The BEST-2 SKA pathfinder is composed by 32 receivers. The front ends are installed on the focal lines of 8 cylinders, offering a collecting area of about 1400 m2. The signal is sent to the receiver room via analogue optical fibre links.

Receiver chain (block diagram)Receiver chain (block diagram)

Installed on the focal lines

Installed in the receiver room

A DDC (Digital Down Converter) block and a Polyphase filter bank (“FFT” block ofthe FX correlator) has been designed and used to configure a 32 receivers FX correlator (Jason Manley, 2008).The back-end is composed of 8 IBOBs, 16 dual ADC boards (8 bit, 1GSPS) and a BEE2 FPGA cluster (1 Tops/sec).

A/D1

AD2

Ibob(Serializer)

A/D1

AD2

Ibob(Serializer)

RX1

RX2

RX n-1

RXn

Dual 1GS/sec @ 8 bit

Dual 1GS/sec @ 8 bit

InfinibandCX4 Cables

FPGA 1FPGA 1 FPGA 2FPGA 2

FPGA-3FPGA-3 FPGA-4FPGA-4

FPGA-5FPGA-5

Bee 2

5x Xilinx Virtex-2 Pro 70

Back EndBack End

The main features of BEST-2System temperature: 86 KRF Central frequency: 408 MHzFrequency BW: 16 MHzIF: 30 MHzInstantaneous BW: 16 MHzInstantaneous primary FOV: 37.62 deg2

FOV-Declination: 5.7 degFOV-Right ascension: 6.6 deg

Synthesized beam size: 0.9 deg2

Declination: 31.1 arcminRight ascension: 104 arcmin

Independent beams within FOV: 21

Continuum sensitivityBW: 16 MHzIntegration Time: 30 sec

Total power mode (full array)RMS noise / Sensitivity: 5.4 mJyRMS noise / Sensitivity: 2.0 mK

Correlation (full array)RMS noise / Sensitivity: 43.3 mJyRMS noise / Sensitivity: 2.8 mK

IF, data acquisition and processing blocks for BEST

Possible hardware/scientific tests with the BEST-2 system (in collaboration with Oxford University):

1.Multibeaming capability (tracking of a Pulsar pair in the FOV)

2.Testing post-processing hardware and algorithms (survey for dispersed transient signals of astrophysical origin)

(see SKADS newsletter #5, May 2009)