DIGITAL SYSTEMS

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DIGITAL SYSTEMS

• ECE-273, Digital Systems
• Dr. Herb Kaufman
• Electrical and Computer Engineering
• UofM-Dearborn
• www.engin.umd.umich.edu/hkaufm/273files

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Required Textbook

• Fundamentals of Logic Design 5th Edition
• Charles H. Roth, Jr.
• ISBN 0-534-37804-8
• (C) 2004

-- See Syllabus for further information about the
course
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Analog versus Digital
Analog Voltage meter
Digital Voltage meter
103.5
About 100
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Analog Continuous Spectrum
Digital Distinct Steps
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Analog vs. Digital

• Analog
• Continuous
• Time
• Every time has a value associated with it, not
  just some times
• Magnitude
• A variable can take on any value within a range
• e.g.
• temperature, voltage, current, weight, length,
  brightness, color

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Analog vs. Digital

• Digital
• Discontinuous
• Time (discretized)
• The variable is only defined at certain times
• Magnitude (quantized)
• The variable can only take on values from a
  finite set
• e.g.
• Switch position, digital logic, Dow-Jones
  Industrial, lottery, batting-average

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Analog to Digital

• A Continuous Signal is Sampled at Some Time and
  Converted to a Quantized Representation of its
  Magnitude at that Time
• Samples are usually taken at regular intervals
  and controlled by a clock signal
• The magnitude of the signal is stored as a
  sequence of binary valued (0,1) bits according to
  some encoding scheme

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Quantization

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Digital to Analog

• A Binary Valued, B 0, 1 , Code Word can be
  Converted to its Analog Value
• Output of D/A Usually Passed Through Analog Low
  Pass Filter to Approximate a Continuous Signal
• Many Applications Construct a Signal Digitally
  and then D/A
• e.g., RF Transmitters, Signal Generators

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Digital is Ubiquitous

• Electronic Circuits based on Digital Principles
  are Widely Used
• Automotive Engine/Speed Controllers
• Microwave Oven Controllers
• Heating Duct Controls
• Digital Watches
• Cellular Phones
• Video Games

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Why Digital?

• Increased Noise Immunity
• Reliable
• Inexpensive
• Programmable
• Easy to Compute Nonlinear Functions
• Reproducible
• Small

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Digital Data Another Advantage

• Digital data can have additional data added to it
  to allow for detection and correction of errors
• -- (EDAC Error Detection and Correction)
• Digital data can be transmitted over a medium
  that introduces errors that are corrected at
  receiving end
• Satellite transmission of Direct TV - each
  screen image is digitally encoded errors
  corrected when it reaches your digital receiver,
  shows up as a Perfect Picture.

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Digital Design Process

• Computer Aided Design Tools
• Design entry
• Synthesis
• Verification and simulation
• Physical design
• Fabrication
• Testing

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