VRB Transition Module (VTM-II)

  • Converts serial optical data to 20-bit TTL parallel data
  • Four 1.5 Gb/sec(max.) serial optical inputs w/ ST connectors
  • Single Width 9U x 120mm VIPA Transition Module
  • Conforms to VME64x/VIPA , 9U x 400 Format VITA 1.3, Draft .7
  • Monitor & Control provided by one microcontroller  per channel to:
    • Monitor Optical Power of each channel
    • Moitor signal detect of optical device
    • Reset individual HP Glink devices
    • Inhibit switching of output data buffers
  • Extensive use of pi filters, ferrite beads to reduce switching noise
  • 14 layer pc board w/ 6-layers ground plane to:
    • provide 50-ohm striplines for all high speed signals
    • Minimize channel-to-channel cross-talk


The VRB Transition Module (VTM-II) is basically a high speed serial to parallel converter incorporating four  1.5Gbit/s(max) serial optical receiver channels on a single width 9U x 120mm standard module (VITA 1.3, draft .7). This module was specifically designed to provide a replaceable optical front-end for the VME Readout Module (VRB) to ease its real estate burden. The VTM-II user inputs to this module is via front panel optical ST connectors. The input optical data is received and converted to a differential ECL data stream by a Finisar FRM-8510 device. The serial bit stream  output of the Finisar device is then converted to 20-bit parallel data word by Hewlett Packards's TTL G-Link chip (part# HMP-1024). Each of the four 20-bit parallel TTL data channels is presented to the P5/P6 VME connector for input to the VRB. Also, the VTM-II  has an 8-pin microcontroller per channel to provide minimal control and monitoring functions (example: optical receiver power, signal detect and channel reset commands). Extensive use of high speed techniques were incorporated into the pc board (firrite beads, pi filters and stripline vs typical microstrip lines)

Additional Technical Information

Block Diagram


Detail Picture

Project Schedule

Module Status

Module Log

Additional Technical Information (PDF Format)
Specification Schematic Parts List PC Artwork PC Fabricaton PC Stiffener Assembly Front Panel