Receivers MCQs

Practice Receivers MCQs with four options, answers and explanations for focused Electronics & Telecommunication Engineering revision.

Question 1

Communication SystemsReceivers

A superheterodyne receiver converts a selected incoming RF signal to a fixed?

AAudio frequency only
BIntermediate frequency
CZero frequency in every receiver
DSampling frequency

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Correct Answer: B. Intermediate frequency

Explanation: A superheterodyne receiver mixes the selected RF signal with a local oscillator to produce a fixed intermediate frequency for convenient filtering and amplification.

Reference: Standard communication systems: receivers

Question 2

Communication SystemsReceivers

In a superheterodyne receiver, the intermediate frequency is produced by a?

AMixer
BPower amplifier only
CEnvelope capacitor only
DAntenna reflector

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Correct Answer: A. Mixer

Explanation: The mixer combines the RF input and local-oscillator signal, producing sum and difference frequency components; one is selected as the IF.

Reference: Standard communication systems: receivers

Question 3

Communication SystemsReceivers

A receiver is tuned to 1 MHz and uses a 455 kHz IF with high-side local-oscillator injection. The local oscillator frequency is?

A455 kHz
B545 kHz
C1.455 MHz
D2.455 MHz

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Correct Answer: C. 1.455 MHz

Explanation: For high-side injection, fLO=fRF+fIF=1.000+0.455=1.455 MHz.

Reference: Standard communication systems: receivers

Question 4

Communication SystemsReceivers

For a superheterodyne receiver using high-side injection, the image frequency is separated from the desired RF frequency by?

AfIF/2
BfIF
C2fIF
D4fIF

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Correct Answer: C. 2fIF

Explanation: With high-side injection, the image lies at fRF+2fIF, so its separation from the desired station is 2fIF.

Reference: Standard communication systems: receivers

Question 5

Communication SystemsReceivers

A receiver tuned to 1 MHz with IF=455 kHz and high-side injection has an image frequency of?

A1.455 MHz
B1.910 MHz
C2.000 MHz
D2.455 MHz

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Correct Answer: B. 1.910 MHz

Explanation: fimage=fRF+2fIF=1.000+0.910=1.910 MHz.

Reference: Standard communication systems: receivers

Question 6

Communication SystemsReceivers

The main purpose of automatic gain control (AGC) in a receiver is to?

AMaintain a more nearly constant output level despite changes in received signal strength
BIncrease carrier frequency continuously
CEliminate the local oscillator
DCreate intentional aliasing

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Correct Answer: A. Maintain a more nearly constant output level despite changes in received signal strength

Explanation: AGC automatically varies receiver gain so large variations in received signal strength produce smaller variations in output level.

Reference: Standard communication systems: receivers

Question 7

Communication SystemsReceivers

In a superheterodyne receiver, increasing the intermediate frequency generally improves?

AImage-frequency rejection for a given RF selectivity
BAudio output power automatically
CModulation index of the transmitter
DSampling resolution

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Correct Answer: A. Image-frequency rejection for a given RF selectivity

Explanation: A higher IF increases image separation from the desired RF signal, which can make image rejection easier for a given RF front-end selectivity.

Reference: Standard communication systems: IF trade-off

Question 8

Communication SystemsReceivers

In a superheterodyne receiver, using a lower intermediate frequency generally makes it easier to obtain?

ABetter adjacent-channel selectivity
BLarger image separation
CHigher antenna gain
DHigher transmitted power

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Correct Answer: A. Better adjacent-channel selectivity

Explanation: A lower IF permits narrower practical IF filters and can improve selectivity, although it worsens image-frequency separation.

Reference: Standard communication systems: IF selectivity trade-off