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Highly Scalable Packetised correlators. Jason Manley CASPER workshop 2009. Contents. Where we’ve come from CASPER Correlator design Dataflow Engine operations Scalability Present and future deployments. In the beginning…. Big dish. Control & Monitoring. Analogue processor.
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Highly Scalable Packetised correlators Jason Manley CASPER workshop 2009
Contents • Where we’ve come from • CASPER • Correlator design • Dataflow • Engine operations • Scalability • Present and future deployments
In the beginning… Big dish Control & Monitoring Analogue processor Computing backend
Interferometry… Green Bank 300ft ATA
…more recently… EVLA baseline board (Carlson, 2006)
CASPERCenter for Astronomy Signal Processing and Electronics Research • Open-source, collaborative environment • Reusable, platform-independent gateware • Modular, upgradeable hardware • Low instrument NRE, shared by the community • Enables rapid development (8 instruments / 2 years) • Industry standard communication protocols • Low Cost
Clocking • Clocks: • Locally synchronous, globally asynchronous. • Sampling clock synchronized at F engines. • X engines each run off independent local clock. • Synchronized using global 1pps signal at ADCs • Propagated to X engines using out-of-band signaling on XAUI links. • Headers labeling and timestamping10GbE Ethernet packet data.
Processing power doubling every two years • V4 = ½ power requirements of V2Pro* * Manufacturers claim - Xilinx Inc.
Existing systems: PAPER - Green Bank • 8 dual-pol antennas, 150MHz. • 1st Generation: one BEE2 & four IBOBs. • First deployment of packetized system. • Continuous upgrades.
Existing systems: Northern Cross, Medicina, Italy • Designed and deployed in under 2 weeks. • 32 single-pol antennas, 32 MHz. • 1st Generation: • one BEE2 • eight IBOBs.
New deployments: KAT-7 • 7 dual-pol antennas, 400MHz. • Pure ROACH. • New control and monitoring interface (KATCP), coarse delay, high speed output (less than 100ms). • Expected early 2010.
New deployments: GMRT • 32 dual-pol inputs, 400MHz bandwidth. • Collaboration – shares design with KAT-7.
New deployments: PSA-32/64/128/256 • PAPER in South Africa, staged deployment • Up to 256 antennas, 100MHz • Generation 1.5 (IBOB+ROACH) initially, • Generation 2.5 (ROACH + ROACH-II) eventually. • First field deployment of ROACH system. • Correlator deployment starting in January!
Jason Manley jason_manley@hotmail.com