DAQ Verification for Rescue 21

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DAQ Verification for Rescue 21

• 1/c Jennifer M. Jojola
• Project Advisors CAPT Hartnett,
• Dr. Gross, LCDR Routhier
• Sponsor Rescue 21, (G-AND)

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Outline of Talk

• What is Delivered Audio Quality (DAQ)?
• Why pursue this initiative?
• Focus
• Results
• Next year

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Introduction

• What is DAQ?
• Why do we need to assess DAQ?
• Impact communication will have.
• Relevance to the U.S. Coast Guards mission.

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Background

• DF and DAQ projects given to USCGA
• Class of 2003 Project
• Required Performance Standard

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DAQ Table
Telecommunications Industry Association Technical
Services Bulletin
SINAD (signalnoisedistortion) /
(noisedistortion)
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Objectives

• Distinguish signal and noise
• Propose an algorithm that calculates SINAD
• Present the testing methodology to Rescue 21
• Testing on Rescue 21 systems

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2 Approaches

• Technical Approach A
• Unknown transmitted signal
• Technical Approach B
• Known transmitted signal

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Technical Approach A

• Unknown Transmitted Signal
• Establish Power Threshold
• Verify Suspect Signal Areas
• SINAD
• DAQ

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Block Diagram
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Mayday
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Threshold

• Separate Data Suspect Signal Noise.
• Threshold Average of Mean and RMS

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Suspect Signal Areas

• Determine which are signal and which are high
  power noise
• Criteria for signal present
• Minimum time duration
• Low frequency

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Verify Signal

• Minimum Time Duration
• Certain number of samples
• Eliminates Spikes
• Low Frequency
• Percentage of Zero Crossings
• Eliminates Hiss

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Final Signal Areas

• New Categorized Signal

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Calculation

• Calculate SINAD
• SINAD value corresponds to DAQ value

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Revised Block Diagram
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2 Approaches

• Technical Approach A
• Unknown transmitted signal
• Technical Approach B
• Known transmitted signal

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Technical Approach B

• Known transmitted audio file
• Received signal
• Find known signal within the received
• Determine noise
• SINAD
• DAQ

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Transmitted Signal

• Known Signal

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Received Signal
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Transmitted Received
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Determined Noise
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Finding DAQ Value

• SINAD
• DAQ

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Results

• 2 Technical Approaches

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Conclusions Approach A

• Unknown Transmitted Signal
• 3 areas explored of an unknown signal
• Threshold
• Minimum Time Duration
• Low Frequency

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Results Approach A
DAQ
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Conclusions Approach B

• Known Transmitted Signal
• Correlation Techniques
• Using Transmitted and Received Signals
• Estimated Signal and Noise
• Estimated SINAD
• DAQ

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Results Approach B
DAQ
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Future

• Implement
• Gather Live Data and Measure DAQ in Real Time.
• Propose Testing Specification and Methodology

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Semper Paratus
Semper Paratus

• ANY QUESTIONS?