HIGHLIGHTED-Microwave-Communications.pdf

A inflight satellite system b terrestrial flight

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A. Inflight Satellite System B. Terrestrial Flight Telephone System C. World Airline Entertainment System D. Satellite Phone 147. ADF stands for A. Audio Direction Findings B . Automatic Direction Finder C. Alternate Direction Finder D. Automatic Distance Finder 148. RF carrier of the middle marker is modulated at ____ Hz. A. 1300 B. 1400 C. 1500 D. 1600 149. Which of the following is considered as the major advantage of using a helix traveling wave tube? A. Cheaper B. Less noise C. High power D. Wide bandwidth 150. RADAR stands for A. Radio Distance and Ranging B. Radio Detection and Ranging C. Radio Direction and Ranging D. Radio Distance and Range 151. Attenuator is used in the travelling wave tube to a. Help bunching b. Prevent oscillations c. Prevent saturation d. Increase gain 152. The multicavity klystron a. Is not a good low-level amplifier because of noise b. Has a high repeller voltage to ensure a rapid transmit time c. Is not suitable for pulsed operation d. Needs a long transit time through the buncher cavity to ensure current modulation 153. What is the effective radiated power of a repeater with 450 W transmitting power output, 4 dB feedline loss, 6dB duplexer loss, and 7 dB circulator and feedline loss and antenna gain of 25 dB? a. 2893.31 W b. 2523.83 W c. 2839.31 W d. 2425.38 W
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154. Magnetron oscillator are used for a. Generating SHF signals b. Multiplexing c. Generating rich harmonics d. FM demodulation 155. A microwave tube which has the advantage of having a high efficiency a. Cross-field amplifier b. Helix traveling wave tube c. Klystron d. Gridded tube 156. What term is used to describe the variation in a microwave oscillator frequency caused by power supply voltage or current changes? a. Frequency pulling b. Frequency pushing c. Post-tuning drift d. Tuning sensitivity 157. A rectangular waveguide has a width of 1.2 in and a height of 0.7 in. the waveguide will pass all signals above __ GHz. a. 4 GHz b. 8.44 GHz c. 10 GHz d. 4.92 GHz 158. Waveguides are a. A hollow tube that carries HF b. Solid conductors of RF c. Coaxial cables d. Copper wire 159. A TWT is sometimes preferred to the multi- cavity klystron amplifier because the former a. Is more efficient b. Has a greater bandwidth c. Has a higher number of modes d. Produces a higher output power 160. Variation in oscillator frequency with changes in load SWR a. Frequency pulling b. Frequency pushing c. Post-tuning drift d. Tuning sensitivity 161. It is the frequency change of an electronically tuned oscillator at a specified time after it has reached its desired frequency a. Frequency pulling b. Frequency pushing c. Post-tuning drift d. Tuning sensitivity 162. What is the power level of the smallest signal that can be detected above the noise by a Schottky diode?
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