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Questions and Answers
What is the result of the Bit Error Rate (BER) calculation when there are 3 incorrect bits out of 10 transferred bits?
What is the result of the Bit Error Rate (BER) calculation when there are 3 incorrect bits out of 10 transferred bits?
Which factor does NOT affect the Bit Error Rate (BER) in a communication system?
Which factor does NOT affect the Bit Error Rate (BER) in a communication system?
What is one method to improve the Bit Error Rate (BER) mentioned in the content?
What is one method to improve the Bit Error Rate (BER) mentioned in the content?
Which technique is mentioned as effective for mitigating channel distortions and interference?
Which technique is mentioned as effective for mitigating channel distortions and interference?
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How does a strong signal strength affect BER?
How does a strong signal strength affect BER?
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Which of the following modulation schemes is known for providing higher data throughput?
Which of the following modulation schemes is known for providing higher data throughput?
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What is a key trade-off when achieving a lower Bit Error Rate (BER)?
What is a key trade-off when achieving a lower Bit Error Rate (BER)?
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Which channel coding technique is mentioned as a way to improve BER performance?
Which channel coding technique is mentioned as a way to improve BER performance?
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What is Intersymbol Interference (ISI)?
What is Intersymbol Interference (ISI)?
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Which of the following is NOT a cause of Intersymbol Interference?
Which of the following is NOT a cause of Intersymbol Interference?
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According to the Nyquist Criterion, what condition must be met for zero-ISI transmission?
According to the Nyquist Criterion, what condition must be met for zero-ISI transmission?
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In the context of ISI, what does multipath propagation refer to?
In the context of ISI, what does multipath propagation refer to?
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What is the time domain condition for the received pulse according to the Nyquist Criterion?
What is the time domain condition for the received pulse according to the Nyquist Criterion?
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The spreading of pulses in a channel can be caused by which of the following factors?
The spreading of pulses in a channel can be caused by which of the following factors?
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What is the primary purpose of bandwidth in a communication network?
What is the primary purpose of bandwidth in a communication network?
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Which mathematical form of the Nyquist Criterion is used to evaluate zero-ISI in frequency domain?
Which mathematical form of the Nyquist Criterion is used to evaluate zero-ISI in frequency domain?
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What happens to the bit duration ($T_b$) if pulse spreading occurs due to a bandlimited channel?
What happens to the bit duration ($T_b$) if pulse spreading occurs due to a bandlimited channel?
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How is bit error rate (BER) typically expressed?
How is bit error rate (BER) typically expressed?
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Which unit is NOT used to measure bit rate?
Which unit is NOT used to measure bit rate?
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What does a high bandwidth imply about a communication channel?
What does a high bandwidth imply about a communication channel?
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What contributes to bit errors in digital transmissions?
What contributes to bit errors in digital transmissions?
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In the context of data transmission, what does the term 'bit rate' refer to?
In the context of data transmission, what does the term 'bit rate' refer to?
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If a communication channel has a bandwidth of 100 Mbps, what does this imply?
If a communication channel has a bandwidth of 100 Mbps, what does this imply?
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What does a bit error rate (BER) of 3% signify in a data stream?
What does a bit error rate (BER) of 3% signify in a data stream?
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How does transmit power control contribute to improving BER?
How does transmit power control contribute to improving BER?
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What is the primary benefit of utilizing antenna diversity?
What is the primary benefit of utilizing antenna diversity?
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Which factor is NOT essential for achieving an improved BER according to a comprehensive system design?
Which factor is NOT essential for achieving an improved BER according to a comprehensive system design?
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Pulse Amplitude Modulation (PAM) represents binary digits by varying which component?
Pulse Amplitude Modulation (PAM) represents binary digits by varying which component?
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What role does the transmitting filter play in the PAM transmission system?
What role does the transmitting filter play in the PAM transmission system?
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What is one of the key challenges faced in the channel that affects signal quality?
What is one of the key challenges faced in the channel that affects signal quality?
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Which component is responsible for removing noise from a received signal in the PAM system?
Which component is responsible for removing noise from a received signal in the PAM system?
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What is the main focus of interference avoidance and management in communication systems?
What is the main focus of interference avoidance and management in communication systems?
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Study Notes
ECEN 90 - Communications 2 Study Notes
- Course title: ECEN 90 - Communications 2
- Instructor: Lemuel G. Tatad
- Learning Objectives: After completing the chapter, students will be able to connect the concepts of bandwidth, bit rate, bit error rate, power, and complexity.
Introduction of Terms
- Bit rate: The rate at which data is processed or transferred. Measured in units per second. Units include bps, Kbps, Mbps, and Gbps, with higher units representing higher bit rates. Also known as data rate.
- Data Transfer Rate (DTR): The amount of digital data transferred in a given time.
Bit Rate Table
- A table showing various bit rate units, their corresponding symbols, multiples, decimal equivalents, and binary equivalents.
Introduction of Terms (Bandwidth)
- Bandwidth: Similar to maximum bit rate in a communication network. It's the transferring capacity of a communication channel or medium. It represents the maximum rate bits can be transferred from a source to a destination.
- It also indicates the amount of time required for transmitting or receiving data over a network.
Bandwidth vs. Bitrate Table
- A table comparing bandwidth and bitrate, explicitly defining each term, outlining units of measurement and highlighting that bit rate is always less than or equal to bandwidth.
Introduction of Terms (Bit Error Rate - BER)
- Bit Error Rate (BER): The number of bit errors divided by the total number of transmitted bits during a specific time interval. BER is a unitless performance measure, often expressed as a percentage.
- Errors occur due to noise, interference, distortion, or bit synchronization errors during digital transmission.
Introduction of Terms (BER Examples)
- An example of BER calculation is provided using a transmitted bit sequence (0110001011) and a received sequence (001010101). The BER was calculated as 0.3 or 30%.
Introduction of Terms (Factors Affecting BER)
- Factors affecting BER include channel noise, interference, distortion, bit synchronization problems, attenuation, wireless multipath fading, etc.
Introduction of Terms (Improving BER)
- Methods to improve BER include optimizing transmit signal strength, selecting robust modulation/line coding scheme, implementing channel coding (e.g., forward error correction), employing equalization techniques to mitigate channel distortions, boosting signal strength through amplification and filtering, and reducing receiver noise.
Introduction of Terms (Baseband Binary PAM Transmission System Model)
- PAM (Pulse Amplitude Modulation): A method of transmitting digital data by varying the amplitude of discrete pulses.
- Binary PAM system uses two amplitudes to represent binary digits (0 and 1).
- PAM is efficient in terms of power and bandwidth utilization
System Components (Transmitter, Channel, Receiver)
- Detailed breakdown of the transmitter components (input sequence, pulse generator, transmitting filter)
- Breakdown of the channel (medium through which the signal is transmitted, often affected by noise)
- Breakdown of the receiver components (receiving filter, decision device)
- A diagram illustrating the components and their interactions in a Baseband binary PAM transmission system.
Intersymbol Interference (ISI)
- Intersymbol Interference (ISI): Occurs when a pulse spreads out to interfere with adjacent pulses at a sample instant.
- Causes of ISI include channel distortion, multipath propagation (wireless signals taking different paths), and bandwidth limitations.
- An example using polar NRZ (non-return to zero) line code, demonstrating how bandwidth limitations can spread (smear) pulses
Intersymbol Interference (ISI) - Nyquist Criterion
- Nyquist Criterion (Zero-ISI Transmission): A condition where pulses have no ISI when transmitted through a channel with sufficient bandwidth.
- A concise summary of the time domain and frequency domain conditions for eliminating ISI in a communication system
- Raised cosine-rolloff Nyquist filter is a solution that controls bandwidth to effectively minimize ISI.
- Nyquist Criterion difficulties with overall amplitude transfer characteristics being unrealistic and synchronization issues.
Intersymbol Interference (ISI) - Eye Diagram
- Eye Diagram: A graphical representation showing the degradation of signal quality during communication.
- How eye diagram width, optimum sampling time, and height of the opening are analyzed to determine the margin of signal quality over channel noise.
Optimum System Design for Noise Immunity
- The major objectives in designing for noise immunity are to carefully choose appropriate transmitting (HT(f)) and receiving (HR(f)) filters to minimize ISI in non-ideal communication channel, transmit pulse (G(f)), receive pulse(H(f)), in order to obtain the minimum achievable BER.
Optimum System Design for Noise Immunity (Assumptions)
- Practical significance includes ensuring input bits to a pulse generator are independent and equiprobable
- The transmit pulse (G(f)) is sufficiently narrow with respect to its Fourier transform that it does not change considerably across the relevant frequency bandwidth in question.
- Noise is additive white Gaussian noise(AWGN) with a specified power spectral density of N0/2
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Description
This quiz covers key concepts from the ECEN 90 Communications 2 course, focusing on important topics such as bit rate, bandwidth, and data transfer rates. Students will learn to connect these concepts effectively. Test your understanding and prepare for upcoming exams with this comprehensive overview.
