Introduction to Signals, Introduction to Systems, Why study signals and systems, Application areas of signals and systems

1. EEE 3107
Signals and Systems
Sadia Sultana
Assistant Professor,
Dept. of EEE
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2. Lecture 1
Introduction to Signals and Systems
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3.  Introduction to Signals
 Introduction to Systems
 Why study signals and systems
 Application areas of signals and systems
Outline
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4. What is Signals?
 Signal is a physical quantity that carry information.
 It is defined as a function of one or more independent variables.
 Signals can be one-dimensional or multidimensional.
 Example: Human voice, electrical signal, video, image etc.
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5.  System: A systems is a collection of elements or components that
are organized for a common purpose.
 Or System is a device or combination of devices, which can operate
on signals and produces corresponding response.
 Systems process input signals to produce output signals.
What is System?
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6.  Examples:
 A circuit involving a capacitor can be viewed as a system that transforms the
source voltage (signal) to the voltage (signal) across the capacitor.
 A CD player takes the signal on the CD and transforms it into a signal sent to
the loud speaker.
 A communication system is generally composed of three subsystems, the
transmitter, the channel and the receiver. The channel typically attenuates and
adds noise to the transmitted signal which must be processed by the receiver.
Systems (cont.)
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7.  Signals and Systems are fundamental to all engineering!
 It is the basis of all control and signal processing engineering.
 It provides the necessary tools to analyze any system(Electrical, mechanical,
chemical) mathematically.
 Successful completion of this course helps you learning further courses like
Control Systems, Optical Communication, Power Systems, Digital Signal
processing.
Why study Signals and Systems?
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8.  The concepts of signals and systems arise in a wide variety of areas:
 Communications
 Circuit design
 Biomedical engineering
 Power systems
 Control application
 Signal processing
Applications of Signals and Systems
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9.  Transmission of information (signal) over a channel.
 The channel may be free space, coaxial cable, fiber optic cable.
 A key component of transmission: Modulation (Analog and Digital
Communication).
Communication Applications
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Wireless communication and signal processing

10.  Industrial control and automation (Control the velocity or position
of an object)
 Examples: Controlling the position of a valve or shaft of a motor
 Important Tools:
 Time-domain solution of differential equations
 Transfer function (Laplace Transform)
 Stability
Control Application
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Motor valve

11. 11 Robotics
Autonomous Vehicle Drone

12.  Algorithm is used to modify signals in a way to make them more useful.
 Goals:
 Efficient and reliable transmission, storage and display of information
 Information extraction and enhancement
 Signal processing-applications like-
 Speech and audio processing
 Multimedia processing (image and video)
 Underwater acoustic
 Biological signal analysis
Signal Processing Application
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13.  Compression: Fast, efficient, reliable transmission and storage of data
 Applied on audio, image and video data for transmission over the Internet,
storage
 Examples: CDs, DVDs, MP3, MPEG4, JPEG
 Mathematical Tools:
Fourier Transform,
Quantization,
Modulation
Multimedia Application
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Image processing

15. JPEG Example
 JPEG uses Discrete-Cosine Transform (similar to Fourier Transform)
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16.  Examples:
 Brain signals (EEG)
 Cardiac signals (ECG)
 Medical images (x-ray, PET, MRI)
 Goals:
 Detect abnormal activity (heart attack, seizure)
 Help physicians with diagnosis
 Tools: Filtering, Fourier Transform
Biological Signal Analysis Application
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17.  Example
Brain waves are usually contaminated by noise and hard to interpret
Biological Signal Analysis Application
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18.  Identifying a person using physiological characteristics
Biometrics Application
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Fingerprint Face Recognition Iris Recognition

19.  Active noise cancellation: Adaptive filtering
 Headphones used in cockpits
 Digital Audio Effects
 Add special music effects such as delay, echo, reverb
 Audio signal separation
 Separate speech from interference
 Wind sound from music in cars
Audio Signal Processing
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20.  Filtering Example
Audio Signal Processing
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