Noise in AM and Sampling Methods

In AM, the main type of noise affecting the signal is:

• Shot noise

• Thermal noise

• Atmospheric noise

• Flicker noise

The signal-to-noise ratio (SNR) in AM improves when:

• Modulation index is increased (up to 100%)

• Modulation index is decreased

• Bandwidth is increased

• Noise power is increased

Which type of noise is generated by random electron motion in resistors?

• Thermal noise

• Shot noise

• Transit-time noise

• Atmospheric noise

In AM receivers, noise affects:

• Only the carrier

• Only the sidebands

• Both carrier and sidebands

• Neither carrier nor sidebands

Thermal noise in resistors is caused by:

• Fluctuations in power supply

• Random motion of electrons due to temperature

• Electromagnetic interference from outside

• Poor grounding

Which type of internal noise is most dominant at low frequencies?

• Shot noise

• Flicker noise (1/f noise)

• Thermal noise

• Transit-time noise

Shot noise occurs due to:

• Mechanical vibrations in components

• Random emission of charge carriers across PN junctions

• External electromagnetic radiation

• Changes in ambient temperature

Transit-time noise becomes significant:

• At low voltages

• At high frequencies

• At room temperature

• In DC circuits only

Atmospheric noise is mainly caused by:

• Fluctuations in battery voltage

• Lightning and thunderstorms

• Solar radiation

• Switching transients

Which of the following is an example of extraterrestrial noise?

• Cosmic background radiation

• Industrial machinery interference

• Flicker noise

• Thermal noise