Toshiba RF Receiver for HDTV

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Toshiba RF Receiver for HDTV

• Presentation 1 10/21/2004

Team Josue Caballero, Brett DiCio, Daniel
Hooper, Efosa Ojomo, George Sewell
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Work Accomplished in the Past Week

• Met with our sponsor at Toshiba
• Aaron Foster
• Toured the factory and assembly line
• Discussed the current situation and defined the
  problem to be addressed
• Outlined and determined the work that needed to
  be done by the group

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Description of the Problem

• Toshiba currently uses an antenna attached to the
  end of a Coax line to broadcast to a TV with a
  small receiver antenna
• Current Design
• Transmission distance of 2 to 3 centimeters
• Inefficient Tauroid-shaped transmission antenna
• Problems
• Signal is being broadcast indiscriminately, being
  received on TVs that are not being tested
• Cannot determine the dB Gain of the received
  signal
• Goal
• Develop an antenna solution that can be used for
  multiple assembly lines without having to deal
  with errant signal noise and but with a
  consistent dB Gain

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Left Side
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Right Side
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Top View
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Current Setup

• Workers unpack guts and chassis and assemble
  them.
• TVs placed on a roller line
• TVs move from one station to the next, stopping
  at each station
• First half of testing line is automated

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Automation

• Each station has a small antenna that lines up
  with TV whip antenna
• In front of TV, a computer makes adjustments
• Digital video camera input
• TV remote control output

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Manual Cable Placement

• Required because of antenna signal strength is
  unreliable
• Need to test v-chip and closed captioning at
  various signal levels for certification

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Motivation

• Labor cost for a simple task like plugging in a
  cable is high
• Automated adjustment is free of human variances

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Introduction to Antennas

• Electronic components designed to send and
  receive radio waves
• Used for transmission and reception of radio
  frequency signals like TV signals (signals can
  pass through non-conducting surfaces _at_ speed of
  light)
• HDTV antennas are the same as conventional TV
  antennas

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Different Antenna models

• Dipole Antenna
• Simplest TV antenna
• Omni-directional in plane perpendicular to axis
  of antenna
• Variations include the folded dipole
  (efficiency), bowtie dipole (bandwidth), and loop
  dipole
• Gain 2.5dBi
• Example Rabbit ears on TV

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Illustration of dipole antennas
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Stacked Dipoles

• Two heads are better than one
• N dipoles will take in N times as much RF power
  as one dipole
• Dipoles are commonly stacked horizontally
  (collinearly), vertically (broadside), and in
  echelon (end-fire).

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Different stacking methods
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Reflector Antennas

• Radio waves reflect off a large conducting plane
  like a mirror
• They are very common
• Examples
• Screen Reflector
• Parabolic Reflector (high gain, expensive)
• Corner Reflector (less gain more bandwidth)
• Paraboloid Reflector

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Illustration of reflector antennas
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Fundamentals

• Maxwells Equations
• Understanding Transmission
• Vocabulary
• E Electric field
• B Magnetic flux density
• Curl and Divergence

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Maxwell's Equations
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Recieving

• Maxwell transmissions
• Antenna reacts
• Electromagnetic energy
• Current
• Picture/Sound
• Creating an antenna
• Frequency design

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Interference Shielding

• The factory has several production lines running
  alongside each other, because of the wireless
  transmission there is a high probability of
  interference
• The signals can interfere and tests might not
  return good results
• One possible solution is shielding

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Shielding

• Two styles of design
• Active Generating an opposing field
• Passive Blocking stray fields
• There are several materials that can be used in
  shielding including plastic, concrete and metal
• Method and Material is a question of cost versus
  need
• We are going to researching the need for
  shielding and determining the best solution

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To-Do List for Next Week

• Finish an outline and draft of the requirements
  document for Toshiba
• Obtain an understanding on how the current
  Toshiba design works
• Determine a list of possible antenna
  designs/structures to be researched
• Continue researching methods for shielding a test
  station from noise

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Resources

• http//www-pw.physics.uiowa.edu/plasma-wave/istp/p
  olar/fig3.gif
• http//scienceworld.wolfram.com/physics/MaxwellEqu
  ations.html