Noise Cancellation: Two Microphone Approach

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Gunjan Pandey Harini Sundararaman Sudhanshu Vyas
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Outline

• Objectives
• Architecture
• Design Stages
• Issues (Expected and Faced)
• Progress
• Final week targets

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Objectives

• The aim is to receive speaker's voice noise at
  both the microphone which are kept at a known
  distance and then try to make an estimate of
  noise using the microphone which is farther from
  the speaker.
• The known information includes the x(t) n(t)
  value at M1 and x(t ?t1) n(t ?t2) at the
  other microphone.
• Current assumption is that both the microphones
  are far enough so that speaker's voice doesn't
  reach the microphone no 2

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Architecture
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Design Stages
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Theory
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Issues We Expected

• Synchronization of the microphones
• ADC
• Position of noise source with respect to the
  system
• microphones characteristics
• Level of Noise the system will be able to handle
• Proximity of the microphones wrt each other

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Additional Issues Faced

• No tech support for AD1981B
• Chip is in secondary mode on the ML507
• Doubt regarding two microphone support
• Made a generic controller instead of specific one
• Custom debug methods

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Progress

• Made AC'97 controller
• Integrated with MP0 for testing
• Read register values from AD1981B
• Long way to go

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Plans for last week

• Test Implementation of register writes
• Remove UART
• Change estimator algorithm

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Questions
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