Ultra Wideband Digital Wireless Link

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Ultra Wideband Digital Wireless Link

• By Matthew Carrier, Nicholas Merrill, Brandon
  Mui, Justin Burkhart
• Advisor Professor R.W. Jackson

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What is Ultra Wide Band?

• Ultra Wide Band (UWB) uses very low-powered,
  short pulsed radio signals to transfer data over
  a wide range of frequencies
• FCC Definition
• Signals must occupy bandwidth gt500MHz
• Or, signal bandwidth is 20 of the carrier
  frequency

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Why do we need Ultra Wide Band?

• High-tech designs require portability, speed,
  performance
• Portability
• UWB use multiple low-powered pulses ? low power
  consumption
• UWB data rate is inversely proportional to
  distance (thus short range)
• Speed
• Proposed to be between 40-600 Mb/s, and
  eventually up to Gb/s
• Performance
• Volume of information proportional to the
  frequency band
• More information ? better graphics, better
  resolution for RADAR, etc.

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Transmitted Reference UWB Systems

• Standard TR-UWB systems are dogged by
  implementation issues
• The receiver requires an extremely wideband delay
  element
• As a solution, Professor Goeckel has developed
  theory for Slightly Frequency Shifted Reference
  UWB

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Slightly Frequency Shifted UWB

• Rather then separating the data from the
  reference in time, this systems separates them in
  frequency
• Data and Reference pulse must be orthogonal in
  frequency
• This avoids using the extremely wideband delay
  element in the receiver
• Our project is to take Prof. Goeckels theory and
  prove the concept through building a scaled
  prototype

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Deliverables

• Transmitter/Receiver Electronics Prototype
• Transmitter/Receiver Antenna Prototype
• Packaging design is not part of project

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Transmitter
PLD
Input
X
S
Pulser
Oscillator
X

• Omni antenna
• Pulse Generator has pulses with picosecond rise
  times
• Oscillator used for frequency shifting of the
  pulses
• PLD is used for buffering of data

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Receiver
Integrator
X
PLD
X
Oscillator

• Omni antenna
• Oscillator at same frequency and phase as
  transmitter (sync not yet designed)
• PLD is for out-buffering of received data

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What is Missing?

• Need to design circuitry to synchronize the
  frequency shift oscillators
• Need to develop/buy integrator circuitry that can
  be triggered
• Integrator and PLD sampling also have sync issues
  that need to be worked out
• Antenna design has yet to be implemented
• An antenna in our channel has already been
  designed by grad students here at UMASS

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Pulse Generation Closer Look

• Create very fast pulses using Step Recover Diodes
  (SRD)

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MDR Specification

• Transmitter Receiver prototype built
• Built using modular components connected with
  coaxial cable
• No synchronization circuitry implemented
• No antenna implemented
• Antenna design prototype built
• Tested for gain, return loss, radiation
  patterns
• Synchronization Circuitry
• Will be designed independently from the prototype

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Questions/Suggestions?
?