Analog Communication MCQ

Analog Communication MCQ. These 100 Multiple Choice Questions on “Analog Communication” will help you score full marks in your engineering exam.

Introduction to Analog Communication

What is Analog Communication?

Question 1: Which of the following best describes an analog signal?

A. A continuous signal that varies smoothly over time.

B. A discrete signal with distinct steps or levels.

C. A signal that can only take on two values.

D. A signal that uses binary code to represent information.

Question 2: What is a key advantage of analog communication?

A. High noise immunity.

B. Simple implementation.

C. Efficient use of bandwidth.

D. Secure transmission of data.

Question 3: What is a major disadvantage of analog communication?

A. Susceptibility to noise and distortion.

B. Low data transmission rates.

C. Difficulty in signal processing.

D. Incompatibility with modern technology.

Question 4: Which of the following is an example of analog communication?

A. Landline telephone.

B. Digital television.

C. Wi-Fi network.

D. Computer data transfer.

Question 5: How does analog communication differ from digital communication?

A. Analog uses continuous signals, while digital uses discrete signals.

B. Analog is more reliable than digital.

C. Analog is more efficient in terms of bandwidth usage.

D. Analog is better suited for long-distance communication.

Elements of a Communication System

Question 6: Which of the following is NOT a basic element of a communication system?

A. Transmitter.

B. Amplifier.

C. Channel.

D. Receiver.

Question 7: What is the function of a transmitter in a communication system?

A. To convert the information signal into a suitable form for transmission.

B. To receive and decode the transmitted signal.

C. To provide a pathway for signal propagation.

D. To interpret the received information.

Question 8: Which of the following is an example of a wireless communication channel?

A. Coaxial cable.

B. Optical fiber.

C. Radio waves.

D. Twisted pair cable.

Question 9: What is the purpose of modulation in a communication system?

A. To amplify the signal strength.

B. To remove noise from the signal.

C. To combine the information signal with a carrier wave.

D. To convert the signal from analog to digital.

Question 10: Which process is the reverse of modulation?

A. Amplification.

B. Demodulation.

C. Filtering.

D. Encoding.

Question 11: What is the role of the receiver in a communication system?

A. To generate the information signal.

B. To transmit the signal over the channel.

C. To extract the information from the received signal.

D. To amplify the received signal.

Question 12: What is the destination in a communication system?

A. The final point where the information is delivered.

B. The path through which the signal travels.

C. The device that encodes the information.

D. The device that amplifies the signal.

Question 13: Which of the following is an example of a wired communication channel?

A. Satellite link.

B. Cellular network.

C. Telephone line.

D. Bluetooth connection.

Question 14: What does signal filtering accomplish?

A. It increases the signal strength.

B. It removes unwanted frequencies from the signal.

C. It combines the signal with a carrier wave.

D. It converts the signal from analog to digital.

Question 15:  Which of the following is NOT a basic signal processing operation?

A. Modulation.

B. Quantization.

C. Filtering.

D. Amplification.

Signal Representation

Question 16:  What does the time-domain representation of a signal show?

A. The signal’s amplitude as a function of frequency.

B. The signal’s phase as a function of time.

C. The signal’s amplitude as a function of time.

D. The signal’s frequency as a function of amplitude.

Question 17: What does the frequency-domain representation of a signal show?

A. The signal’s amplitude at different frequencies.

B. The signal’s phase as a function of time.

C. The signal’s amplitude as a function of time.

D. The signal’s frequency as a function of amplitude.

Question 18: What is the Fourier transform used for?

A. Converting a time-domain signal to the frequency domain.

B. Amplifying the signal strength.

C. Removing noise from the signal.

D. Modulating the signal.

Question 19: What is the bandwidth of a signal?

A. The range of frequencies it occupies.

B. The highest frequency component in the signal.

C. The lowest frequency component in the signal.

D. The average amplitude of the signal.

Question 20: What is a periodic signal?

A. A signal that repeats itself over time.

B. A signal that does not repeat itself.

C. A signal with a random pattern.

D. A signal with a constant amplitude.

Question 21: What is an aperiodic signal?

A. A signal that repeats itself over time.

B. A signal that does not repeat itself.

C. A signal with a random pattern.

D. A signal with a constant amplitude.

Question 22:  What characterizes a deterministic signal?

A.  It cannot be predicted.

B. It has a random pattern.

C. Its future values can be predicted from its past values.

D. It has a constant frequency.

Question 23: Which of the following is an example of a random signal?

A. A sine wave.

B. A square wave.

C. Noise.

D. A DC voltage.

Question 24: What does the Fourier series represent?

A.  The frequency domain of an aperiodic signal.

B. The time domain of a random signal.

C.  The frequency components of a periodic signal.

D. The average amplitude of a signal.

Question 25: What is the spectrum of a signal?

A.  The range of amplitudes it can have.

B. The time it takes for the signal to complete one cycle.

C. The representation of the signal in the frequency domain.

D. The average power of the signal.

Amplitude Modulation (AM): Analog Communication MCQ

Introduction to AM

Question 26:  What is amplitude modulation (AM)?

A.  A method of encoding information by varying the frequency of a carrier wave.

B. A method of encoding information by varying the phase of a carrier wave.

C. A method of encoding information by varying the amplitude of a carrier wave.

D. A method of encoding information by converting it to a digital signal.

Question 28: In AM, what happens when the modulation index exceeds 1?

A. The signal becomes over-modulated, causing distortion.

B. The signal becomes under-modulated, resulting in weak reception.

C. The signal’s bandwidth decreases.

D. The signal’s frequency changes.

Question 29: Which type of AM is the most bandwidth efficient?

A. DSB-FC (Double Sideband Full Carrier)

B. DSB-SC (Double Sideband Suppressed Carrier)

C. SSB (Single Sideband)

D. VSB (Vestigial Sideband)

Question 30: Which type of AM is commonly used in AM radio broadcasting?

A. DSB-FC (Double Sideband Full Carrier)

B. DSB-SC (Double Sideband Suppressed Carrier)

C. SSB (Single Sideband)

D. VSB (Vestigial Sideband)

Question 31: What is the main advantage of DSB-SC over DSB-FC?

A.  Improved audio quality.

B. Reduced bandwidth.

C. Increased power efficiency.

D. Simpler demodulation.

Question 32: Why is VSB (Vestigial Sideband) used in television broadcasting?

A. To improve audio quality.

B. To reduce the bandwidth while preserving important low-frequency information.

C. To increase power efficiency.

D. To simplify demodulation.

Question 33: How are AM signals represented in the frequency domain?

A. As a single frequency.

B. As a pair of sidebands around the carrier frequency.

C. As a continuous spectrum of frequencies.

D. As a series of pulses.

Question 34: What is the purpose of the carrier wave in AM?

A. To carry the audio information.

B. To provide a frequency for the receiver to tune to.

C. To amplify the signal.

D. To filter out noise.

Question 35: What is the relationship between the message signal frequency and the sideband frequencies in AM?

A. The sidebands are at the same frequency as the message signal.

B. The sidebands are at twice the frequency of the message signal.

C. The sidebands are at the sum and difference frequencies of the carrier and message signals.

D. There is no relationship between the frequencies.

Generation of AM Signals

Question 36: Which device is commonly used for generating AM signals?

A.  Oscillator.

B.  Amplifier.

C.  Modulator.

D.  Demodulator.

Question 37: What is the function of a balanced modulator?

A. To generate a DSB-FC AM signal.

B. To generate a DSB-SC AM signal.

C. To demodulate an AM signal.

D. To amplify an AM signal.

Question 38:  Which component in a transistor modulator is responsible for varying the gain of the amplifier according to the message signal?

A.  Collector.

B.  Base.

C.  Emitter.

D.  Diode.

Question 39:  Why are balanced modulators preferred for generating DSB-SC signals?

A. They are simpler to implement.

B. They produce higher output power.

C. They effectively suppress the carrier wave.

D. They require less filtering.

Question 40: What is the role of the local oscillator in a modulator circuit?

A. To generate the audio signal.

B. To generate the carrier wave.

C. To amplify the modulated signal.

D. To demodulate the signal.

Demodulation of AM Signals

Question 41: What is the purpose of an envelope detector?

A. To generate an AM signal.

B. To demodulate an AM signal.

C. To amplify an AM signal.

D. To filter an AM signal.

Question 42: Which type of AM demodulator requires a locally generated carrier signal?

A. Envelope detector.

B. Synchronous detector.

C. Both envelope and synchronous detectors.

D. Neither envelope nor synchronous detectors.

Question 43: What is the main advantage of a synchronous detector over an envelope detector?

A. Simplicity.

B. Lower cost.

C. Improved noise performance.

D. Wider bandwidth.

Question 44: What component in an envelope detector is responsible for rectifying the AM signal?

A. Capacitor.

B. Resistor.

C. Diode.

D. Inductor.

Question 45: What is the function of the capacitor in an envelope detector?

A. To amplify the signal.

B. To filter out high-frequency components.

C. To generate the carrier wave.

D. To rectify the signal.

Applications of AM

Question 46: Which of the following is a common application of AM?

A. FM radio broadcasting.

B. Satellite television.

C. Mobile phone communication.

D. AM radio broadcasting.

Question 47: Why is AM suitable for two-way radio communication?

A. It provides high fidelity audio.

B. It is highly resistant to noise.

C. It is relatively simple and inexpensive to implement.

D. It uses a narrow bandwidth.

Question 48:  In aviation communication, what type of AM is often used for long-range communication?

A. DSB-FC.

B. SSB.

C. VSB.

D.  None of the above.

Question 49:  What is a disadvantage of using AM for broadcasting?

A. Limited range.

B. Poor audio quality compared to FM.

C. High power consumption.

D. Complex receiver design.

Question 50: What is an advantage of using AM for broadcasting?

A.  Wider bandwidth than FM.

B.  Simpler receiver design compared to FM.

C.  Higher noise immunity than FM.

D.  Better suited for stereo audio.

Angle Modulation: Analog Communication MCQ

Introduction to Angle Modulation

Question 51: What is the principle behind angle modulation?

A. Varying the amplitude of the carrier wave.

B. Varying the frequency or phase of the carrier wave according to the message signal.

C. Converting the analog signal to a digital signal.

D. Combining the message signal with a lower frequency carrier wave.

Question 52: Which of these is NOT a type of angle modulation?

A. Frequency Modulation (FM)

B. Phase Modulation (PM)

C. Amplitude Modulation (AM)

D. Both FM and PM

Question 53: In FM, what characteristic of the carrier wave is varied in accordance with the message signal?

A. Amplitude

B. Frequency

C. Phase

D. Both frequency and phase

Question 54: In PM, what characteristic of the carrier wave is varied?

A. Amplitude

B. Frequency

C. Phase

D. Both frequency and phase

Question 55: What is the modulation index in FM?

A. The ratio of the carrier frequency deviation to the message signal frequency.

B. The ratio of the message signal amplitude to the carrier wave amplitude.

C. The peak frequency deviation of the carrier wave.

D. The bandwidth of the modulated signal.

Question 56: How does the modulation index affect the bandwidth of an FM signal?

A. Higher modulation index leads to narrower bandwidth.

B. Higher modulation index leads to wider bandwidth.

C. Modulation index has no effect on bandwidth.

D. The relationship depends on the carrier frequency.

Question 57: What is a key advantage of FM over AM?

A. Simpler demodulation.

B. Lower bandwidth requirements.

C. Improved noise immunity.

D. Lower power consumption.

Question 58:  What is a disadvantage of FM compared to AM?

A.  Higher complexity.

B.  Lower audio fidelity.

C.  Increased susceptibility to noise.

D.  Shorter transmission range.

Question 59:  How is the message signal recovered in angle modulation?

A. By detecting the changes in the carrier wave’s amplitude.

B. By detecting the changes in the carrier wave’s frequency or phase.

C. By filtering out the carrier wave.

D. By converting the signal back to digital form.

Question 60: What mathematical function is often used to represent FM and PM signals?

A. Sine wave.

B. Square wave.

C. Bessel function.

D. Exponential function.

Generation of FM and PM Signals

Question 61: What are the two main methods for generating FM signals?

A. Direct FM and Indirect FM

B.  AM modulation and FM demodulation

C.  Envelope detection and Synchronous detection

D.  DSB-SC and SSB

Question 62:  In direct FM generation, how is the carrier frequency varied?

A. By using a voltage-controlled oscillator (VCO).

B. By using a phase modulator.

C. By using an envelope detector.

D. By using a frequency multiplier.

Question 63: What is the role of the phase modulator in indirect FM generation?

A. To directly vary the carrier frequency.

B. To generate a PM signal that is then converted to FM.

C. To demodulate the FM signal.

D. To amplify the FM signal.

Question 64: What is the purpose of a frequency multiplier in FM generation?

A. To increase the amplitude of the FM signal.

B. To increase the frequency deviation of the FM signal.

C. To demodulate the FM signal.

D. To filter out unwanted frequencies.

Question 65:  Which method of FM generation is generally simpler to implement for low modulation indices?

A. Direct FM.

B. Indirect FM.

C. Both are equally simple.

D.  Neither is suitable for low modulation indices.

Demodulation of FM and PM Signals

Question 66: What is the function of a slope detector in FM demodulation?

A. To convert frequency variations into amplitude variations.

B. To generate a carrier signal synchronized with the incoming FM signal.

C. To amplify the FM signal.

D. To filter out noise from the FM signal.

Question 67: What is a phase-locked loop (PLL)?

A. A circuit that generates an FM signal.

B. A circuit that demodulates an FM signal by locking onto the carrier frequency.

C. A circuit that amplifies an FM signal.

D. A circuit that filters an FM signal.

Question 68: What is the main advantage of using a PLL for FM demodulation?

A. Simplicity.

B. Low cost.

C. Improved noise performance.

D. Wider bandwidth.

Question 69: What component in a PLL is responsible for comparing the frequencies of the input signal and the VCO output?

A.  Phase detector.

B.  Low-pass filter.

C.  Voltage-controlled oscillator (VCO).

D.  Frequency multiplier.

Question 70: How does a PLL track changes in the frequency of the input FM signal?

A. By adjusting the gain of the amplifier.

B. By adjusting the cutoff frequency of the filter.

C. By adjusting the control voltage of the VCO.

D. By adjusting the modulation index.

Applications of Angle Modulation

Question 71: Which of the following is a common application of FM?

A. AM radio broadcasting.

B. Two-way radio communication.

C. FM radio broadcasting.

D. Landline telephone communication.

Question 72: Why is FM used in television broadcasting?

A. For transmitting the video signal.

B. For transmitting the audio signal.

C. For both video and audio signals.

D. For synchronizing the video and audio signals.

Question 73: What is an advantage of using FM in mobile communication?

A. Low power consumption.

B. Narrow bandwidth.

C. Resistance to fading and multipath interference.

D. Simple implementation.

Question 74: Why is FM suitable for satellite communication?

A. It is less susceptible to atmospheric noise.

B. It requires less power for long-distance transmission.

C. It allows for a large number of channels.

D. All of the above.

Question 75: What is a key difference between FM and PM in terms of their bandwidth requirements?

A. FM requires less bandwidth than PM.

B. FM requires more bandwidth than PM.

C.  FM and PM have the same bandwidth requirements.

D. The bandwidth depends on the carrier frequency.

Noise in Analog Communication: Analog Communication MCQ

Introduction to Noise

Question 76: What is noise in the context of analog communication?

A. Unwanted signals that interfere with the desired signal.

B.  The desired information signal.

C.  The carrier wave used for modulation.

D.  Distortion caused by over-modulation.

Question 77: Which of the following is NOT a common type of noise in communication systems?

A. Thermal noise.

B. Shot noise.

C. Quantization noise.

D. Flicker noise.

Question 78: What is the primary source of thermal noise?

A.  Lightning strikes.

B.  Solar flares.

C.  Random movement of electrons in conductors.

D.  Interference from other electronic devices.

Question 79: What is shot noise caused by?

A.  Random fluctuations in the number of electrons emitted from a cathode.

B.  Variations in the Earth’s magnetic field.

C.  Interference from power lines.

D.  Atmospheric disturbances.

Question 80: How does noise affect the quality of an analog signal?

A. It can introduce distortion and make the signal difficult to understand.

B. It can increase the signal strength.

C. It can reduce the bandwidth of the signal.

D. It has no effect on signal quality.

Signal-to-Noise Ratio (SNR)

Question 81: What does the signal-to-noise ratio (SNR) measure?

A. The relative strength of the desired signal compared to the noise.

B. The absolute power of the noise.

C. The bandwidth of the signal.

D. The frequency of the noise.

Question 82:  A higher SNR indicates:

A. A stronger noise signal.

B. A weaker desired signal.

C. A better quality signal.

D. A lower quality signal.

Question 83: What is noise figure?

A. The ratio of the input SNR to the output SNR of a device.

B. The absolute power of the noise at the input.

C. The temperature of the device.

D. The bandwidth of the device.

Question 84: What is the unit of SNR?

A. Watts.

B. Hertz.

C. Decibels (dB).

D. Volts.

Question 85: How is SNR calculated?

A. By dividing the noise power by the signal power.

B. By dividing the signal power by the noise power.

C. By adding the signal power and the noise power.

D. By subtracting the noise power from the signal power.

Noise Reduction Techniques

Question 86: Which of the following is NOT a technique for reducing noise in communication systems?

A. Filtering.

B. Shielding.

C. Amplification.

D. Grounding.

Question 87: How does shielding help reduce noise?

A. By blocking electromagnetic interference.

B. By amplifying the desired signal.

C. By grounding the system.

D. By filtering out unwanted frequencies.

Question 88: What is the purpose of grounding in noise reduction?

A. To provide a common reference point for voltages.

B. To amplify the desired signal.

C. To filter out unwanted frequencies.

D. To block electromagnetic interference.

Question 89: Why is FM generally more immune to noise than AM?

A.  FM uses a wider bandwidth.

B.  FM encodes information in the frequency variations, which are less affected by amplitude changes caused by noise.

C.  FM uses a higher carrier frequency.

D.  FM receivers are simpler.

Question 90: What is the purpose of error correction codes in communication systems?

A. To prevent noise from occurring.

B. To detect and correct errors caused by noise.

C. To amplify the signal.

D. To filter out noise.

Receivers: Analog Communication MCQ

Receiver Characteristics

Question 91: What does the sensitivity of a receiver indicate?

A. Its ability to reject unwanted signals.

B. Its ability to accurately reproduce the received signal.

C. Its ability to receive weak signals.

D. Its ability to handle a wide range of signal strengths.

Question 92: What is the selectivity of a receiver?

A. Its ability to select the desired signal from adjacent channels.

B. Its ability to amplify weak signals.

C. Its ability to handle strong signals without distortion.

D. Its ability to demodulate different types of modulation.

Question 93: What does the fidelity of a receiver refer to?

A. Its ability to reject unwanted signals.

B. Its ability to accurately reproduce the received signal.

C. Its ability to receive weak signals.

D. Its ability to handle a wide range of signal strengths.

Types of Receivers

Question 94: Which type of receiver uses multiple stages of RF amplification before demodulation?

A. Tuned radio frequency (TRF) receiver.

B. Superheterodyne receiver.

C. Direct conversion receiver.

D. All of the above.

Question 95: What is the main advantage of a superheterodyne receiver?

A. Simplicity.

B. High selectivity.

C. Low cost.

D. Wide bandwidth.

Question 96:  Which receiver type directly converts the RF signal to baseband?

A. TRF receiver.

B. Superheterodyne receiver.

C. Direct conversion receiver.

D. None of the above.

Receiver Circuits

Question 97: What is the function of the RF amplifier in a receiver?

A. To amplify the received signal at the radio frequency.

B. To mix the RF signal with the local oscillator signal.

C. To demodulate the signal.

D. To amplify the audio signal.

Question 98: What is the purpose of the mixer in a superheterodyne receiver?

A. To amplify the RF signal.

B. To convert the RF signal to an intermediate frequency (IF).

C. To demodulate the signal.

D. To filter out unwanted frequencies.

Question 99: What is the role of the local oscillator in a receiver?

A. To generate the audio signal.

B. To generate a signal that is mixed with the RF signal.

C. To amplify the modulated signal.

D. To demodulate the signal.

Question 100: What is the function of the IF amplifier in a superheterodyne receiver?

A. To amplify the received signal at the radio frequency.

B. To amplify the signal at the intermediate frequency.

C. To demodulate the signal.

D. To amplify the audio signal.

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