100 likes | 180 Views
eVLBI System Integration. Maintain Production Recording Support Production eVLBI Must support 'Local Station' Should support Cm or equiv. Outstation eMerlin changeover/disruption Recording data for 3-5 years plus is likely. Local or 'Home' Station. Old Mk4 Racks failure buildup starting
E N D
eVLBI System Integration • Maintain Production Recording • Support Production eVLBI • Must support 'Local Station' • Should support Cm or equiv. Outstation • eMerlin changeover/disruption • Recording data for 3-5 years plus is likely
Local or 'Home' Station • Old Mk4 Racks failure buildup starting • Need more space in room • Need reduced maintenance • Best solution is Haystack DBE2 - Low cost - NRAO writing VLBI Mode codes - Has IF Hardware
Cambridge (or other) • eMerlin means no analog signal • Convert data format eM->VLBI/VSI • VLBI needs geometry rate 'turned off' – clashes with combined EN/Merlin • Requires 'VSI Xilinx' FPGA Development • Correlator box should have fibre I/O • Therefore send 1 or 10GE to Mark5's.
Recorded Data to Mark5 • Referring to Outstaion Mark5(s)/Recording • Mark5B Upgrades already purchased (cannot yet deploy – March 08?) • VSIE data i/p then becomes available – but VSIE cables are copper (but can be done) • Maybe – send IP data from switch to Mark5 • Should be possible to record a la JIVE • Late 08 – Mark5C – 10GE Compatible!
I, Bob.. • 10GE capacity independent of 1G production eVLBI – But – Correlator Data geo. problem • Consider sending outstation data direct to Jive also for recording? (they won't like it, would need to change diskpacks) • Originally we included 'Reverse iBob' to convert fibre 1G back to VSI - • Probably better to stick with Mark5C solution
Actions • Purchase 20GE Switch • PB pursuing DBE2 'Insurance Policy' • PB Pursue pricing of DBE2 (Haystack) • Need strategy for: - Switching between eMerlin/VLBI - Combined eMerlin/VLBI • Consider: Two extra Station Boards (Cost)
Options and Alternatives • No combined EVN/Merlin w. outstations • No outstation recording for period X months • Substitute Fabric for combined EVN/Merlin • But Note: Recording will continue. • Avoid connector-based 'switching' • Will need local control software (PB)