14: Digital Communication
- Page ID
- 1000
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)- 14.1: Introduction to Digital Communication
- This page examines the design and communication of digital information within large systems, focusing on water tank level monitoring. It compares analog signals, like 4-20 mA, with digital methods, citing benefits such as less interference. The page covers digital switches, binary encoding for improved measurement resolution, and converting analog to digital signals.
- 14.2: Networks and Busses
- This page explores the interchangeability of "bus" and "network" in digital communications, detailing communication standards like Fieldbus and Profibus that facilitate device connectivity. A hypothetical example, "BogusBus," underscores the importance of adhering to specifications.
- 14.3: Data Flow
- This page covers different communication methods in bus and network designs. It explains simplex communication as a one-way flow of information from sender to receiver, illustrated by BogusBus. It contrasts this with duplex communication, which enables two-way communication and includes half-duplex (devices alternate sending) and full-duplex (simultaneous sending) methods, often achieved through dual channels or multiple-frequency carrier waves.
- 14.4: Electrical Signal Types
- This page explores parallel versus serial communication networks, exemplified by BogusBus. It highlights the ease of parallel transmission versus the sequential nature and complexities of serial communication, which can suffer from noise and distortion, especially over distances. Solutions such as differential signaling and Frequency Shift Keying (FSK) are presented to improve reliability for long-distance communication.
- 14.5: Optical Data Communication
- This page explores the pros and cons of using optical signals for digital information transmission compared to electrical signals. It covers the conversion process involving LEDs and photodiodes, and details optical fibers' structure for efficient light transmission. Key challenges include microbending and signal distortion, particularly in multimode fibers, which can cause pulse stretching.
- 14.6: Network Topology
- This page examines various network topologies including point-to-point, bus, star, and ring configurations. It emphasizes the straightforwardness of point-to-point connections, the convenience and challenges of bus topology, the enhanced speed and security of star topology reliant on gateways, and the reliability of ring topology despite installation limitations. The page notes that these topologies can be combined to create hybrid setups in real-world applications.
- 14.7: Network Protocols
- This page highlights the importance of standardized communication protocols in preventing data corruption in networks, detailing the ISO DIS7498 model's seven layers of architecture and various protocol types, including CSMA and Token-Passing. It also describes a unique communication system where an HTD sends signals via twisted-pair cables to slave devices, categorizing them into initiators and responders.
- 14.8: Practical considerations - Digital Communication
- This page discusses the importance of guaranteed communication times in industrial control networks to ensure safety, such as in nuclear reactor operations. It contrasts deterministic networks, which assure data transfer times, with non-deterministic ones like Ethernet, prone to delays. The need for network fault tolerance is highlighted, as protocols like Master/Slave introduce single points of failure, while token-passing systems risk collisions with node failures.