MCQ on Communication Systems

To accurately sample an analog signal with a maximum frequency of 5 kHz, what is the minimum sampling rate required?

• 2.5 kHz

• 5 kHz

• 10 kHz

• 20 kHz

Which of the following is a disadvantage of increasing the sampling rate significantly beyond the Nyquist rate?

• Improved signal quality

• Increased data storage and processing requirements

• Simplified anti-aliasing filter design

• Better time resolution of signal

Why is modulation essential when transmitting low-frequency signals such as voice?

• To eliminate quantization noise

• To allow efficient transmission and reduce antenna size

• To remove aliasing

• To reduce jitter

Using a higher carrier frequency in modulation helps reduce antenna size because:

• The signal strength increases with frequency

• Higher frequencies penetrate obstacles better

• Wavelength decreases, allowing smaller antennas

• It avoids intersymbol interference

Which of the following is an advantage of Differential Pulse Code Modulation (DPCM) over standard PCM?

• Lower compression efficiency

• Reduced bit rate due to predictive encoding

• Higher data redundancy

• Higher error propagation

Intersymbol Interference (ISI) primarily occurs due to:

• Incorrect modulation scheme

• Overlapping of symbols caused by multipath propagation

• Poor analog-to-digital conversion

• Low quantization resolution

Which of the following is a common cause of ISI in indoor wireless communication?

• High transmission power

• Multipath reflections from walls and objects

• Low sampling rate

• Antenna misalignment

Which of the following is a technique used to reduce ISI in digital communication?

• Pulse shaping with raised cosine filters

• Frequency multiplexing

• Equalization at the receiver

• Using large antennas

Why is a cyclic prefix added in systems like OFDM?

• To increase the bit rate

• To combat intersymbol interference caused by multipath

• To simplify modulation

• To reduce power consumption

If you want to improve communication system robustness without changing the hardware, which technique is most effective?

• Use PCM instead of DPCM

• Apply Orthogonal Frequency Division Multiplexing (OFDM)

• Increase transmission power

• Decrease sampling rate