Modulation and Demodulation MCQs

1.Why is the intermediate frequency (IF) in a superheterodyne receiver selected as the difference between the received and oscillator frequencies rather than their sum?

Because the difference frequency is nearer to the oscillator frequencySince lower frequencies are simpler to amplify effectivelyBecause only the difference frequency supports modulationNone of these reasons apply

2.In a TRF radio receiver, to which frequency are the RF and detection sections typically tuned?

Radio frequencyIntermediate frequencyAudio frequencyNo specific frequency

3.What is the power contained in the sidebands according to the previous question?

4.Which type of modulation is used for the audio signal in television broadcasting?

5.Where is the diode detector typically located in an AM radio receiver circuit?

Prior to the initial RF amplification stageImmediately following the first RF amplification stageSubsequent to multiple amplification stagesNot applicable to any of the above

6.What is the power contained in the sidebands according to the previous question?

7.What does modulation involve when a low-frequency signal influences a carrier wave?

Changing the carrier's amplitudeAltering the carrier's frequencyModifying the carrier's phaseAny of the above can be controlled

8.What is the primary benefit of Frequency Modulation (FM) compared to Amplitude Modulation (AM)?

It provides clearer reception with less noise interferenceIt operates at a higher carrier frequencyIt requires a narrower bandwidthIt involves minimal frequency deviation

9.What does the superheterodyne principle involve?

Employing multiple amplifier stagesImplementing a push-pull configurationGenerating a lower, fixed intermediate frequencyNone of these choices

10.At which stage does the superheterodyne technique achieve signal selectivity?

11.In a superheterodyne receiver, which stage is responsible for the majority of signal amplification?

12.What term describes a radio receiver that amplifies all incoming signal frequencies with equal effectiveness?

13.What does the abbreviation AVC represent?

Audio voltage regulationSudden voltage adjustmentAutomatic volume regulationAutomatic voltage adjustment

14.In a superheterodyne receiver, what signals are fed into the mixer stage?

Intermediate frequency and radio frequency signalsRadio frequency and audio frequency signalsIntermediate frequency and audio frequency signalsRadio frequency signal and local oscillator output

15.What type of modulation occurs when the frequency of the carrier wave is varied according to the modulating signal?

Modulation of phaseModulation of amplitudeModulation of frequencyCould be any of the listed types

16.Given an intermediate frequency (IF) of 455 kHz and a radio receiver tuned to 855 kHz, what is the frequency of the local oscillator?

17.What is the primary purpose of a ferrite antenna?

Minimize unwanted capacitanceMaintain a stable direct current biasEnhance the quality factor (Q) of a tuned circuitLower the level of noise interference

18.A carrier voltage of 100 V is modulated such that its amplitude fluctuates between 160 V and 40 V. What is the modulation index?

365None of these

19.Given Amin = 40 and Amax = 60, what is the modulation percentage?

20%40%50%10%

20.Which type of oscillator is commonly employed as the local oscillator in a radio receiver?

Crystal oscillatorWien-bridge oscillatorPhase-shift oscillatorHartley oscillator