Control Building Fiber Preliminary Design Review

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Control Building Fiber Preliminary Design Review

• December 5, 2001

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IF Signal Path
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CB Main Distribution Frame
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Cable Type Required

• Plenum Cable is required in the building
• 30-Fiber tight buffer cables will be used

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Control BuildingMain Distribution Frame
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MDF Components
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Termination Panel

• 876 fibers
• Provisions for 1200

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Rack Mount EDFA
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Data Quality and Format Preliminary Design Review

• December 5, 2001

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Bit Error Rates

• Continuous On-Line Monitoring
• Hardware and software Part of Receiver
• MCB access
• Error Flag Sent to the Correlator
• Single threshold error flag

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Transmitter Power

• Automated Test
• Measured at Each Laser
• Manual Test
• Can be measured at the Mux output
• Can be measured at the output of the De-Mux

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Optical Power

• Continuous Optical Power will be measured
• 1 tap
• The EDFA will measure the Optical Power
• MCB access
• Total optical power is not a good indicator of
  BER

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Eye Pattern

• Patch Panel
• Manual measurements during reconfiguration
• Complete Diagnostic
• Jitter
• Q Factor
• Noise Margin
• Rise / Fall times

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Test Patterns

• Generated at each Transmitter
• Nine Test Patterns
• No Sync, alternating 1/0, all Ones, all Zeros
• MCB controlled

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Frame Format
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Frame Implementation
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Divided Sync Word

• Required to Identify Correct 1/2 Sequence
• 10 Bits long,
• 6 bit identify Start-of-Frame
• Barker Sequence - equal Ones versus Zeros
• Three Stage Synchronization Process

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Three Stage Synchronization

• Stage 1 - Search bits for frame pattern
• Stage 2 Monitor for Correct sync
• Stage 3 If two Bad frames in a row
• or 2-out-of-8 fames are Bad
• Then Start Search Again

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Scrambling

• Frame Synchronous Scrambling
• Entire frame except sync bits
• Select pattern is modulo 2 added
• Pattern results in
• Equal number of Ones/Zeros providing
• Balance ac content, sufficient transitions
• Minimize low frequency content

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Timing Signals

• Metaframe Index
• Metaframe count
• 1 PPS
• 1 Pulse per 10 seconds

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Data Valid Signal

• Initiated at the antenna
• Toggle Switch
• MCB controlled
• Passed to correlator

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Check Sum - BER

• Each 19 bits Generate a check Sum
• Only odd of errors per 19 bits Detected
• One error per frame is an
• Error Rate of about 10-3

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