Hybrid Support Vector Machine/Hidden Markov Model for Continuous Speech Recognition Prof Gert Cauwenberghs

1
Introduction
ECE 418 Algorithms of Circuit Design (Fall 2005)
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Algorithms of circuit design

• What is the purpose of a circuit ?

• How many classes of circuits exist ? ( Digital,
  Analog, Mixed-signal)

• Algorithms of Digital Circuit Design ? ( ECE 230,
  331, 302, 410, 411)
• Algorithms of Analog Circuit Design ?

3
Why Analog ?

• Our environment is predominantly analog.

Image/Acoustics/sensory signal

• Biomedical applications, audio applications etc.

4
Communication and storage systems

• Our environment is predominantly analog.

Digital communication systems
High density storage systems

• Whenever a signal interacts with noise and
  physical environment analog processing play an
  important role.

5
Ubiquitous Electronics
Nanotechnology
Fingerprint sensors
Implantable Devices
DNA sensors and Gene Chips
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Why not focus on just A/D ?

• Take a look at this picture taken using a
  traditional digital camera.
• Can you locate a person in the picture ?
• Once the picture is quantized with an A/D
  information can not be retrieved.
• Analog signal processing could dynamically adjust
  the pixel resolution and dynamic range.

7
Masterpieces of Nature

• Information processing in nature is analog.
• Till date no man-made sonar can match the
  performance of a bat.
• Parasitoid fly (O.Ochracea) can localize sound of
  crickets with an accuracy less than 2 degrees.

Nature, vol.429, 2004
Nature, vol.410, 2001
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Analog Circuit design and Industry

• Amplifiers, A/D converters, Regulators, DC-DC
  converters, radio-frequency circuits.
• Analog circuit design is 60 art and 40 science.
  Possibility of implementing a function in several
  different ways.
• Several big players in the market Intel, Analog
  Devices, Maxim, Texas Instruments,..

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Challenge of Analog Circuit Design

• - Digital circuits deal primarily with speed
  power tradeoff.
• - Analog circuits deal with multi-dimensional
  tradeoff of speed, power, gain, precision,
  supply,
• - Due to speed and precision requirements, analog
  circuits are much more sensitive to noise,
  crosstalk, and other interferers.

Precision
Speed
Power
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Challenge of Analog Circuit Design

• - Analog circuits are much more sensitive to
  second-order device effects
• - High performance analog circuit design can
  rarely be automated - typically require
  hand-crafted design and layout
• - Modeling and simulation of analog circuits is
  still problematic, requiring experience and
  intution

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Challenge of Analog Circuit Design

• - Economic forces require the development of
  analog circuits in mainstream digital processes
• - Economic forces pushing the integration of
  analog and digital functions onto a single
  substrate
• - Many levels of abstraction are required