The Uniboard is a general purpose board, developed as a part of the Radionet FP7 program, that hosts 8 Altera
StratixIV FPGAs interconnected by high speed links. It can be used standalone or as a part of a more complex
The Digital receiver application uses a single Uniboard to implement a flexible packetization of a wideband
signal in the frequency domain. It accepts a 4 GHz (8 GS/s) input bandwidth and provides up to 64 output
bands. The bandwidth and position of each output band can be independently adjusted.
The input signal is first analyzed by a polyphase filterbank, that splits the input band into 32 sub-bands with
a bandwidth of 190 MHz and a spacing of 128 MHz. The overlap among adjacent bands allows the positioning of
the output bands without dead regions. This filterbank is followed by an array of digitally defined downconverters,
each one composed of a mixer/LO and a variable decimation filter. The filter band can be adjusted in binary
steps from 1 to 128 MHz. Using tap recirculation, the filter shape remains constant over this whole range, with
about 60 dB of stopband rejection and 90% usable passband.
The output bands are packetized according to the VDIF VLBI standard, over eight 10G Ethernet links.
Further processing can be done either on board, or in a cluster of conventional PCs.
In addition, high speed ADC are in-house developed (ASIC 65nm CMOS STmicroelectronics) to feed the
Uniboard card with 8GS/s, 4GHz BW, 3bits samples.