Hi Marcus, In your design there is only a single RX. I think it is better to build an expandable board which can expand 2 RX 3 RX... That will only introduce a little more cost but will meet much more people's need.
On Thu, Jan 20, 2011 at 11:39 AM, James Jordan <james.jordan....@gmail.com>wrote: > Hi Marcus, > Who works on this project now? > Why choose USB as the interface to host. The USB interface became the > bandwidth bottleneck > in USRP1, so why use network interface? > > > On Thu, Jan 20, 2011 at 7:23 AM, Marcus D. Leech <mle...@ripnet.com>wrote: > >> >> http://www.sbrac.org/files/digital_receiver_cheap.pdf >> >> This has everything in one place--commit to a single host I/O, and go >> cheaper as a result. >> >> The estimated BOM cost for this, including PCB would be under $100.00. >> >> If you sacrifice very-fine tunability, then you don't need a DDC in the >> FPGA, and only need >> a CIC decimator chain, and you only need Rx logic in the FPGA, so you >> can get away with >> the smaller EP1C6 FPGA. There's a 9K-LE Xilinx Spartan-6 which is >> marginally cheaper >> ($16.44 vs $17.50) than the Altera, but only available in larger >> quantities from Digikey. >> Also, I think the Altera toolchain is cheaper (free??) -- I dunno, I'm >> not an FPGA guy. >> >> Note the use of ultra-cheap 8-bit ADCs. This design isn't going to win >> any awards for >> dynamic range, but it helps keep the BOM cost down, and as someone >> else observed, you >> get processing gain every time you reduce the bandwidth. So at 5MHz >> bandwidth, you've >> added a couple of effective bits. For the types of wide-band >> science-radio experiments >> one might want to do with this, a handful of bits is just fine. >> >> Now, I want to emphasize again that I have *no interest* in physically >> producing such a thing, >> but I'm always willing to contribute my engineering wisdom, for >> whatever that's worth. >> >> Also, to set a ground rule for future discussions. If this turns, >> yet-again, into an Ettus-bashing >> fest, I'm dropping out of the thread, and not participating in any >> further discussions. Such >> nonsense isn't productive, or even fair or reasonable. Matt and his >> employees (and part-time >> contractors, like me) are good, hard-working people with an excellent >> product, and who have >> **pioneered** reasonably-priced hardware that works well with Gnu Radio. >> >> The question I think this discussion can answer is fairly simple: are >> there design choices that can >> be made, with significant compromises in functionality, that can >> produce a design that is practically >> producible by an open-source hardware community, and will such a >> device be useful-enough over >> the types of hobbiest uses-cases we're interested in. Further, will >> such a device meet the >> delivered-price goals. >> >> If the answer to the above is "yes", then the next question is: is >> there a community of interested >> volunteers to bring the project to fruition? Such an interested >> community would involve: >> >> o High-level hardware design >> o Detailed schematic capture and PCB layout >> o FPGA firmware design >> o Host-interface (FX2?) firmware design >> o Host driver software design and implementation >> o Small-scale financial investment for initial PCBs, components, etc >> >> Once such a board works, then someone needs to be found to distribute >> either kits or finished product. >> >> Something that vaguely compares to this effort is the FunCube Dongle, >> which is a quadrature >> receiver covering 64MHz to 1.7GHz, but with 96KHz host-side bandwidth. >> That project is >> selling fully-built units for about USD 170.00. >> >> -- >> Principal Investigator >> Shirleys Bay Radio Astronomy Consortium >> http://www.sbrac.org >> >> >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> Discuss-gnuradio@gnu.org >> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> > >
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