1. The Uniboard  FPGA Processing for Astronomy
Harro Verkouter/Joint Institute for VLBI in Europe

4. Joint Institute for VLBI in Europe
MarkIV Correlator inaugurated 1998
In realtime:
16 stations
256MHz/station (1Gbit/s/station)
16 spectral points/subband resolution
0.25s shortest integration time
ASIC based
1024 correlator chips
running at 32MHz
Problems
1993 state-of-the-art hardware
EVN growing to > 16 stations
new receivers yield > 1Gbps/station

5. EVN 2015 sciencegoals Correlator 100-fold more powerfull
Multiple data streams of Gbps
at least 2GHz BW/station
Definitely more than 16 stations (32?)
10ms shortest integration time
Correlator 100-fold more powerfull
software correlators exist, best performance estimate:
128 dual quad-core nodes for realtime 16 1Gbps
does give 8x higher spectral resolution
sweet spot for performance/watt/developmentcost = FPGA
conclusion of “Next generation correlators” workshop, Groningen (NL) 2006

6. The Uniboard
Built according to Pogrebenko* meltdown criterion:
“Put as many state-of-the-art FPGAs and high speed links on one board as possible.”
Attempt to yield:
as much processing power per board as possible
as much I/O connectivity as possible
* Sergei Pogrebenko - digital engineer at JIVE

7. The Uniboard 4x 10 Gbps 4x 8 bit LVDS Backplane side Front panel side
4x10Gbps ethernet, 4GB DDR3, InterFPGA = 20Gbps

8. Features 8 Altera Stratix IV FPGA, 40nm technology
800+ k Logical Elements
x18 multipliers
goal is to run the board at 400MHz
=> 3 TMAC/s
Xilinx also has comparable 40nm FPGA
not at affordable cost
not in foreseeable future
old correlator does ~ 100TMAC/s
but is XF architecture (requires 10x as much MAC)
need 4 UniBoards to equal EVN MkIV correlator
Stratix type: EP4SGX230KF40
TMAC = Tera Multiply-Accumulate
EVN MkIV = 32MHz * 1k chips * 0.5k lags * 6MAC/lag = 100TMAC
UniBoard = 8 chips * 1k MAC * 400MHz = 3.2 TMAC

9. Powerconsumption estimates
Power each
Number
Total
FPGA
20 W 8
160 W
Interfaces (10GbE)
2 W 16
32 W
Memory (DDR3)
2.5 W
40 W
Power supply
loss 20% 1
46 W
Total power
280 W
Stratix type: EP4SGX230KF40
TMAC = Tera Multiply-Accumulate
MarkIV correlator ~10kW

10. EVN Correlator Telescope Correlator Telescope Correlator
Based on independence of subbands
Telescope
Correlator
UniBoard
Sample
filter
receiver
splitter
Telescope
Correlator
UniBoard
buffer/ FFT
X-Corr
UniBoard
buffer/ FFT
X-Corr
Stratix type: EP4SGX230KF40
TMAC = Tera Multiply-Accumulate
UniBoard
buffer/ FFT
X-Corr

11. Other projects using UniBoard
APERTIF - for focalplane-array equipped WSRT
beamformer
correlate everything with everything
Digital Receiver
using board in reverse, sample signal at the LVDS connectors
European Pulsar Timing Array
detect gravitational waves by detecting correlations between residuals on an ‘array’ of pulsars
Pulsar Binning
provide coherent de-dispersion over ~10 times broader bandwidth
RFI Mitigation
computational power + bandwidth allows to do this on-the-fly
not for dynamic RFI signals (e.g. WiFi)
Stratix type: EP4SGX230KF40
TMAC = Tera Multiply-Accumulate

12. RadioNet/FP7 Joint Research Activity
EC integrating activity that brings together all the major radio observatories in Europe
EC funding round #7 (framework programme)
awarded 2M€ over next 3 years
started January 2009
26 partners