Hi CASPERites,
Here's a somewhat fluffy RFI which I hope might start a little thought
and/or discussion over the season (acknowledging that not all in the
global collaboration celebrate the traditional Western winter holidays):
At SMA we are looking into the use of CASPER methods to build
Hi Jonathan,
Other specs ?
For SMA 8 or 10 antennas x 2 pols analog input possible
For CARMA 15 antennas x 2 pols, or 23 ants x 1 pol, or 23 ants x 2 pols
Output sample and accumulation time for cross correlation: typical
10sec, fast for longer baselines 1 sec.
Mel.
On Thu, Dec 23, 2010 at
hi jonathan,
some ideas for your correlator:
1)
300 MHz is a good target, especially for V6.
suraj has shown how to achieve 375 MHz for V5
by using floor planning and auto-placing.
suraj or i can send you his draft paper on this if you'd like.
2)
you might want to consider FFX instead of
Thanks, Suraj, it is good to of your experiences. I may ask more in
time about the details of your implementation.
Also, the practical limit, our analysis so far is purely number of
multiplies and adds, and does yet look at routing. However, is your
practical limit for Virtex 5, and
Another reason to consider FFX is more flexible selection of how
many channels you want in each subband.
ii) Equalization across a 16 GHz may be an issue. If there is too much slope
across the band, suppose in an extreme case, a change at low gains end
might make no change in the digitized
On 2. it seems to me that if we are digitizing a 9 GHz and using 20
Gsps, one still needs substantial demux (at least 64) no matter how
small the PFB.
As Sura points out this is far in excess of practical limits. This
stacks with what we have found: BW is the difficult part, large PFB
for
To the best of my knowledge, nobody's built a CASPER correlator that processes
such high bandwidths. I took a closer look at bringing 20Gsps into a ROACH2 for
MeerKAT use a few months back. My conclusion was that this would be possible
with current libraries with minimal changes. However, we
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