Master%20Clock%20for%20IceCube:%20First%20Year%20Implementation - PowerPoint PPT Presentation

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Master%20Clock%20for%20IceCube:%20First%20Year%20Implementation

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Title: PowerPoint Presentation Author: Gerald Przybylski Last modified by: Gerald Przybylski Created Date: 10/6/2004 4:46:16 AM Document presentation format – PowerPoint PPT presentation

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Title: Master%20Clock%20for%20IceCube:%20First%20Year%20Implementation


1
Master Clock for IceCubeFirst Year
Implementation
  • Gerald Przybylski
  • October 5, 2004
  • Lawrence Berkeley National Laboratory

2
The Big Picture
GPS Clock
Passive Fanout
DOM Hub
DOM Hub
DOM Hub
DOM Hub
DOM Hub
DOM Hub
DOM Hub
DOM Hub
DOM Hub
  • Temporary Counting House
  • 1 GPS Clock
  • 1 Passive Fanout
  • 9 DOM Hubs

8 Tuned Fanout cables for phase matching 18
Identical 32ns Fanout cables 1 serial daisy chain
cable
3
Goal
  • Strong requirement
  • 10 MHz Clock Delivered, in-phase, to all DOR
    cards, within fraction of a ns
  • Time-tick arrival to satisfy DOR FPGA firmware
    set-up and hold requirements
  • Weak requirement
  • Timely arrival of serial string, within 1ms

4
GPS Technology
  • TrueTime absorbed by Symmetricom
  • Symmetricom part of Datum Inc.
  • Performance Similar to other units at pole
  • OCXO Option for better Allan Variance
  • 10 MHz, 1Hz (or 1pps) and Serial Time string

5
Pulse and Timing Signals
  • Multiple RF/Pulse Outputs- Internal jumpers -
    MUX outputs (control by front panel, or serial
    port)- Specialized (option) outputs
  • IceCubes needs- Three 10 MHz outputs (sine)
    Fixed outputs J3e, J3f, J7- Five 1 Pulse per
    Second (or 1 Hz) Mux selected outputs J4,
    J5, J6, J8, J9
  • Phasing required Tuned Cables for all outputs

6
Passive Fanout
  • 12 and 13 Resistive Matching Networks
  • Simple, but effective
  • Economical
  • Trouble-free

7
Time String
  • Similar (standard?) time string format
  • 1-second Burst format from printer port
  • Content options - Like TrueTime string
    dddhhmmssq - Optional data suppressed by
    mode control
  • ltcrgtltlfgt lt1ms after 1pps (1Hz) rising edge
  • Firmware soon Kalle, and John Jacobsen
  • Daisy-Chain fan-out cable required

8
Status
  • GPS clocks Procured and Tested
  • Passive Fan-out Fabricated and Tested
  • Tuned BNC cables Fabricated and Tested
  • Identical LEMO Cables On Order
  • Shipment to Wisconsin Imminent
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