[USRP-users] SBX daughtercard bandwidth problem..!!

Marcus D. Leech mleech at ripnet.com
Sun Feb 12 23:17:03 EST 2012


> Thanks Josh and Ian Buckley....:) So it means:
> 1. I cannot set the decimation or interpolation to "1" in simulink
> SDRu block? or in other words i        cannot get the sampling rate of
> 100 MSPS?? :( 
>
> 2. Is there any way using Simulink SDRu block??
>
> Regards 
>
> Salman Dinani
There's no standard mode that allows 100Msps into the host.  Doing so
would require 4-bit I and 4-bit Q,
  which reduces your dynamic range to 32dB, which isn't a lot.

But even assuming for a moment that such a mode was possible, *doing*
anything with samples arriving
  at 100Msps is going to be a significant challenge, particularly using
any kind of generic framework
  such as Gnu Radio or Simulink.  I know the GMRT people are processing
samples arriving at up to
  64Msps, and they had to custom-code a lot of things, and their
samplers operated on the PCIe bus,
  not ethernet.  They had the advantage of double-buffered
large-transfer-size DMA, and very careful
   pipelining.

Further, the maximum analog bandwidth coming out of most daughtercards
is only 40MHz, so 100Msps
   doesn't give you any advantage.

Just my small contribution.



-- 
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org






More information about the USRP-users mailing list