> Hi John. > >> >> >> I know folks are working on a hybrid spectrometer using roach/ibob and >> GPU's. I am in need of a 1M channel, 2 pol, 400 MHz spectrometer. >> Anyone >> offer up their design as a possibility? I think GUPPI maybe could do >> it, >> but I wonder if anyone else has gotten anything going. Or could you >> build >> such beast with just a roach or 2? >> >> >> >> > A while ago I made a 1M channel, single pol, 500 MHz spectrometer on a > single ROACH. The project folder is here: > http://casper.berkeley.edu/svn/trunk/projects/roach_mspec/ > > Have a look at the block diagram, which should give an idea of the design: > http://casper.berkeley.edu/svn/trunk/projects/roach_mspec/doc/roach_mspec.pdf > > The FPGA utilization was as follows: > 90% of slices, 21% DSP, 35% BRAM > > There was also lot of room for optimisation. For example, the qdr vector > accumulator + DRAM buffer could have been replaced just a DRAM vector > accumulator. Also lots of slices could be freed up by using DSPs. The > other > bonus is you would clock your FPGA 50 Mhz slower. > > I think you could comfortably do dual-pol with 2 ROACHs.
Thanks, David. We've played with this design a bit, but I forgot its characteristics. John > > Cheers, > David > > > > > -- > David George > Karoo Array Telescope > Tel: +27 21 531-7282 > Email: [email protected] >
