1. The main purpose of modulation in communication systems is to:
Answer:
Explanation:
Modulation is used in communication systems to modify a signal so it can be efficiently transmitted over long distances and through various media.
2. In frequency modulation (FM):
Answer:
Explanation:
In frequency modulation, the frequency of the carrier wave is varied in accordance with the amplitude of the input signal.
3. An advantage of digital communication over analog communication is:
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Explanation:
Digital communication systems offer better noise immunity and are more robust against signal degradation compared to analog systems.
4. The Shannon-Hartley theorem relates to:
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Explanation:
The Shannon-Hartley theorem provides a formula to determine the maximum data rate for a noisy communication channel, given its bandwidth and signal-to-noise ratio.
5. In a communication system, 'bandwidth' refers to:
Answer:
Explanation:
Bandwidth in communication systems refers to the range of frequencies that a transmission channel can carry.
6. Optical fiber communication primarily uses which type of signal for transmission?
Answer:
Explanation:
Optical fiber communication systems use light signals for transmission, typically in the form of laser or LED light.
7. What is the primary function of a repeater in communication systems?
Answer:
Explanation:
Repeaters are used in communication systems to amplify and regenerate signals, extending the range over which data can be transmitted.
8. MIMO technology in wireless communication stands for:
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Explanation:
MIMO (Multiple Input, Multiple Output) is a technology used in wireless communication that utilizes multiple antennas at both the transmitter and receiver to improve communication performance.
9. The primary disadvantage of amplitude modulation (AM) is:
Answer:
Explanation:
Amplitude modulation is more susceptible to noise and interference compared to other modulation techniques because the information is contained in the amplitude, which can be easily affected by noise.
10. In satellite communication, the 'uplink' refers to:
Answer:
Explanation:
In satellite communication, the uplink is the transmission path from the ground station up to the satellite.
11. CDMA stands for:
Answer:
Explanation:
CDMA (Code Division Multiple Access) is a channel access method used in various radio communication technologies, where multiple transmitters can send information simultaneously over a single communication channel.
12. The main purpose of a duplexer in communication systems is to:
Answer:
Explanation:
A duplexer is a device that allows a transmitter and receiver to use the same antenna simultaneously without interfering with each other.
13. Orthogonal Frequency-Division Multiplexing (OFDM) is used to:
Answer:
Explanation:
OFDM is a method of encoding digital data on multiple carrier frequencies, minimizing interference and crosstalk between the closely spaced frequencies.
14. The term 'attenuation' in communication systems refers to:
Answer:
Explanation:
Attenuation is the reduction in the strength of a signal as it propagates through a medium.
15. In a communication system, a 'transducer' is used to:
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Explanation:
A transducer is a device that converts one form of energy to another, such as a microphone converting sound energy into electrical signals.
16. The main advantage of using fiber optics for communication is:
Answer:
Explanation:
Fiber optics offer a much greater bandwidth compared to traditional copper cables, allowing for higher data transmission rates.
17. Line-of-sight communication is essential for:
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Explanation:
Line-of-sight communication is crucial for satellite communication, as the transmitting and receiving antennas need to be in direct view of each other without any obstacles.
18. In RF communication, 'RF' stands for:
Answer:
Explanation:
RF stands for Radio Frequency, referring to the rate of oscillation in the range of about 30 kHz to 300 GHz, which corresponds to the frequency of radio waves.
19. The main purpose of error detection and correction in communication systems is to:
Answer:
Explanation:
Error detection and correction techniques are used in communication systems to ensure the integrity of data being transmitted, especially over noisy channels.
20. The 'bit error rate' in digital communication is a measure of:
Answer:
Explanation:
The bit error rate is the number of bit errors divided by the total number of transferred bits during a studied time interval.
21. In a communication system, 'multiplexing' refers to:
Answer:
Explanation:
Multiplexing is the process of combining multiple signals into one signal over a shared medium, allowing for more efficient use of resources.
22. The term 'latency' in communication systems refers to:
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Explanation:
Latency in communication systems is the time delay experienced between the transmission and reception of a signal.
23. In a communication system, a 'parabolic antenna' is typically used for:
Answer:
Explanation:
Parabolic antennas, with their dish-like shape, are commonly used for satellite communication due to their high directivity and ability to focus signals to a narrow beam.
24. QAM in digital communication stands for:
Answer:
Explanation:
QAM (Quadrature Amplitude Modulation) is a modulation scheme that conveys data by changing the amplitude of two carrier waves, using amplitude-shift keying (ASK) or phase-shift keying (PSK).
25. The primary function of a satellite in communication systems is to:
Answer:
Explanation:
Satellites in communication systems act as relay stations that receive signals transmitted from the earth, amplify them, and retransmit them back to different locations on the earth.