Introduction to Electronics & Communication Engineering (Set-11)
What is wave propagation in the context of communication systems?
A Signal encoding
B Signal transmission through a medium
C Signal storage
D Signal amplification
Wave propagation refers to the process by which electromagnetic waves travel through different media (air, vacuum, etc.) to transfer information in communication systems. It is essential for transmitting radio waves, microwaves, and optical signals.
What does the term ‘RF’ stand for in communication systems?
A Range Frequency
B Reduced Frequency
C Radio Frequency
D Resistor Frequency
RF (Radio Frequency) refers to the range of frequencies used for transmitting signals in wireless communication systems, such as radio, television, and mobile phones. RF waves typically range from 3 kHz to 300 GHz.
Which of the following factors most affects the range of RF systems?
A Frequency
B Signal strength
C Voltage
D Temperature
The range of RF systems is significantly affected by frequency. Higher frequencies tend to have shorter ranges and are more susceptible to attenuation and interference, whereas lower frequencies can travel longer distances more effectively.
What type of noise is most commonly associated with communication systems?
A Shot noise
B External noise
C Quantum noise
D Thermal noise
Thermal noise, also known as Johnson Nyquist noise, arises due to the random thermal motion of electrons in conductors. It is inevitable and can affect the clarity and reliability of signals in communication systems.
What does the term ‘attenuation’ refer to in RF systems?
A Signal distortion
B Signal amplification
C Signal degradation with distance
D Signal reflection
Attenuation refers to the reduction in signal strength as it travels through a medium, primarily due to distance, absorption, and scattering. It is a key factor in the design of communication systems, especially in RF and optical communication.
What is the role of an RF filter in communication systems?
A Signal modulation
B Signal selection
C Signal amplification
D Signal attenuation
An RF filter allows specific frequencies to pass while blocking unwanted ones. It is crucial for selecting the desired frequency band and removing noise or interference in communication systems, ensuring clean signal transmission.
Which of the following factors does NOT contribute to noise in communication systems?
A Resistance
B Temperature
C Voltage
D Frequency
While temperature, resistance, and frequency all contribute to noise in communication systems, voltage itself does not directly cause noise. Noise typically arises from random electron motion, interference, and external sources in the system.
Which technique is commonly used to reduce the impact of noise in communication systems?
A Error correction coding
B Amplification
C Signal filtering
D Signal modulation
Error correction coding is used to detect and correct errors in transmitted data. It helps mitigate the effects of noise, improving the accuracy and reliability of the received signal, especially in digital communication systems.
What is the function of a dipole antenna?
A Generate radio waves
B Amplify signals
C Filter noise
D Transmit and receive signals
A dipole antenna is one of the simplest and most widely used antennas. It transmits and receives electromagnetic waves by converting electrical signals into radio waves and vice versa, facilitating wireless communication.
Which of the following is the primary cause of signal distortion in communication systems?
A Excessive signal power
B Frequency mismatch
C Reflection and refraction
D Signal attenuation
Reflection and refraction of signals cause distortion as they interfere with the direct path of transmission. These effects can lead to signal degradation, phase shifts, and interference, particularly in wireless communication over long distances.
What is the main advantage of using high frequency signals in communication systems?
A Lower power consumption
B Increased bandwidth
C Reduced interference
D Larger range
High frequency signals provide larger bandwidth, allowing more data to be transmitted over a given time. They are essential for high speed communication systems like 5G networks, satellite communication, and broadband wireless communication.
What is the purpose of using multiplexing in communication systems?
A Amplify signals
B Increase signal strength
C Transmit multiple signals over a single channel
D Reduce noise
Multiplexing allows multiple signals to be transmitted over a single communication channel by dividing the available bandwidth. This technique is used in telecommunication systems, such as frequency division multiplexing (FDM) and time division multiplexing (TDM).
Which type of wave is used in most RF communication systems?
A Square wave
B Triangle wave
C Electromagnetic wave
D Sine wave
Most RF communication systems use electromagnetic waves, which consist of oscillating electric and magnetic fields. These waves can travel through air, vacuum, and other media, enabling long distance wireless communication.
What is the primary limitation of wireless communication systems in terms of range?
A Power limitations
B Signal interference
C Frequency
D Bandwidth
The range of wireless communication systems is primarily limited by the power of the transmitted signal. Low power results in shorter range, while higher power increases the transmission range but can also cause interference and energy consumption issues.
Which of the following factors influences the speed and quality of signal propagation in wireless communication systems?
A Temperature
B Frequency
C Current
D Voltage
The frequency of the signal directly affects its speed and quality during propagation. Higher frequencies can carry more data but tend to have shorter range and are more affected by obstacles and environmental factors like rain or buildings.