ECE310

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ECE310 Lecture 1

• Introduction to Signals and Systems
• 01/10/00

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Signals and Systems

• Practically everything around us can be thought
  of as either a signal or a system.

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Signals

• Any time-varying physical phenomenon which is
  intended to convey information
• Is constant speed a signal???
• Examples ???

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Different Signals

• Based on how it is defined over time
• Continuous-time signal (analog signal)
• Defined at every instant of time over some time
  interval
• Discrete-time signal
• Only has defined values at discrete points in
  time
• Digital signal the transmitted discrete-time
  signal
• Based on how the future value is predicted
• Deterministic signal
• The signal can be mathematically described
• Random signal (noise)
• Can we describe a continuous-time random
  signal???
• Can we describe a discrete-time random signal???

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Examples
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Systems

• The entity that processes signals
• An abstraction of anything that takes an input
  signal, operates on it, and produces an output
  signal.
• Examples ???

x
y
System
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Linear, Time-Invariant (LTI) System

• LTI - A special subclass of systems
• Whats linear?
• Whats time-invariant?
• The system responds the same no matter what time
  the input is presented

Linear System
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Summary

• Signals
• Deterministic signals
• Continuous-time signals
• Discrete-time signals
• Random signals
• Systems
• LTI system