The Path towards the SKA

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Kris Zarb Adami Jack Hickish(kza_at_astro.ox.ac.uk)
Dual Polarisation All Digital Aperture Array
2-PAD All-Digital Beamforming
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Back-End Processing
Digital Beamformer (Casper Hardware)
Multi Channel ADC (Casper Hardware)
LNA Analogue Signal Transport
Multi Channel ADC (Custom)
Digital Beamformer (Software)
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Key Message

• A beamformer needs a correlator

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2-PAD
200 MHz B/W 16-dual-pol. antennas 1024 Channels 1
Beam (in-field) (Virtex-II)
500 MHz B/W 8-dual-pol. antennas 1024 Channels 4
Beams (LAB Bench) (Virtex-V)
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Hierarchical Structure
F-splitting - Stage 1 B-combining Stage 1
.. B-combining Stage ..
ADC_0
Ant0
iBOB_0
Ant1
BEE2_0
ADC_1
Ant2
PPC
Ant3
Data Capture Visualisation
PPC
X_Pol
BEE2_1
iBOB_3
PPC
B-combining Stage N
ADC_7
PPC
Ant15
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Current system Architecture
ADC
ADC
ADC
ADC
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iBOB design
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Calibration Requirement
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Calibration
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Beamforming Block
M.a b
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BEE-2 10 gig-E alignment
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Results
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Current Measurements 4x1
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BEE2 Beams
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iBOB Digital Beams
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The balance of Power
Analogue Time Domain Beamforming (MWA) 1.25 W per channel
Analogue Phase Shift Beamforming (EMBRACE) 250mW per channel (2 Beams)
Digital Time Domain Beamforming (SMA) ? ?
Digital Phase Shift Beamforming (2-PAD) in 180nm technology 100mW per channel (JUST THE PHASE-SHIFTER)
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Summary
200 MHz B/W 16-dual-pol. antennas 1024 Channels 1
Beam (in-field) (Virtex-II)
500 MHz B/W 8-dual-pol. antennas 1024 Channels 4
Beams (LAB Bench) (Virtex-V)
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Future Work
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Digital Correlator (of sorts)
Counter
Sync
Data_Real
Data_Imaginary