Which of the following antennas is used for testing and adjusting a transmitter for proper modulation, amplifier operation and frequency accuracy? A. Elementary B. Real C. Isotropic D. Dummy

Which of the following antennas is used for testing and adjusting a transmitter for proper
modulation, amplifier operation and frequency accuracy?
A. Elementary
B. Real
C. Isotropic
D. Dummy
by

1 Answer

Answer :

D. Dummy
by

Related questions

It is useful to refer to an isotropic radiator. A. when comparing the gains of directional antennas B. when testing a transmission line for standing wave ratio C. when (in the northern hemisphere) directing the transmission D. when using a dummy load to tune a transmitter

Description : It is useful to refer to an isotropic radiator. A. when comparing the gains of directional antennas B. when testing a transmission line for standing wave ratio C. when (in the northern hemisphere) directing the transmission D. when using a dummy load to tune a transmitter

Last Answer : A. when comparing the gains of directional antennas

When is it useful to refer to an isotropic radiator? A. When comparing the gains of directional antennas B. When testing a transmission line for standing wave ratio C. When (in the northern hemisphere) directing the transmission in a southerly direction D. When using a dummy load to tune a transmitter

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Last Answer : A. When comparing the gains of directional antennas

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One of the following is a possible cause of an abrupt frequency variation in a self exited transmitter oscillator circuits resulting to a poor frequency stability to hold a constant frequency oscillation. A. Heating and expansion of oscillator coil B. DC and RF ac heating of resistors which cause change in values C. Heating of capacitor in the oscillatorD. Loose connections in the oscillator, amplifier, or antenna circuits.

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Which of the following is one of the possible causes for a slow drift of frequency in a self exited transmitter oscillator circuits resulting to a poor frequency stability? A. Poor soldered connections B. Power supply voltage changes C. Loose connections in the oscillator, amplifier, or antenna circuits D. DC and RF heating of resistors, causing then to change values.

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Description : A final amplifier of a radio transmitter draws 250 mA of plate current when the plate supply voltage is 1400 volts. If the plate circuit efficiency is 80% and the transmitter is connected to an antenna having a feed impedance of 70 ohms, ... at the feed-point? A. 4.0 A B. 2.2 A C. 1.25 A D. 2.0 A

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How can intermodulation interference between two transmitters in close proximity reduced or eliminated? A. Through installing a band-pass filter in the antenna feed line B. Through installing terminated circulator or ferrite isolator in the feed line of the transmitter and duplexer C. By using a class C final amplifier with high driving power D. By installing a low-pass filter in the antenna feed line

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The final power amplifier in an FM transmitter usually operates class ______. A. AB B. C C. B D. A

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The final amplifier of either FM or AM transmitter operates as A. Class B B. Class C C. Class A D. Class D

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What is meant by antenna gain? A. The final amplifier gain minus the transmission line losses (including any phasing lines present) B. The ratio of the amount of power produced by the antenna compared to the output power of the transmitter C. The ratio of the signal in the backward direction D. The numeric ratio relating the radiated signal strength of an antenna to that of another antenna

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Indicate the false statement. Noise figure is defined as A. the ratio of the S/N power supplied at the input terminal of a receiver or amplifier to the S/N power supplied to the output or load resistor B. noise factor expressed in decibels C. an unwanted form of energy tending to interfere with the proper and easy reception and reproduction of wanted signal D. S/N of an ideal system divided by S/N at the output of the receiver or amplifier under test, both working at the same temperature over the same bandwidth and fed from the same source

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Last Answer : A. Because their power is increased by class C amplifiers

What is the deviation ratio for an FM-phone signal having a maximum frequency swing of plus or minus 5 kHz and accepting a maximum modulation rate of 3kHz? A. 60 B. 0.16 C. 0.6 D. 1.66

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Last Answer : D. 1.66

What is the term used to describe a spread spectrum communications system where the center frequency if a conventional carrier is altered many time per second in accordance with a pseudo-random list of channels? A. Frequency hopping B. Direct sequence C. Time-domain frequency modulation D. Frequency compandored spread spectrum

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Last Answer : A. Frequency hopping

What is meant by the term modulation index? A. The processor index. B. The ratio between the deviation of a frequency modulated signal and the modulating frequency. C. The FM signal-to-noise ratio. D. The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency.

Description : What is meant by the term modulation index? A. The processor index. B. The ratio between the deviation of a frequency modulated signal and the modulating frequency. C. The FM signal-to-noise ratio. D. The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency.

Last Answer : B. The ratio between the deviation of a frequency modulated signal and the modulating frequency.

In modulation technique, which of the following is referred to audible pitch? A. Width B. Frequency C. Harmonic D. Amplitude

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Last Answer : B. Frequency

What is meant by the term deviation ratio? A. The ratio of the carrier center frequency to the audio modulating frequency B. The ratio of the highest audio modulating frequency to the average audio modulating frequency C. The ratio of the maximum carrier frequency deviation to the highest audio modulation frequency D. The ratio of the audio modulating frequency to the center carrier frequency

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Last Answer : C. Dynamic instability

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Last Answer : B. Suppressed white noise

Which of the following systems is not used in radio detection and ranging? A. Frequency shift B. Frequency modulation C. Pulse radar D. Amplitude modulation

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Description : Emission on a frequency or frequencies immediately outside the necessary bandwidth which result from the modulation process except spurious emission. A. Radiation B. Noise C. Out of the band D. Interference

Last Answer : C. Out of the band

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Description : A good example of a pilot tone system used in commercial frequency modulation stations. A. FDM B. Time division C. Stereo multiplexing D. Frequency modulation

Last Answer : C. Stereo multiplexing

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