between the sampled value and the maximum pulse amplitude represents a sampling loss. The loss is about 2 dB when the sampling is at a rate of once per pulse width. The larger values occur with high probability of detection.
8. Which out of the following are sometimes used in an MTI radar when the pulses are processed in batches?
a) Fill pulses
b) Digital pulses
c) Analog pulses
d) Sampling pulses
View Answer
Explanation: Fill pulses are sometimes used in an MTI radar when the pulses are processed in batches as in the MTD radar. They are also sometimes used with high pulse repetition frequency Doppler radar to avoid effects of multiple time around clutter echoes.
9. If the radar were to integrate additional noise samples along with signal plus noise pulses, the added noise would result in a degradation called the _________
a) degradation loss
b) propagation loss
c) operator loss
d) collapsing loss
View Answer
Explanation: If the radar were to integrate additional noise samples along with signal plus noise pulses, the added noise would result in a degradation called the collapsing loss. An example is in a 3D radar that has a stack of multiple independent pencil beams in elevation.
10. Propagation effects can only decrease the free space range.
a) True
b) False
View Answer
Explanation: Propagation effects can increase the free space range as well as decrease it. The major effects of propagation on radar performance are a reflection from the earth’s surface, refraction, propagation in atmospheric ducts and attenuation in the clear atmosphere.
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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