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Conv RS485 OPT RTM
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Last edited by Evangelia Gousiou Apr 29, 2019
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RS485 to Optical Converter VME RTM

Project Description

Overview

The CONV-RS485-OPT-RTM (*) is a VME rear transition module providing fiber-optic and electrical inputs and outputs. In combination with the CONV-TTL-RS485 as front-module it provides TTL to optical conversion. The interface with the CONV-TTL-RS485 is through internal RS485 signaling.

The board provides three channels. On the optical side, each channel consists of one input (IN) and two outputs (O1 and O2). Within each channel, the two outputs are driven by the same signal source, using two separate optical transmitters.

The design is based on the following existing modules:

optical transmitter CTDAB
optical receiver CTDPR

(*) Note on project name: After discussion, this was the name selected for the board. It does not comply with other RTM names fron the conv-ttl-xxx family such as the conv-ttl-rtm-blo, conv-ttl-rtm-rs485, conv-ttl-rtm-rs485-db9. Since no TTL signals are involved in this board, the TTL is removed. Furthermore, this board is described first by it's signal interface (RS485 to Toptical), then by the RTM description, in the same way as the conv-ttl-rtm motherboard (without piggyback)

Specifications

Parameter Value
Number of channels 3
Optical inputs per channel 1
Optical outputs per channel 2
Wavelength 1310nm
Supported fiber type Single mode
Fiber connector ST
Optical power output ~ 350uW average (~700uW peak)
Optical power input min 8uW average (16uW peak)
pulse width distortion effects > 80uW peak
Allowed attenuation max 10dB (10km fiber with 10 connections)
Optical signal characteristics Transmission/ Reception of CERN's GMT signal (500 kHZ DC balanced signal) and of single pulses:
Minimum pulse width: 100 ns
Maximum frequency: 1 MHz
Maximum pulse width: 1 ms
Minimum frequency: None, as long as maximum pulse width is respected
Latency (μ) < 250 ns (see also Pulse-Repetition-Performance-Measurements)
Jitter (2σ) <200 ps (see also Pulse-Repetition-Performance-Measurements)

Versions

Version Hardware Design Files
1.1 * EDA-03760-V1-1
1.0 EDA-03760-V1-0

Documentation

  • Hardware-Guide

Project Information

  • Design-notes
  • Pulse-Repetition-Performance-Measurements
  • V1-Schematic-Review
  • V1-PCB-Review
  • Level Conversion project
  • Presentation on level converter boards
  • Presentation on design specification
  • Production Test Suite

Status

**** ****
15-07-2017 Start working on project.
06-09-2017 First schematics for a prototype.
27-10-2017 Prototypes received
06-12-2017 Prototypes validated
08-12-2017 Meeting and presentation to discuss design choices and outstanding issues
15-12-2017 V1-Schematic-Review held at CERN BE-CO-HT
02-02-2018 V1-PCB-Review held at CERN BE-CO-HT
22-02-2018 Board moved to production of 5 prototypes
05-04-2018 5 v1.0 prototypes have been received. Now to be tested
03-05-2018 Prototypes validated in the labs. Now being tested in CERN installations
28-06-2018 Order made for 800 pieces of the FD13R0S1STXS-4BX4 sugar cube transmitters
01-10-2018 Transmitters received, 120 boards in production
Clone repository
  • Design notes
  • Documents
  • Hardware guide
  • Home
  • Pulse repetition performance measurements
  • Pts first time setup
  • V1 pcb review
  • V1 schematic review
  • Documents
    • Hardware guide
    • Pictures
    • Presentation on optical repeater design
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