CMS Document 2631-v2

QPLL and related crystal

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Submitted by:
Evgueni Vlassov
Updated by:
Paulo Rodrigues Simoes Moreira
Document Created:
02 Jul 2010, 17:01
Contents Revised:
13 Sep 2010, 10:32
Metadata Revised:
23 Jul 2015, 09:25
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Documentation relating to the QPLL and the crystal supposed to be used with it. Includes note on the locking mechanism, the datasheet, QPLL measurements, a status report covering issues with the QLL (2004) and the 2009 manual. See version 1 of this document for the 2005 manual.

Preliminary manual for the Quartz Crystal Based Phase-Locked Loop (QPLL) for Jitter Filtering Application in LHC.

The QPLL is a Quartz crystal based Phase-Locked Loop. Its function is to act as a jitter-filter for clock signals operating synchronously with the LHC bunch-crossing clock. Two frequency multiplication modes are implemented: 120 MHz and 160 MHz modes1. In the 160 MHz mode, the ASIC generates three clock signals synchronous with the reference clock at 40 MHz, 80 MHz and 160 MHz while in the 120 MHz mode the synthesized frequencies are 40 MHz, 60 MHz and 120 MHz. In both cases, the highest frequency is generated directly from a Voltage Controlled Crystal Oscillator (VCXO) and the lower frequencies are obtained by synchronous division. The two frequency multiplication modes require Quartz crystals cut to the appropriate frequencies.

Notes and Changes:
Replaced 2005 manual with 2009 (v. 1.3)
Related Documents:
  • CMS-doc-2954: Technical Documentation - Front End (FE) Electrical Components
Referenced by:
  • CMS-doc-2632: ECAL Communication and Control Unit ASIC (CCU-25) Overview (DRAFT) and Pin List
  • CMS-doc-3287: Quartz Crystal Based Phase-Locked Loop (QPLL) Lock Frequency Tests
  • CMS-doc-12596: igloo2 UMd mezzanine production 2015