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Overview of Electrical Engineering

Overview of Electrical Engineering. Lecture 8A: Introduction to Engineering. Foundations of Electrical Engineering. Electrophysics Information (Communications) Theory Digital Logic. Foundations of Electrical Engineering. Electrophysics :

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Overview of Electrical Engineering

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  1. Overview of Electrical Engineering Lecture 8A: Introduction to Engineering 1

  2. Foundations of Electrical Engineering • Electrophysics • Information (Communications) Theory • Digital Logic 2

  3. Foundations of Electrical Engineering • Electrophysics: • Fundamental theories of physics and important special cases. • Phenomenological/behavioral models for situations where the rigorous physical theories are too difficult to apply. 3

  4. Hierarchy of Physics Theories Involved in the Study of Electrical Engineering • Quantum electrodynamics • Quantum mechanics • Schrödinger equation • Classical electromagnetics • Electrostatics • Electrodynamics • Circuit theory • Geometric optics 4

  5. Maxwell’s Equations 5

  6. Information Theory • Originally developed by Claude Shannon of Bell Labs in the 1940s. • Information is defined as a symbol that is uncertain at the receiver. • The fundamental quantity in information theory is channel capacity – the maximum rate that information can be exchanged between a transmitter and a receiver. The material in this slide and the next has been adapted from material from www.lucent.com/minds/infotheory. 6

  7. Information Theory • Defines relationships between elements of a communications system. For example, • Power at the signal source • Bandwidth of the system • Noise • Interference • Mathematically describes the principals of data compression. 7

  8. Exercise: What is Information? • Message with redundancy: • “Many students are likely to fail that exam.” • Message coded with less redundancy: • “Mny stdnts are lkly to fail tht exm.” Claude Shannon, founder of Information Theory 8

  9. Digital Logic • Based on logic gates, truth tables, and combinational and sequential logic circuit design • Uses Boolean algebra and Karnaugh maps to develop minimized logic circuits. 9

  10. EE Subdisciplines • Power Systems • Electromagnetics • Solid State • Communication/Signal Processing • Controls • Analog/Digital Design 10

  11. Power Systems • Generation of electrical energy • Storage of electrical energy • Distribution of electrical energy • Rotating machinery-generators, motors 11

  12. Electromagnetics • Propagation of electromagnetic energy • Antennas • Very high frequency signals • Fiber optics 12

  13. Solid State • Devices • Transistors • Diodes (LED’s, Laser diodes) • Photodetectors • Miniaturization of electrical devices • Integration of many devices on a single chip 13

  14. Communications/Signal Proc. • Transmission of information electrically and optically • Modification of signals • enhancement • compression • noise reduction • filtering 14

  15. Controls • Changing system inputs to obtain desired outputs • Feedback • Stability 15

  16. Digital Design • Digital (ones and zeros) signals and hardware • Computer architectures • Embedded computer systems • Microprocessors • Microcontrollers • DSP chips • Programmable logic devices (PLDs) 16

  17. Case Study: C/Ku Band Earthstation Antennas Simulsat Parabolic Multiple horn feeds Horn feed ATCi Corporate Headquarters450 North McKemyChandler, AZ 85226 USA 17

  18. Case Study: C/Ku Band Earthstation Antennas Incoming plane wave is focused by reflector at location of horn feed. Geometric Optics 18

  19. Case Study: C/Ku Band Earthstation Antennas Feed horn is designed so that it will illuminate the reflector in such a way as to maximize the aperture efficiency. Maxwell’s equations 19

  20. Case Study: C/Ku Band Earthstation Antennas Feed horn needs to be able to receive orthogonal linear polarizations (V-pol and H-pol) and maintain adequate isolation between the two channels. V-pol H-pol 20

  21. Case Study: C/Ku Band Earthstation Antennas A planar orthomode transducer (OMT) is used to achieve good isolation between orthogonal linear polarizations. Maxwell’s Equations (“Full-Wave Solution”) 21

  22. Case Study: C/Ku Band Earthstation Antennas To LNB Feed waveguide (WR 229) Maxwell’s equations Horn Stripline circuit with OMT, ratrace and WR229 transitions 22

  23. Case Study: C/Ku Band Earthstation Antennas Layout of the stripline trace layer Single-ended probe WR229 Transitions Circuit Theory Differential-pair probes Ratrace hybrid 50 ohm transmission line Vias 23

  24. Case Study: C/Ku Band Earthstation Antennas The two linear polarizations each are fed to a LNB (low noise block). LNB LNB 24

  25. Case Study: C/Ku Band Earthstation Antennas LNB: Mixer BPF LNA IF Output: 950-1750 MHz (To Receiver) Circuit Theory, Behavioral Models, Information Theory Local Oscillator 25

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