Highly Scalable Packetised correlators

yakzephyrAI and Robotics

Nov 24, 2013 (3 years and 9 months ago)

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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…

Computing
backend

Analogue
processor

Control &
Monitoring

Big
dish

Interferometry


ATA

Green Bank 300ft

…more recently…

EVLA
baseline
board

(Carlson, 2006)

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


CASPER DBE concept

CASPER DBE concept

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.

Correlator

Overview

How does it scale?

1
10
100
1000
10000
100000
1000000
F Engines
X Engines
43

100

200

330

760

0
100
200
300
400
500
600
700
800
1998
2000
2002
2004
2006
2008
2010
Logic Cells (thousands)

Xilinx
Virtex

Family


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.


1
st

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.


1
st

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