Description : In a multicavity klystron, tuning all the cavities to the same frequency has what effect on the bandwidth of the tube?
Last Answer : The bandwidth decreases.
Description : What limits the tuning range around the center frequency of a reflex klystron in a particular mode of operation?
Last Answer : The half-power points of the mode.
Description : Which of the following methods cannot be used to increase the bandwidth for cascaded RF amplifier stages? A) Wave traps in each stage B) Stagger tuning C) A shunt damping resistor across each tuned circuit D) Doubled tuned transformers with tighter coupling
Last Answer : A) Wave traps in each stage
Description : Retention for occlusal amalgam cavities in premolars is BEST provided by A. Slightly undercutting of walls with inversed cone bur B. Mesial and distal undercuts C. Buccal and lingual undercuts
Last Answer : C. Buccal and lingual undercuts
Description : A veena player compares with a tuning fork the fundamental frequency generated by one of the strings of the veena and hears 4 beats per second. He then tightens the string a bit and hears only 3 ... d) The string has a higher frequency than the fork and has to be loosened for equality with fork
Last Answer : Ans:(b)
Description : Beats phenomenon occurs when a vibrating system is subjected to two different frequencies which are A) Quite different B) Equal C) Slightly different D) Integral multiple of each other
Last Answer : C) Slightly different
Description : What type of klystron is used as the final stage of a power- amplifier transmitter?
Last Answer : Multicavity klystron.
Description : Debunching of the electron bunches in the higher modes of a reflex klystron has what effect on output power?
Last Answer : Power is reduced.
Description : If the constant-speed electrons in a reflex klystron remain in the repeller field for 1 3/4 cycles, what is the mode of operation?
Last Answer : Mode 2.
Description : The constant-speed electrons of an electron bunch in a reflex klystron must remain in the repeller field for what minimum time?
Last Answer : Three-quarter cycle.
Description : When the repealer potential is constant, what property of the electron determines how long it will remain in the drift space of the reflex klystron?
Last Answer : Velocity.
Description : What element of the reflex klystron replaces the output cavity of a normal klystron?
Last Answer : The reflector or repeller.
Description : Which cavity of a three-cavity klystron causes most of the velocity modulation?
Last Answer : The middle cavity.
Description : How is the electron beam of a three-cavity klystron accelerated toward the drift tube?
Last Answer : A large negative pulse is applied to the cathode.
Description : What can be added to the basic two-cavity klystron to increase the amount of velocity modulation and the power output?
Last Answer : Intermediate cavities between the input and output cavities.
Description : A two-cavity klystron without a feedback path will operate as what type of circuit?
Last Answer : Amplifier.
Description : The two-cavity klystron uses what cavity as an output cavity?
Last Answer : The catcher cavity.
Description : The electrons in the beam of a klystron are speeded up by a high dc potential applied to what elements?
Last Answer : The accelerator grid and the buncher grids.
Description : What is the basic principle of operation of a klystron?
Last Answer : Velocity modulation
Description : What should you do if a klystron becomes gassy?
Last Answer : Restore it to serviceable condition by operating it temporarily at reduced beam voltage.
Description : Without strapping, the resonant cavities of a hole-and-slot anode are connected in what manner?
Last Answer : Series.
Description : A cylindrical copper block with resonant cavities around the circumference is used as what component of a magnetron?
Last Answer : Anode or plate
Description : How many tuned parallel LC circuits are shown in this schematic?
Last Answer : Four.
Description : Inductive tuning of a resonant cavity is accomplished by placing a nonmagnetic slug in what area?
Last Answer : The area of maximum H lines.
Description : What is the primary measurement application for tuning forks?
Last Answer : They are used to monitor fixed motor speeds.
Description : Capacitive tuning by inserting a ring into the cavity slot of a magnetron is accomplished by what type of tuning mechanism?
Last Answer : . A cookie-cutter tuner
Description : Magnetron tuning by altering the surface-to-volume ratio of the hole portion of a hole-and-slot cavity is what type of tuning?
Last Answer : Inductive.
Description : What type of tuning does the receiver use?
Last Answer : Digital
Description : What are the tuning modes for the coupler group discussed?
Last Answer : Automatic, semiautomatic, and manual.
Description : What is the device called that will separate alternating current from direct current, or that will separate alternating current of one frequency from other alternating currents of different frequencies?
Last Answer : A filter.
Description : What type of insulator works well at very high frequencies?
Last Answer : A shorted quarter-wave section called a metallic insulator.
Description : At very high frequencies, what characteristics are displayed by ordinary insulators?
Last Answer : The characteristics of the dielectric of a capacitor.
Description : . Why are coaxial lines more efficient at microwave frequencies than two-wire transmission lines?
Last Answer : The electromagnetic fields are completely confined
Description : A cavity that vibrates at its natural frequency produces a louder sound than at other frequencies. What term is used to describe this phenomenon?
Last Answer : Resonance.
Description : What type filter is used to block the passage of current for a narrow band of frequencies, while allowing current to flow at all frequencies above or below this band?
Last Answer : . Band-reject.
Description : What type filter is used to allow a narrow band of frequencies to pass through a circuit and attenuate all other frequencies above or below the desired band?
Last Answer : Bandpass.
Description : What term is used to describe the frequency at which the filter circuit changes from the point of rejecting the unwanted frequencies to the point of passing the desired frequencies?
Last Answer : Frequency cutoff (fco).
Description : What is the filter called that passes low frequencies but rejects or attenuates high frequencies?
Last Answer : Low-pass filter, high-frequency discriminator or high-frequency attenuator.
Description : What is the filter called in which the low frequencies do not produce a useful voltage?
Last Answer : High-pass filter, low-frequency discriminator, or low-frequency attenuator.
Description : What is the band of frequencies called that is included between the two points at which current falls to 70 percent of its maximum value in a resonant circuit?
Last Answer : Bandwidth of the circuit
Description : What effect does transit time have on a conventional triode operated at uhf frequencies?
Last Answer : It causes the control grid to short to the cathode
Description : How does fog affect radio waves at frequencies above 2 gigahertz?
Last Answer : It can cause attenuation by absorbtion.
Description : When a wide band of frequencies is transmitted simultaneously, each frequency will vary in the amount of fading. What is this variable fading called?
Last Answer : Selective fading.
Description : Receiver bandwidth is defined as those frequencies spread between what two points of the receiver response curve?
Last Answer : Half-power points.
Description : What IF frequencies are normally used in radar receivers
Last Answer : Thirty or sixty megahertz.
Description : What transmitter component allows the radiation of a large number of discrete frequencies over a wide band?
Last Answer : . Frequency synthesizer.
Description : Why do 2D air-search radars use relatively low carrier frequencies and low pulse-repetition rates?
Last Answer : Increased maximum range.
Description : Is it possible for a transmission line to operate improperly at certain frequencies and properly at others?
Last Answer : Yes, it is quite common.
Description : What device sweeps a band of frequencies to determine frequencies and amplitudes of each frequency component?
Last Answer : Spectrum analyzer.