HIGHLIGHTED-Microwave-Communications.pdf

The power that leaks out of the back and sides of the

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250. The power that leaks out of the back and sides of the transmit antenna interfering with the signal entering with the signal entering the input of a nearby receive antenna. a) ringaround b) ringabout c) roundabout d) turnaround 251. Which of the following is not true: The radar cross section of a target a) depends on the frequency used b) may be reduced by special coating of the target c) depends on the aspect of a target, if this non- spherical d) is equal to the actual cross-sectional area for small targets 252. It is a general term applied to the reduction in signal strength at the input to a receiver a) fading b) attenuation c) absorption d) ghosting 253. Indicate which of the following cannot be followed by the word “waveguide” a) elliptical b) flexible c) coaxial d) ridged 254. If the ratio of the antenna diameter to the wavelength in a radar system is high, this will result in (indicate the false statement) a) large maximum range b) good target discrimination c) difficult target acquisition d) increased capture area 255. High-power TWTs are replacing what in microwave amplifiers? a) MESFETs
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b) Magnetrons c) Klystrons d) IMPATT diodes 256. The most widely used microwave antenna is a a) half-wave dipole b) quarter-wave probe c) single loop d) horn 257. Applies to propagation variables in the physical radio path which affect changes in path loss between the transmitter at one station and its normal receiver at the other station. a) ghosting b) absorption c) attenuation d) fading 258. If the antenna diameter in a radar system is increased by a factor of 4, the maximum range will be increased by a factor of a) square root of 2 b) 2 c) 4 d) 8 259. If the peak transmitted power in a radar system is increased by a factor of 15, the maximum range will be increased by a factor of a) 2 b) 4 c) 8 d) 16 260. Varactor and step-recovery diodes are widely used in what type of circuit? a) amplifier b) oscillator c) frequency multiplier d) mixer 261. It is defined as line loss incurred by an electromagnetic wave as it propagates in a straight line through a vacuum with no absorption or reflection of energy from nearby objects. a) IRL b) FSL c) RSL d) Eb/No 262. For proper operation, a magnetron must be accompanied by a a) cavity resonator b) strong electric field c) permanent magnet d) high dc voltage 263. A police radar speed trap functions at a frequency of 1.024 GHz in direct line with your car. The reflected energy from your car is shifted 275 Hz in frequency. Calculate the speed in miles per hour? a) 60 mph b) 70 mph c) 80 mph d) 90 mph 264. It is the ratio of the wideband carrier to the wideband noise power a) carrier to noise ratio b) signal to noise ratio c) energy per bit per noise density ratio d) noise figure 265. What is the duty cycle of a radar pulse if the pulse width is 1μs, the pulse repetition rate is 900, and the average power is 18 W?
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