EEC2500 Introduction To Elec. & Comm. Concepts Presentation PDF

EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System What is Communication System? FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 4  EEC2500 Introduction To Elec....

EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System What is Communication System? FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 4  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Communications Model [1/6] Data communication examines how data in the form of energy travel across some medium from a source to a destination. The fundamental purpose of a communications system is the exchange of data between two points. FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 17  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Communications Model [2/6] In a simplified communication system, the source (transmission) system plays a crucial role in transmitting information from the source (sender or transmitter) to the destination (receiver). The system involves the physical and logical components that enable the movement of data from one point to another. Here's an overview of the key components in a simplified communication system's transmission system: FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 18  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Communications Model [3/6] Source System: Device to transform/encode the signal generated by the source Source: Generates data to be transmitted. Transmitter: Converts data into transmittable signals. FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 19  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Communications Model [4/6] Transmission System: Medium that will allow transport of signal from one point to another. Examples: Copper cables, fiber optics, radio waves, or a combination of these. FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 20  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Communications Model [5/6] Destination System: Device to decode the received signal for handling by destination device Receiver: Converts received signal into data. Destination: Takes incoming data. FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 21  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Communications Model [6/6] The figure below, presents a communication between a workstation and a server over a public telephone network. Another example is the exchange of voice signals between two telephones over the same network. FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 22  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Next Lecture What allows different applications existence without interruption? FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 23  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Frequency Allocation and Spectrum Licensing Role of Regulatory Bodies in Frequency Allocation: Federal Communications Commission (FCC): In the United States, the FCC is responsible for managing and licensing the radio spectrum. It allocates specific bands for different applications (like Wi-Fi, cellular networks, emergency services, and broadcasting) to prevent interference (minimizing the chances of two services overlapping). International Telecommunication Union (ITU): The ITU, an agency of the United Nations, plays a global role in spectrum management. The ITU divides the world into three regions (Region 1: Europe, Africa, Russia; Region 2: Americas; Region 3: Asia and Oceania) and allocates spectrum differently in each, adapting to regional needs (It coordinates international agreements on frequency use ). FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 25  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Frequency Allocation and Spectrum Licensing Why Frequency Allocation and Licensing Matter? Prevents Interference: By allocating specific bands for each type of service, the chance of interference between services is significantly reduced. Supports Diverse Applications: Different applications, like emergency services, television broadcasting, and satellite communication, have unique requirements. Efficient Use of Limited Spectrum: The radio spectrum is finite, so allocating bands carefully allows multiple services to coexist without degrading the quality of any one service. FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 26  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Data (Signal) Transmission [1/4] The successful transmission of data depends principally on two factors: The quality of the signal being transmitted. The characteristics of the transmission medium. Data transmission occurs between a transmitter and a receiver over some transmission medium. Guided media (physical path) Twisted pair, coaxial cable, optical fiber Unguided (wireless) media Propagation through air, vacuum, and seawater FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 28  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Data (Signal) Transmission [2/4] FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 29  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Data (Signal) Transmission [3/4] The term direct link is used to refer to the transmission path between two devices in which signals propagate directly from transmitter to receiver with no intermediate devices (amplifiers or repeaters used to increase signal strength) Note that this term can apply to both guided and unguided media. A guided transmission medium is point to point if it provides a direct link between two devices and those are the only two devices sharing the medium. In a multipoint guided configuration, more than two devices share the same medium. FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 30  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Data (Signal) Transmission [4/4] A transmission may be simplex, half duplex, or full duplex. In simplex transmission, signals are transmitted in only one direction; one station is transmitter and the other is receiver. e.g. cable television In half-duplex operation, both stations may transmit, but only one at a time. e.g. police radio In full-duplex operation, both stations may transmit simultaneously. e.g. telephone FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 31 Operations on Signal 32  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Analog and Digital Data Transmission The terms analog and digital correspond, roughly, to continuous and discrete, respectively. Analog and digital concepts are applied to data, signals, and transmission. Data carry information while signals are electric or electromagnetic representations of data. Signaling is the physical propagation of the signal along a suitable medium whereas transmission involves the communication of data by the propagation and processing of signals. FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 33  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Analog and Digital Data Analog data take on continuous values in some interval, while digital data take on discrete values. Audio is the most familiar example of analog data, while text or character strings are a familiar example of digital data. Most data collected by sensors, such as temperature and pressure, are continuously valued. FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 34  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Analog and Digital Signals In a communications system, data are propagated from one point to another using electric or electromagnetic signals. An analog signal is a continuously varying electromagnetic wave that may be propagated over a variety of media, depending on the spectrum; examples are wire media, such as twisted pair and coaxial cable; fiber optic cable; and unguided media, such as atmosphere or space propagation. A digital signal is a sequence of voltage pulses that may be transmitted over a wire medium; The principal advantages of digital signaling are that it is generally cheaper than analog signaling and is less susceptible to noise interference. The principal disadvantage is that digital signals suffer more from attenuation than analog signals. FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 35  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Data And Signals [1/4] Analog signals, are used to represent analog data, and digital signals, are used to represent digital data. (or ……..) Generally, analog data are a function of time and occupy a limited frequency spectrum. Digital data can be represented by digital signals, with a different voltage level for each of the two binary digits. FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 36  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Data And Signals [2/4] (or ……..) As the last figure illustrates, these are not the only possibilities. Digital data can also be represented by analog signals by use of a modem (modulator/demodulator). The modem converts a series of binary (two-valued) voltage pulses into an analog signal by encoding the digital data onto a carrier frequency. FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 37  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Data And Signals [3/4] The resulting signal occupies a certain spectrum of frequency centered about the carrier and may be propagated across a medium suitable for that carrier. The most common modems represent digital data in the voice spectrum and hence allow those data to be propagated over ordinary voice-grade telephone lines. At the other end of the line, another modem demodulates the signal to recover the original data. FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 38  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Data And Signals [4/4] In an operation very similar to that performed by a modem, analog data can be represented by digital signals. The device that performs this function for voice data is a codec (coder- decoder). The codec takes an analog signal that directly represents the voice data and approximates that signal by a bit stream. At the receiving end, the bit stream is used to reconstruct the analog data. FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 39  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Transmission Impairments The signal received may differ from the signal transmitted causing: Degradation of signal quality (analog) Bit errors (digital) Most significant impairments are Attenuation (distortion) Delay distortion Noise FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 40  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Attenuation Signal strength falls off with distance over any communications medium Varies with frequency – higher has more Received signal strength must be: strong enough to be detected sufficiently higher than noise to be received without error Strength increased with repeaters or amplifiers FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 41  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Delay Distortion Delay distortion is a phenomenon that occurs in transmission cables (such as twisted pair, coaxial cable, and optical fiber) and also in satellite communication (approximately 240 milliseconds for satellite in geostationary orbit). FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 42  EEC2500 Introduction To Elec. & Comm. Concepts A simple Communication System Noise Unwanted signals that are inserted somewhere between transmission and reception Major limiting factor in communications system performance Crosstalk: A signal from one line is picked up by another FALL 2024-2025 Lecturers: Dr. Mohamed Shehata & Dr. Mohamed Atef Abbas 43