Georgina Harris 12-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
2-P2-Polarisations olarisations AAll ll DDigitaligitalDr Georgina Harris / Prof Tony Brown
SKADS System Design and Team Leader, University of Manchester
Thanks to the 2-PAD Team:Manchester Chris Shenton, Tim Ikin, Aziz AhmedSaid, Richard Whitaker,
Tony Brown, Dan Kettle, Mina Panahi
Oxford Mike Jones, Kris Zarb Adami, Sasha Shidewy
Cambridge Andrew Faulkner
Astron Jan Geralt bij de Vaate, Raymond van den Brink
2-P2-Polarisations AAll DDigital2-PAD2-PAD
Georgina Harris 22-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
2-PAD Aims2-PAD Aims
• To produce a flexible platform upon which to test a variety of subsystems for the Aperture Array for the SKA
• Digital beamforming – Prove it can be done
– Realistic technology projections for cost/ power
– Low self induced RFI
– Low cost interconnects are feasible
• Dual polarisation measurements
• Proof of calibration at tile level
Georgina Harris 32-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
2-PAD 2-PAD System Design System Design
+ve Reg
Ant.polarisation
LNA Analog Conditioning
PCB
Analog Interconnect
CAT7?
BunkerRFI Shield
PSU
Analogue Conditioning
.......
Total 128 inputs
64 elements x2 polarisations
Beam
combiner
Processor
.......
Output B
eams
4 off Beamformer.Processors
Processor
ControlProcessor
Lin
eT
x/Rx Control
Timestandard
Buffers
Fro
m o
the
r b
ea
mfo
rme
r pro
c.
Beam
former
Processing
DigitalPre-
processor
AD
C
PSUDigitalPre-
processor
AD
C
.....
.....Signal Conditioning RackSignal Conditioning Rack Processing RackProcessing Rack
BunkerOutdoors
64 dual channels
Up to ~20m
Georgina Harris 42-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
AntennasAntennas
• 2-PAD will use 3 sets of array antennas
• Each antenna tile will be 16 x 16 dual polarisation elements
• The central 8 x 8 elements will be ‘active’, i.e. the signals from these antennas will be amplified and processed
• The remaining antennas will be ‘loaded’ elements, i.e. they are present only to reduce the edge effects on the central 8 x 8
• Each antenna type is due to be produced as a passive tile for RF testing
• After testing, the active antennas will be used for 2-PAD.
Georgina Harris 52-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
AntennasAntennas
FlowPAD antenna
• from our colleagues at Astron
• used as a reference design by which to benchmark our other antennas
Georgina Harris 62-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
AntennasAntennas
BECA
• (Bunny Ear Combline Antenna)
• Designed by the University of Manchester
• A development of a Vivaldi Structure
Georgina Harris 72-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
AntennasAntennas
ORA
(Octagon Ring Antenna)
• Designed by the University of Manchester
• New Antenna Design – see talk by David Zhang
Georgina Harris 82-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
2-PAD LNA2-PAD LNA
• The LNA for each antenna must be impedance matched and designed to integrate mechanically with the antenna
• There are currently three teams working on LNAs in SKADS for 2-PAD– A completely new single-ended LNA developed in Indium
Phosphide in Manchester– A differential LNA designed at ASTRON at 150 impedance for
use with FlowPAD and BECA antennas– A differential LNA made up from discrete components in
Manchester at 150 for use with FlowPAD and BECA antennas
• It is likely that the discrete component LNA will be installed on 2-PAD initially, however, it will be possible for each LNA to undergo validation on the 2-PAD platform.
Georgina Harris 92-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
Gain = 72dB
Designed constructed and characterised byRichard Morrow
Gain Gain Chain Chain
Version Version 11
Georgina Harris 102-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
2-PAD 2-PAD System Design System Design
+ve Reg
Ant.polarisation
LNA Analog Conditioning
PCB
Analog Twisted
Pair
BunkerRFI Shield
PSU
Analog Conditioning
.......
Total 128 inputs
64 elements x2 polarisations
Beam
combiner
Processor
.......
Output B
eams
4 off Beamformer.Processors
Processor
ControlProcessor
Lin
eT
x/Rx Control
Timestandard
Buffers
Fro
m o
the
r b
ea
mfo
rme
r pro
c.
Beam
former
Processing
DigitalPre-
processor
AD
C
PSUDigitalPre-
processor
AD
C
.....
.....Signal Conditioning RackSignal Conditioning Rack Processing RackProcessing Rack
mini-BunkerOutdoors
64 dual channels
Up to ~20m
Signal conditioning module
• Analogue signal conditioning on replaceable mezzanine board
• Off-the-shelf A/D initially• FPGA for data conversion and
initial signal processing
Georgina Harris 112-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
ShieldedBunker
AnalogueConditioner
And SamplingRack
ProcessorRack
20Gb
ConditioningModule
Acquisition&Processing
ProcessorBlade
ProcessorBlade
ProcessorBlade
ProcessorBlade
ProcessorBlade
ProcessorBlade
ProcessorBlade
ProcessorBlade
Receivers
Front-endGain.
Acquisition&Processing
Acquisition&Processing
Acquisition&Processing
ConditioningModule
ConditioningModule
ConditioningModule
Georgina Harris 122-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
Power Module
2-channel signal conditioning module
Clock Module
2-channel acquisitionand
processing module
Signals fromfield
2 x 10GbLinks
Midp
lane
Signal conditioningSignal conditioning
Georgina Harris 132-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
Analogue Conditioning BoardAnalogue Conditioning Board
Stepattenuator
Slope/Gain
FilterLo
FilterHi
Balunand DCPower
Diff.Pair
Diff.Pair
Diff.Pair
Control
Power Reg
FrontPanel Connector
Filter TV
By-pass
Stepattenuator
Slope/Gain
FilterLo
FilterHi
Balunand DCPower
Filter TV
By-pass
Power RegDiff.Pair
Stepattenuator
Slope/Gain
FilterLo
FilterHi
Balunand DCPower
Diff.Pair
Diff.Pair
Diff.Pair
Control
Power Reg
FrontPanel Connector
Filter TV
By-pass
Stepattenuator
Slope/Gain
FilterLo
FilterHi
Balunand DCPower
Filter TV
By-pass
Power RegDiff.Pair
Georgina Harris 142-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
Analogue Conditioning BoardAnalogue Conditioning Board
Georgina Harris 152-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
DAQ BoardDAQ Board
GainDifferentialPair
10Gbps
DifferentialPair
A to DConverter
FPGA
Gain
4x PHY
4x PHY
PowerRegs.
ClockDist.
10Gbps
Connector
Front Panel
Management
GainDifferentialPair
10Gbps
DifferentialPair
A to DConverter
FPGA
Gain
4x PHY
4x PHY
PowerRegs.
ClockDist.
10Gbps
Connector
Front Panel
Management
Georgina Harris 172-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
2-PAD 2-PAD System Design System Design
+ve Reg
Ant.polarisation
LNA Analog Conditioning
PCB
Analog Twisted
Pair
BunkerRFI Shield
PSU
Analog Conditioning
.......
Total 128 inputs
64 elements x2 polarisations
Beam
combiner
Processor
.......
Output B
eams
4 off Beamformer.Processors
Processor
ControlProcessor
Lin
eT
x/Rx Control
Timestandard
Buffers
Fro
m o
the
r b
ea
mfo
rme
r pro
c.
Beam
former
Processing
DigitalPre-
processor
AD
C
PSUDigitalPre-
processor
AD
C
.....
.....Signal Conditioning RackSignal Conditioning Rack Processing RackProcessing Rack
mini-BunkerOutdoors
64 dual channels
Up to ~20m
Processing Subsystem
• 2-PAD Designed to enable the testing of different types of processing
• PrepSKA follow-on work to further investigate options
Georgina Harris 182-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
Initial Processing for 2-PADInitial Processing for 2-PAD
Cyclops processor (IBM)
• Cyclops blades in high-bandwidth rack
• 80 GFlops/blade
• Up to 48 blades/rack
• SIMD Architecture
• 160 thread units per chip
Further Options – see Chris Shenton’s presentation
Georgina Harris 192-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
Cyclops frame at JodrellCyclops frame at Jodrell
Georgina Harris 202-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
Cooling SystemCooling System
• We have a cooling system for 2-PAD which includes:
• A closed-loop controlled water cooling system used to cool the processor chips to keep them running at their most efficient
• An air conditioning system used to cool the other electronics in the bunker
• The two systems work together to keep the electronics at the correct temperature and humidity without compromising the RFI shielding of the bunker
• This cooling system will make use of ‘free’ uncooled air from outside the bunker whenever ambient temperatures permit.
Georgina Harris 212-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
2-PAD 2-PAD System Design System Design
+ve Reg
Ant.polarisation
LNA Analog Conditioning
PCB
Analog Twisted
Pair
BunkerRFI Shield
PSU
Analog Conditioning
.......
Total 128 inputs
64 elements x2 polarisations
Beam
combiner
Processor
.......
Output B
eams
4 off Beamformer.Processors
Processor
ControlProcessor
Lin
eT
x/Rx Control
Timestandard
Buffers
Fro
m o
the
r b
ea
mfo
rme
r pro
c.
Beam
former
Processing
DigitalPre-
processor
AD
C
PSUDigitalPre-
processor
AD
C
.....
.....Signal Conditioning RackSignal Conditioning Rack Processing RackProcessing Rack
mini-BunkerOutdoors
64 dual channels
Up to ~20m
Bunker and Shielding
• RFI mitigation techniques• Housing and cooling system• ‘Standard’ container structure
Georgina Harris 222-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
Processing Bunker DesignProcessing Bunker Design
The processing bunker will be manufactured to the basic pattern of a standard transport container.
Dual Function:
1. Provide RFI Shielding
2. Permits the processing bunker to be filled with computers before it is shipped
Georgina Harris 232-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
Bunker RFI shieldingBunker RFI shielding
• Connect via screened sockets• Cables through tube• Wrap foil along cable• >60dB suppression at 1GHz, so far
ARJ45 screenedconnectors
Georgina Harris 242-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
Potential SKA Station LayoutPotential SKA Station Layout
Georgina Harris 252-PAD4th SKADS Workshop, Lisbon, 2-3 October 2008
SoftwareSoftware
• A highly optimised kernel and software library has been created for the Cyclops processor from scratch in Manchester
• A comprehensive MATLAB broadband beamforming model has been developed
• We have a vendor developed software simulator for the Cyclops processor and the first version single polarisation beamformer has been implemented (in the simulator environment). This is currently being validated against the MATLAB model (refer to presentation by Aziz AhmedSaid).