On 05/08/2013 04:33 PM, LD Zhang wrote:
Sorry for the confusion. I have been using USRP in a rather
micky-mouse way. For the longest time, I was just capturing data on
host computer disk and do brute force processing in MATLAB. It's time
for me to think about speed up. And the first thing is to consider the
USRP processing capability. The PLL may still be the right solution if
the PLL faithfully replicates the original signal, which I think it
should. But having the gnu-radio doing the PLL, I am not sure there is
much of a speed gain. Maybe there are intelligent ways of organizing
this so that it can be sped up? Maybe the Gnuradio is faster than
Matlab. But these days the matlab has been awful fast, not much slower
than C. Still my matlab is not organized as nicely as the gnuradio.
Right now I don't have any streamlined processing. The suggestion on
using the PFB filterbanks and PLLs in parallel and streaming operation
may have significant speed up? Your opinion is appreciated.
I can't tell you if your application will run in real-time, but the
polyphase filterbank is the most CPU-efficient way to extract multiple
(usually, more than four) signals from a sample stream in Gnuradio. You
will probably find Gnuradio much faster than offline processing in Matlab.
If the relative phase offset of multiple carriers is important, then you
really only want to run a single PLL on one of the carriers, and use the
frequency estimate to apply to all the carriers -- i.e., the entire bank
of signals -- so that phase is preserved relative to the "reference"
carrier.
--n
LD
*From:*Marcus D. Leech [mailto:mle...@ripnet.com]
*Sent:* Wednesday, May 08, 2013 4:03 PM
*To:* LD Zhang; Discuss-gnuradio@gnu.org
*Subject:* Re: [Discuss-gnuradio] How many multiple/simultaneous PLLs
can I have running on USRP2?
Or am I wrong that the resource is in the computer and not in the
USRP?
LD
It's all in the computer, unless you do an FPGA-based implementation.
Gnu Radio blocks run on the host machine, not the USRP hardware.
I admit to being a little bit surprised that you don't know that
already, given how long you've been posting things to this list,
and using USRP hardware.
--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
_______________________________________________
Discuss-gnuradio mailing list
Discuss-gnuradio@gnu.org
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
_______________________________________________
Discuss-gnuradio mailing list
Discuss-gnuradio@gnu.org
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio