1 overview of electrical engineering lecture 8a: introduction to engineering

1

Overview of Electrical Overview of Electrical EngineeringEngineering

Lecture 8A:Lecture 8A:

Introduction to Introduction to EngineeringEngineering

2Lecture 1

Foundations of Electrical Foundations of Electrical EngineeringEngineering

ElectrophysicsElectrophysics Information Information

(Communications) (Communications) TheoryTheory

Digital LogicDigital Logic

3Lecture 1

Foundations of Electrical Foundations of Electrical EngineeringEngineering

ElectrophysicsElectrophysics:: Fundamental theories of physics Fundamental theories of physics

and important special cases.and important special cases. Phenomenological/behavioral Phenomenological/behavioral

models for situations where the models for situations where the rigorous physical theories are too rigorous physical theories are too difficult to apply.difficult to apply.

4Lecture 1

Hierarchy of Physics Theories Hierarchy of Physics Theories Involved in the Study of Involved in the Study of Electrical EngineeringElectrical Engineering

Quantum electrodynamicsQuantum electrodynamics Quantum mechanicsQuantum mechanics

Schrödinger equationSchrödinger equation Classical electromagneticsClassical electromagnetics

ElectrostaticsElectrostatics ElectrodynamicsElectrodynamics Circuit theoryCircuit theory Geometric opticsGeometric optics

5Lecture 1

Maxwell’s EquationsMaxwell’s Equations

6Lecture 1

Information TheoryInformation Theory Originally developed by Claude Originally developed by Claude

Shannon of Bell Labs in the 1940s.Shannon of Bell Labs in the 1940s. InformationInformation is defined as a symbol that is defined as a symbol that

is uncertain at the receiver.is uncertain at the receiver. The fundamental quantity in The fundamental quantity in

information theory is information theory is channel capacitychannel capacity – – the maximum rate that information the maximum rate that information can be exchanged between a can be exchanged between a transmitter and a receiver.transmitter and a receiver.

The material in this slide and the next has been adapted from material from www.lucent.com/minds/infotheory.

7Lecture 1

Information TheoryInformation Theory

Defines relationships between Defines relationships between elements of a communications elements of a communications system. For example,system. For example, Power at the signal sourcePower at the signal source Bandwidth of the systemBandwidth of the system NoiseNoise InterferenceInterference

Mathematically describes the Mathematically describes the principals of data compression.principals of data compression.

8Lecture 1

Exercise: What is Exercise: What is Information?Information?

Message with redundancy:Message with redundancy: ““Many students are likely to fail Many students are likely to fail

that exam.”that exam.” Message coded with less Message coded with less

redundancy:redundancy: ““Mny stdnts are lkly to fail tht Mny stdnts are lkly to fail tht

exm.”exm.”Claude Shannon, founder of Information Theory

9Lecture 1

Digital LogicDigital Logic Based on logic gates, truth Based on logic gates, truth

tables, and combinational and tables, and combinational and sequential logic circuit design sequential logic circuit design

Uses Boolean algebra and Uses Boolean algebra and Karnaugh maps to develop Karnaugh maps to develop

minimized minimized

logic circuits. logic circuits.

10Lecture 1

EE SubdisciplinesEE Subdisciplines

Power SystemsPower Systems ElectromagneticsElectromagnetics Solid State Solid State Communication/Signal Communication/Signal

ProcessingProcessing ControlsControls Analog/Digital DesignAnalog/Digital Design

11Lecture 1

Power SystemsPower Systems

Generation of electrical energyGeneration of electrical energy Storage of electrical energyStorage of electrical energy Distribution of electrical energyDistribution of electrical energy Rotating machinery-generators, Rotating machinery-generators,

motorsmotors

12Lecture 1

ElectromagneticsElectromagnetics

Propagation of electromagnetic Propagation of electromagnetic energyenergy

AntennasAntennas Very high frequency signalsVery high frequency signals Fiber opticsFiber optics

13Lecture 1

Solid StateSolid State

DevicesDevices TransistorsTransistors Diodes (LED’s, Laser diodes)Diodes (LED’s, Laser diodes) PhotodetectorsPhotodetectors

Miniaturization of electrical Miniaturization of electrical devicesdevices

Integration of many devices on a Integration of many devices on a single chipsingle chip

14Lecture 1

Communications/Signal Communications/Signal Proc.Proc.

Transmission of information Transmission of information electrically and opticallyelectrically and optically

Modification of signalsModification of signalsenhancementenhancementcompressioncompressionnoise reductionnoise reductionfilteringfiltering

15Lecture 1

ControlsControls

Changing system inputs to Changing system inputs to obtain desired outputsobtain desired outputs

FeedbackFeedback StabilityStability

16Lecture 1

Digital DesignDigital Design

Digital (ones and zeros) signals and Digital (ones and zeros) signals and hardwarehardware

Computer architecturesComputer architectures Embedded computer systemsEmbedded computer systems

MicroprocessorsMicroprocessors MicrocontrollersMicrocontrollers DSP chipsDSP chips Programmable logic devices (PLDs)Programmable logic devices (PLDs)

17Lecture 1

Case Study: C/Ku Band Earthstation Case Study: C/Ku Band Earthstation Antennas Antennas

ATCi Corporate Headquarters450 North McKemyChandler, AZ 85226 USA

SimulsatParabolic

Horn feed

Multiple horn feeds

18Lecture 1

Case Study: C/Ku Band Earthstation Case Study: C/Ku Band Earthstation Antennas Antennas

Incoming plane wave is focused by reflector at location of horn feed.

Geometric Optics

19Lecture 1

Case Study: C/Ku Band Earthstation Case Study: C/Ku Band Earthstation Antennas Antennas

Feed horn is designed so that it will illuminate the reflector in such a way as to maximize the aperture efficiency.

Maxwell’sequations

20Lecture 1

Case Study: C/Ku Band Earthstation Case Study: C/Ku Band Earthstation Antennas 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

21Lecture 1

A planar orthomode transducer (OMT) is used to achieve good isolation between orthogonal linear polarizations.

Case Study: C/Ku Band Earthstation Case Study: C/Ku Band Earthstation Antennas Antennas

Maxwell’s Equations (“Full-Wave Solution”)

22Lecture 1

Case Study: C/Ku Band Earthstation Case Study: C/Ku Band Earthstation Antennas Antennas

Horn

Feed waveguide (WR 229)

To LNB

Stripline circuit with OMT, ratrace and WR229 transitions

Maxwell’sequations

23Lecture 1

Case Study: C/Ku Band Earthstation Case Study: C/Ku Band Earthstation Antennas Antennas

Single-ended probe

Differential-pair probes

Ratrace hybrid

WR229Transitions

50 ohm transmission line

Layout of the stripline trace layer

Vias

Circuit Theory

24Lecture 1

Case Study: C/Ku Band Earthstation Case Study: C/Ku Band Earthstation Antennas Antennas

The two linear polarizations each are fed to a LNB (low noise block).

LNB

LNB

25Lecture 1

Case Study: C/Ku Band Earthstation Case Study: C/Ku Band Earthstation Antennas Antennas

LNB:

LNA Mixer

IF Output:950-1750 MHz(To Receiver)

Local Oscillator

BPF

Circuit Theory,

Behavioral Models,

Information Theory