How is aliasing prevented?

Aeronautical & Aerospace Engineering : Avionics - Quiz(MCQ)

Sampling at the same frequency of the original signal

Sampling at double the frequency of the original signal

Sampling at more than double the frequency of the original signal

Sampling at less than double the frequency of the original signal

Correct Answer : Sampling at more than double the frequency of the original signal

Explanation : Aliasing occurs when the sampling rate is lower than the frequency of the original signal. The Nyquist theorem states that the sampling rate should be more than twice the frequency of the original signal to avoid aliasing.

Recently Updated in Avionics Questions

Which one of the following is false with respect to fiber optic cables?

Costly

High speed

Less EM interference

Heavy compared to normal wires

Correct Answer : Option (D) : Heavy compared to normal wires

Explanation : Fiber optics weigh comparatively very low than normal wires. Wires require shielding from EMI which also adds up to the overall weight of the connectivity system. They also offer high speed data transfer and are relatively costly.

What type of multiplexing is used in optical fiber lines?

Time division multiplexing

wavelength division multiplexing

Code division multiplexing

Frequency division multiplexing

Correct Answer : Option (B) : wavelength division multiplexing

Explanation : Fibre optic data transmission use ‘wavelength division’ multiplexing whereby a single fibre can be used to transmit several channels of information as coded light pulses of different wavelengths (or colours) simultaneously. The individual data channels are then recovered from the optically mixed data by passing the light signal through wavelength selective passive optical filters which are tuned to the respective wavelengths. WDM has a very high integrity as the multiplexed channels are effectively optically isolated.

Where was the first Fly-By-Light system used?

Spacecrafts

Airships

Fighter aircraft

Bomber Aircraft

Correct Answer : Option (B) : Airships

Explanation : Non-rigid airships may be acquiring a new lease of life as long duration platforms for airborne radar surveillance systems. The airship is able to carry a large high power radar antenna within its envelope and is able to remain airborne for several days. Since the antenna could severely interfere with FBW systems FBL system was used.