New Flex radio?
mo at 131.ccr.org
Wed May 16 13:44:18 CDT 2012
The Exciter board for the Quicksilver is now shipping
so for a little over a grand you get a pure digital radio that can
easily run 8 complete receive channels simultaneously.
as for connectivity, if your laptop has an expressCard slot,
that *is* a PCIe spigot, and there are extender cards
that go in the ExpressCard slot and source a cable that
will run to a stub PCIe bus crate or box that speaks PCIe.
(of course same extender card exists for physical PCIe slots, too)
Note that the Thunderbird interconnect is exactly
switched PCIe - two full-duplex channels that run
at 10Gbps in V1.0. Existing PCIe "remote bus crate"
boxes have been adapted for TBird just by doing
a different extender interface card that has TBird
Given the ubiquity of TBird going forward (all the
Intel chip sets will have it) and given that it's
a straightfoward extension of switched PCIe that
is being used now, I think PCIe is actually a
natural and good choice for a very high speed
interface to an FPGA-based DSP system. I understand the
attraction of GigE and won't complain about it, certainly
as a stop-gap, but given the trajectory of the FPGA DSP
technology, GigE won't last long and we will want
tighter coupling between the radio hardware and the
rest of the system. the choice is PCIe or ?????????
the number of interface types is going down as they
get faster since they all have to solve the same
fundamental problems. Once you do that, it's just
rearranging the bits in the packets.
given the new FPGAs with multiple fast A9s directly
attached to the FPGA, or rather the FPGA directly
to the AMBX bus in the processors, this might all
become a moot point reasonably soon if not next week.
Just run the software out there and save lots of wires.
One other note in passing.....
If you haven't kept up with what's happening with MINIX,
the putative progenitor of Linux, you really should go
and check out what's happening. Minix 3.2.x is a far, far
cry from even Minix 2.0 or 3.1.x for that matter.
NetBSD user-land tools and APIs, but most important, they are
concentrating on *reliability* as in what Andy T calls
"the Television model of computing" - you take it home,
plug it in, and it works for 10 years continuously.
they are talking about being able to upgrade the OS,
not just Userland stuff, *without* taking the system down.
pretty cool stuff.
one reason this matters is that they are targetting embedded
applications, and it might well be the ideal software platform
for the fused FPGA/MulticoreCPU parts available from all the
major FPGA folks (and Intel).
so the various wheels of incarnation keep spinning 'round and 'round,
and occassionally, they synchronize in what turn out to
be very, very interesting ways. I believe we are coming up
on such a conjunction.
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