Objective Communications Questions – Electrical Engineering (Page 18)

#341📘 reviewer_appEasy

The three primary frequency bands are allocated by FCC for two-way FM radio communications except:

A132 MHz to 174 MHz

B450 MHz to 470 MHz

C806 MHz to 947 MHz

D1026 MHz to 1035 MHz

#342📘 reviewer_appMedium

The maximum frequency deviation for two-way transmitters is typically

A25 kHz

B5 kHz

C75 kHz

D3 kHz

#343📘 reviewer_appEasy

The maximum modulating signal frequency for two-way transmitter is typically

A3 kHz

B5 kHz

C15 kHz

D75 kHz

#344📘 reviewer_appEasy

The maximum deviation for narrowband FM?

A2500

B5

C1.67

D75

#345📘 reviewer_appEasy

Type of FM demodulator that is widely used in TV audio demodulators

ARatio detector

BQuadrature detector

CPLL

DPulse-averaging discriminator

#346📘 reviewer_appEasy

A variation of Foster-Seeley discriminator widely used in older TV receiver designs

ARatio detector

BPLL

CQuadrature detector

DCrosby modulator

#347📘 reviewer_appEasy

What is the maximum deviation for monoaural TV sound?

A25 kHz

B75 kHz

C50 kHz

D125 kHz

#348📘 reviewer_appEasy

What is the maximum deviation for stereo TV sound?

A25 kHz

B75 kHz

C50 kHz

D125 kHz

#349📘 reviewer_appEasy

In FM stereo broadcasting, the L + R signal

ADouble-sideband modulates a subcarrier

BModulates the FM carrier

CFrequency modulates a subcarrier

DIs not transmitted

#350📘 reviewer_appEasy

After the IF stages have been aligned, the next step to align in FM receiver is

Alocal oscillator

Blimiter stage

CRF amplifier

DMixer stage

#351📘 reviewer_appEasy

Under what conditions would a 1-kHz AF signal produce a signal pair of FM sidebands?

Awideband FM

Bbroadcast FM

CTV audio FM

Dnarrowband FM

#352📘 reviewer_appEasy

What deviation is considered 100% for FM broadcast stations?

A75 kHz

B220 kHz

C270 kHz

D75 kHz or 220 kHz

#353📘 reviewer_appEasy

What is the function of the dc that comes out of the dc amplifier in a PLL type FM detector?

Acarrier signal

Bfilter signal

Cerror signal or AF signal

Dphase signal

#354📘 reviewer_appEasy

Why should discriminators be tuned for a straight characteristic S-curve?

Aless AF distortion

Bgreater AF out

Cless RF out

Dless RF distortion

#355📘 reviewer_appEasy

In a Foster-Seeley and stagger-tuned discriminator, the AF output voltage is:

Avarying DC

Bvarying AC

Csteady AC

Dsteady DC

#356📘 reviewer_appEasy

In a ratio detector and gated-beam detector, the AF output voltage is:

Asteady AC

Bsteady DC

Cvarying DC

Dvarying AC

#357📘 reviewer_appEasy

Which of the ff discriminator circuits has its diodes in series?

Aratio

Bquadrature detector

Cround-travis detector

Dslope detector

#358📘 reviewer_appEasy

To what frequency must the gated-beam quadrature circuit be tuned in a TV receiver?

A10.7 MHz

B455 kHz

C70 MHz

D4.5 MHz

#359📘 reviewer_appEasy

In what way is the gated beam detector similar to the super regenerative detector?

APAM

BPCM

CPWM

DPPM

#360📘 reviewer_appEasy

With what FM detectors would AGC be an advantage?

Afoster-seeley detector

Bratio detector

Cquadrature detector

Dphase-locked loop

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