ECE Refresher - EST

A linear diode detector uses RC filter. What will happen to the maximum permissible value of time constant RC as modulation index increases?

• remains constant

• increases

• decreases

• either increases or remains constant

The output noise power density of FM demodulator

• increases with frequency

• decreases with frequency

• remains unaltered

• none of these

Tags

NGSS.HS-PS4-1

Which of the following will be the resulting signal if an AM signal and a narrow band FM signal with identical carriers, modulating signals and modulation indices of 0.1 are mixed together?

• Broadband FM

• DSBSC

• SSB without carrier

• SSB with carrier

Tags

NGSS.HS-PS4-3

NGSS.HS-PS4-5

What is the generated modulation signal using filter method and phasing method?

• SSB signal

• vestigial side band signal

• both SSB and vestigial sideband signal

• none of these

Tags

NGSS.HS-PS4-5

In communication systems, what is the other name of modulating signal?

• base band signal

• side bands

• auxiliary signal

• none of these

Tags

NGSS.HS-PS4-5

In a wave, the electric field lines are vertical. Then, what type of polarization is the electromagnetic wave?

• horizontally polarized

• vertically polarized

• either horizontally or vertically polarized

• neither horizontally nor vertically polarized

Tags

NGSS.HS-PS4-5

Radar is used primarily to determine the range of the target. The maximum range of a radar is proportion to

• square root of peak transmitted pulse power

• 4th root of peak transmitted power

• peak transmitted pulse power

• none of these

In PCM system, if the quantization levels will increase from 2 to 8, what will happen to the relative bandwidth requirements?

• Get doubled

• Get tripled

• Remains the same

• become 8 times

The power transmitted of FM system will ____ if the depth of modulation is doubled.

• increase by factor of sqrt(2)

• increase by factor of sqrt(3)

• increase by factor of 2

• none of these

Tags

NGSS.HS-PS4-3

NGSS.HS-PS4-5

Which of the reasons why VSB modulation is preferred in TV?

• It reduces the bandwidth requirements to half

• it avoids phase distortion at low frequencies

• it results in better reception

• none of these

Tags

NGSS.HS-PS4-5