In Rf tuning, what is the first local oscillator?

Aeronautical & Aerospace Engineering : Avionics - Quiz(MCQ)

Frequency synthesizer

Quartz oscillator

Electric oscillators

Magnetic oscillator

Correct Answer : Frequency synthesizer

Explanation : In RF tuning, the first local oscillator is made adjustable. Generally, a frequency synthesizer is used in this application. The frequency synthesizer generates a highly stable signal at selected frequency increments.

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Which frequency band is used for connecting the satellite system with the public switched telephone network?

Ka band

L band

C band

Ku band

Correct Answer : Option (A) : Ka band

Explanation : The satellites communicate with ground stations called gateways that connect the system to the public switched telephone network. The satellites also communicate among themselves. Both gateway and intersatellite communication takes place over Ka band frequencies.

What provides the sufficient drive to the final power amplifier?

Up converter

Power driver circuit

Operational amplifier

Intermediate-power amplifier

Correct Answer : Option (D) : Intermediate-power amplifier

Explanation : The power amplifier usually begins with an initial stage called the intermediate-power amplifier (IPA). This provides sufficient drive to the final high-power amplifier (HPA).

What is the number of satellites present in the Iridium system?

Correct Answer : Option (B) : 66

Explanation : The satellite systems use low-earth-orbit satellites to perform the relay services to the main telephone system or to make a connection directly between any two cellular telephones using the system. One of the oldest and most widely used is the Iridium system. It uses a constellation of 66 satellites in six polar orbits with 11 satellites per orbit 420 mi above the earth.