1. Highly Scalable Packetised correlators Jason Manley CASPER workshop 2009

2. Contents Where we’ve come from CASPER Correlator design Dataflow Engine operations Scalability Present and future deployments

3. In the beginning… Computing backend Analogue processor Control & Monitoring Big dish

4. Interferometry… ATA Green Bank 300ft

5. …more recently… EVLA baseline board (Carlson, 2006)

6. CASPER Center 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

7. CASPER DBE concept

9. 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 timestamping 10GbE Ethernet packet data.

10. Correlator Overview

11. How does it scale?

12. Processing power doubling every two years V4 = ½ power requirements of V2Pro* * Manufacturers claim - Xilinx Inc.

13. Existing systems: PAPER - Green Bank 8 dual-pol antennas, 150MHz. 1 st Generation: one BEE2 & four IBOBs. First deployment of packetized system. Continuous upgrades.

14. Existing systems: Northern Cross, Medicina, Italy Designed and deployed in under 2 weeks. 32 single-pol antennas, 32 MHz. 1 st Generation: one BEE2 eight IBOBs.

15. 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.

16. New deployments: GMRT 32 dual-pol inputs, 400MHz bandwidth. Collaboration – shares design with KAT-7.

17. 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!

18. Jason Manley jason_manley@hotmail.com