HIGHLIGHTED-Microwave-Communications.pdf

The energy liberated form the collector 17 what is

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D. The energy liberated form the collector 17. What is the purpose of the electromagnetic field which surrounds a traveling-wave tube? A. To accelerate the electron B. To velocity modulate the electron beam C. To keep the electrons from spreading out D. To slow down the signal on the helix 18. Which of the following is used as an oscillator device in the SHF band? A. Thyratron tube B. Tunnel diode C. Klystron tube D. Both B and C 19. Microwave frequencies are normally regarded as those in the range of A. 1 to 500 MHz B. 1000 to 10,000 GHz C. 1 to 100 GHz D. 10 to 1000 GHz 20. The highest frequency which a conventional vacuum-tube oscillator can generate is not limited by the A. Electron transit time B. Distributed lead inductance C. Inter-electrode capacitance D. Degree of emission from the cathode 21. As the electron beam moves through a klystron’s intercavity drift space A. Frequency modulation at the input cavity creates velocity modulation at the output cavity B. Velocity modulation at the input cavity creates density modulation at the output cavity C. Density modulation at the input cavity creates velocity modulation at the output cavity D. Phase modulation at the input cavity creates velocity modulation at the output cavity. 22. The frequency of the oscillation generated by a magnetron, is mainly determined by A. The flux density of the external magnet B. The ratio of the dc cathode voltage to the magnetic flux density C. The number of the cavity resonators D. The dimension of each cavity resonator 23. If the instantaneous RF potentials on the two sides of a magnetron cavity are of opposite polarity, the operation is in the A. π mode B. π/2 mode
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C. 2π mode D. π/4 mode 24. The Gunn diode oscillator A. Is capable of generating continuous microwave power of the order of kilowatt B. Generates frequencies which are below 100 MHz C. Operates over a positive resistance characteristic D. Depends on the formation of charge domain 25. What ferrite device can be used instead of duplexer of isolate microwave transmitter and receiver when both are connected to the same antenna? A. Isolator B. Magnetron C. Simplex D. Circulator 26. To achieve good bearing resolution when using a pulsed-radar set, an important requirement is A. A narrow, antenna-beam width in the vertical plane B. A narrow, antenna-beam width in the horizontal plane C. A low repetition rate D. A high duty cycle 27. When used in conjunction with a radar set, the purpose of an echo box is to provide an artificial target. A. Which may be used to tune the radar synchronizer B. Which may be used to tune the radar receiver C. To the tone of the pulse repetition D. Tune the magnetron to the correct frequency 28. In a radar-set receiver, the usual mixer stage is A. And FET B. A tunnel diode C. A silicon crystal D. A Rochelle salts crystal 29. Klystron oscillators are most often used in the
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